diff --git a/src/Hjets.cc b/src/Hjets.cc
index 74d1276..987e6b4 100644
--- a/src/Hjets.cc
+++ b/src/Hjets.cc
@@ -1,1113 +1,1113 @@
/**
* \authors The HEJ collaboration (see AUTHORS for details)
* \date 2019
* \copyright GPLv2 or later
*/
#include "HEJ/jets.hh"
#include "HEJ/Hjets.hh"
#include <assert.h>
#include <limits>
#include "HEJ/Constants.hh"
#ifdef HEJ_BUILD_WITH_QCDLOOP
#include "qcdloop/qcdloop.h"
#endif
const COM looprwfactor = (COM(0.,1.)*M_PI*M_PI)/pow((2.*M_PI),4);
constexpr double infinity = std::numeric_limits<double>::infinity();
namespace {
// Loop integrals
#ifdef HEJ_BUILD_WITH_QCDLOOP
COM B0DD(HLV q, double mq)
{
static std::vector<std::complex<double>> result(3);
static auto ql_B0 = [](){
ql::Bubble<std::complex<double>,double,double> ql_B0;
ql_B0.setCacheSize(100);
return ql_B0;
}();
static std::vector<double> masses(2);
static std::vector<double> momenta(1);
for(auto & m: masses) m = mq*mq;
momenta.front() = q.m2();
ql_B0.integral(result, 1, masses, momenta);
return result[0];
}
COM C0DD(HLV q1, HLV q2, double mq)
{
static std::vector<std::complex<double>> result(3);
static auto ql_C0 = [](){
ql::Triangle<std::complex<double>,double,double> ql_C0;
ql_C0.setCacheSize(100);
return ql_C0;
}();
static std::vector<double> masses(3);
static std::vector<double> momenta(3);
for(auto & m: masses) m = mq*mq;
momenta[0] = q1.m2();
momenta[1] = q2.m2();
momenta[2] = (q1+q2).m2();
ql_C0.integral(result, 1, masses, momenta);
return result[0];
}
COM D0DD(HLV q1,HLV q2, HLV q3, double mq)
{
static std::vector<std::complex<double>> result(3);
static auto ql_D0 = [](){
ql::Box<std::complex<double>,double,double> ql_D0;
ql_D0.setCacheSize(100);
return ql_D0;
}();
static std::vector<double> masses(4);
static std::vector<double> momenta(6);
for(auto & m: masses) m = mq*mq;
momenta[0] = q1.m2();
momenta[1] = q2.m2();
momenta[2] = q3.m2();
momenta[3] = (q1+q2+q3).m2();
momenta[4] = (q1+q2).m2();
momenta[5] = (q2+q3).m2();
ql_D0.integral(result, 1, masses, momenta);
return result[0];
}
COM A1(HLV q1, HLV q2, double mt)
// As given in Eq. (B.2) of VDD
{
double q12,q22,Q2;
HLV Q;
double Delta3,mt2;
COM ans(COM(0.,0.));
q12=q1.m2();
q22=q2.m2();
Q=-q1-q2; // Define all momenta ingoing as in appendix of VDD
Q2=Q.m2();
Delta3=q12*q12+q22*q22+Q2*Q2-2*q12*q22-2*q12*Q2-2*q22*Q2;
assert(mt > 0.);
mt2=mt*mt;
ans=looprwfactor*COM(0,-1)*C0DD(q1,q2,mt)*( 4.*mt2/Delta3*(Q2-q12-q22)
-1.-4.*q12*q22/Delta3-12.*q12*q22*Q2/Delta3/Delta3*(q12+q22-Q2) )
- looprwfactor*COM(0,-1)*( B0DD(q2,mt)-B0DD(Q,mt) )
* ( 2.*q22/Delta3+12.*q12*q22/Delta3/Delta3*(q22-q12+Q2) )
- looprwfactor*COM(0,-1)*( B0DD(q1,mt)-B0DD(Q,mt) )
* ( 2.*q12/Delta3+12.*q12*q22/Delta3/Delta3*(q12-q22+Q2) )
- 2./Delta3/16/M_PI/M_PI*(q12+q22-Q2);
return ans;
}
COM A2(HLV q1, HLV q2, double mt)
// As given in Eq. (B.2) of VDD, but with high energy limit
// of invariants taken.
{
double q12,q22,Q2;
HLV Q;
double Delta3,mt2;
COM ans(COM(0.,0.));
assert(mt > 0.);
mt2=mt*mt;
q12=q1.m2();
q22=q2.m2();
Q=-q1-q2; // Define all momenta ingoing as in appendix of VDD
Q2=Q.m2();
Delta3=q12*q12+q22*q22+Q2*Q2-2*q12*q22-2*q12*Q2-2*q22*Q2;
ans=looprwfactor*COM(0,-1)*C0DD(q1,q2,mt)*( 2.*mt2+1./2.*(q12+q22-Q2)
+2.*q12*q22*Q2/Delta3 )
+looprwfactor*COM(0,-1)*(B0DD(q2,mt)-B0DD(Q,mt))
*q22*(q22-q12-Q2)/Delta3
+looprwfactor*COM(0,-1)*(B0DD(q1,mt)-B0DD(Q,mt))
*q12*(q12-q22-Q2)/Delta3+1./16/M_PI/M_PI;
return ans;
}
#else // no QCDloop
COM A1(HLV, HLV, double) {
throw std::logic_error{"A1 called without QCDloop support"};
}
COM A2(HLV, HLV, double) {
throw std::logic_error{"A2 called without QCDloop support"};
}
#endif
void to_current(const HLV & q, current & ret){
ret[0]=q.e();
ret[1]=q.x();
ret[2]=q.y();
ret[3]=q.z();
}
/**
* @brief Higgs vertex contracted with current @param C1 and @param C2
*/
COM cHdot(const current & C1, const current & C2, const current & q1,
const current & q2, double mt, bool incBot, double mb)
{
if (mt == infinity) {
return (cdot(C1,C2)*cdot(q1,q2)-cdot(C1,q2)*cdot(C2,q1))/(3*M_PI*HEJ::vev);
}
else {
HLV vq1,vq2;
vq1.set(q1[1].real(),q1[2].real(),q1[3].real(),q1[0].real());
vq2.set(q2[1].real(),q2[2].real(),q2[3].real(),q2[0].real());
// first minus sign obtained because of q1-difference to VDD
// Factor is because 4 mt^2 g^2/HEJ::vev A1 -> 16 pi mt^2/HEJ::vev alphas,
if(!(incBot))
return 16.*M_PI*mt*mt/HEJ::vev*(-cdot(C1,q2)*cdot(C2,q1)*A1(-vq1,vq2,mt)
-cdot(C1,C2)*A2(-vq1,vq2,mt));
else
return 16.*M_PI*mt*mt/HEJ::vev*(-cdot(C1,q2)*cdot(C2,q1)*A1(-vq1,vq2,mt)
-cdot(C1,C2)*A2(-vq1,vq2,mt))
+ 16.*M_PI*mb*mb/HEJ::vev*(-cdot(C1,q2)*cdot(C2,q1)*A1(-vq1,vq2,mb)
-cdot(C1,C2)*A2(-vq1,vq2,mb));
}
}
//@{
/**
* @brief Higgs+Jets FKL Contributions, function to handle all incoming types.
* @param p1out Outgoing Particle 1. (W emission)
* @param p1in Incoming Particle 1. (W emission)
* @param p2out Outgoing Particle 2 (Quark, unordered emission this side.)
* @param p2in Incoming Particle 2 (Quark, unordered emission this side.)
* @param q1 t-channel momenta into higgs vertex
* @param q2 t-channel momenta out of higgs vertex
* @param mt top mass (inf or value)
* @param incBot Bool, to include bottom mass (true) or not (false)?
* @param mb bottom mass (value)
* @param pg Unordered Gluon momenta
* @param aqlineb Bool. Is Backwards quark line an anti-quark line?
* @param aqlinef Bool. Is Forwards quark line an anti-quark line?
*
* Calculates j^\mu H j_\mu. FKL with higgs vertex somewhere in the FKL chain.
* Handles all possible incoming states.
*/
double j_h_j(HLV p1out, HLV p1in, HLV p2out, HLV p2in,
HLV q1, HLV q2, double mt, bool incBot,
double mb, bool aqlineb, bool aqlinef){
current j1p,j1m,j2p,j2m, q1v, q2v;
// Note need to flip helicities in anti-quark case.
joi(p1out,!aqlineb, p1in,!aqlineb, j1p);
joi(p1out, aqlineb, p1in, aqlineb, j1m);
joi(p2out,!aqlinef, p2in,!aqlinef, j2p);
joi(p2out, aqlinef, p2in, aqlinef, j2m);
to_current(q1, q1v);
to_current(q2, q2v);
COM Mmp=cHdot(j1m,j2p,q1v,q2v,mt, incBot, mb);
COM Mmm=cHdot(j1m,j2m,q1v,q2v,mt, incBot, mb);
COM Mpp=cHdot(j1p,j2p,q1v,q2v,mt, incBot, mb);
COM Mpm=cHdot(j1p,j2m,q1v,q2v,mt, incBot, mb);
// average over helicities
const double sst=(abs2(Mmp)+abs2(Mmm)+abs2(Mpp)+abs2(Mpm))/4.;
return sst/((p1in-p1out).m2()*(p2in-p2out).m2()*q1.m2()*q2.m2());
}
} // namespace anonymous
double ME_H_qQ(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, false, false);
}
double ME_H_qQbar(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, false, true);
}
double ME_H_qbarQ(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, true, false);
}
double ME_H_qbarQbar(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, true, true);
}
double ME_H_qg(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, false, false)
* K_g(p2out,p2in)/HEJ::C_A;
}
double ME_H_qbarg(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, true, false)
* K_g(p2out,p2in)/HEJ::C_A;
}
double ME_H_gg(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV q1, HLV q2,
double mt, bool incBot, double mb){
return j_h_j(p1out, p1in, p2out, p2in, q1, q2, mt, incBot, mb, false, false)
* K_g(p2out,p2in)/HEJ::C_A * K_g(p1out,p1in)/HEJ::C_A;
}
//@}
namespace {
//@{
/// @brief Higgs vertex contracted with one current
CCurrent jH(HLV pout, bool helout, HLV pin,
bool helin, HLV q1, HLV q2,
double mt, bool incBot, double mb)
{
CCurrent j2 = joi(pout,helout,pin,helin);
CCurrent jq2(q2.e(),q2.px(),q2.py(),q2.pz());
if(mt == infinity)
return ((q1.dot(q2))*j2 - j2.dot(q1)*jq2)/(3*M_PI*HEJ::vev);
else
{
if(incBot)
return (-16.*M_PI*mb*mb/HEJ::vev*j2.dot(q1)*jq2*A1(-q1,q2,mb)
-16.*M_PI*mb*mb/HEJ::vev*j2*A2(-q1,q2,mb))
+ (-16.*M_PI*mt*mt/HEJ::vev*j2.dot(q1)*jq2*A1(-q1,q2,mt)
-16.*M_PI*mt*mt/HEJ::vev*j2*A2(-q1,q2,mt));
else
return (-16.*M_PI*mt*mt/HEJ::vev*j2.dot(q1)*jq2*A1(-q1,q2,mt)
-16.*M_PI*mt*mt/HEJ::vev*j2*A2(-q1,q2,mt));
}
}
//@}
//@{
/**
* @brief Higgs+Jets Unordered Contributions, function to handle all incoming types.
* @param pg Unordered Gluon momenta
* @param p1out Outgoing Particle 1. (W emission)
* @param p1in Incoming Particle 1. (W emission)
* @param p2out Outgoing Particle 2 (Quark, unordered emission this side.)
* @param p2in Incoming Particle 2 (Quark, unordered emission this side.)
* @param q1 t-channel momenta into higgs vertex
* @param q2 t-channel momenta out of higgs vertex
* @param mt top mass (inf or value)
* @param incBot Bool, to include bottom mass (true) or not (false)?
* @param mb bottom mass (value)
* @param aqlineb Bool. Is Backwards quark line an anti-quark line?
* @param aqlinef Bool. Is Forwards quark line an anti-quark line?
*
* Calculates j_{uno}^\mu H j_\mu. Unordered with higgs vertex
* somewhere in the FKL chain. Handles all possible incoming states.
*/
double juno_h_j(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV qH1, HLV qH2,
double mt, bool incBot, double mb, bool aqlineb
){
// This construction is taking rapidity order: pg > p1out >> p2out
HLV q1=p1in-p1out; // Top End
HLV q2=-(p2in-p2out); // Bottom End
HLV qg=p1in-p1out-pg; // Extra bit post-gluon
// Note <p1|eps|pa> current split into two by gauge choice.
// See James C's Thesis (p72). <p1|eps|pa> -> <p1|pg><pg|pa>
CCurrent mj1p=joi(p1out,!aqlineb, p1in,!aqlineb);
CCurrent mj1m=joi(p1out, aqlineb, p1in, aqlineb);
CCurrent jgap=joi(pg, !aqlineb, p1in,!aqlineb);
CCurrent jgam=joi(pg, aqlineb, p1in, aqlineb);
// Note for function joo(): <p1+|pg+> = <pg-|p1->.
CCurrent j2gp=joo(p1out, !aqlineb, pg, !aqlineb);
CCurrent j2gm=joo(p1out, aqlineb, pg, aqlineb);
CCurrent mjH2p=jH(p2out, true,p2in, true,qH1,qH2,mt,incBot,mb);
CCurrent mjH2m=jH(p2out,false,p2in,false,qH1,qH2,mt,incBot,mb);
// Dot products of these which occur again and again
COM MHmp=mj1m.dot(mjH2p);
COM MHmm=mj1m.dot(mjH2m);
COM MHpp=mj1p.dot(mjH2p);
COM MHpm=mj1p.dot(mjH2m);
CCurrent p2o(p2out), p2i(p2in), p1o(p1out), p1i(p1in), qsum(q1+qg);
CCurrent Lmm=(qsum*(MHmm) + (-2.*mjH2m.dot(pg))*mj1m + 2.*mj1m.dot(pg)*mjH2m
+ ( p2o/pg.dot(p2out) + p2i/pg.dot(p2in) )*( qg.m2()*MHmm/2.) )/q1.m2();
CCurrent Lmp=(qsum*(MHmp) + (-2.*mjH2p.dot(pg))*mj1m + 2.*mj1m.dot(pg)*mjH2p
+ ( p2o/pg.dot(p2out) + p2i/pg.dot(p2in) )*( qg.m2()*MHmp/2.) )/q1.m2();
CCurrent Lpm=(qsum*(MHpm) + (-2.*mjH2m.dot(pg))*mj1p + 2.*mj1p.dot(pg)*mjH2m
+ ( p2o/pg.dot(p2out) + p2i/pg.dot(p2in) )*( qg.m2()*MHpm/2.) )/q1.m2();
CCurrent Lpp=(qsum*(MHpp) + (-2.*mjH2p.dot(pg))*mj1p + 2.*mj1p.dot(pg)*mjH2p
+ ( p2o/pg.dot(p2out) + p2i/pg.dot(p2in) )*( qg.m2()*MHpp/2.) )/q1.m2();
CCurrent U1mm=(jgam.dot(mjH2m)*j2gm+2.*p1o*MHmm)/(p1out+pg).m2();
CCurrent U1mp=(jgam.dot(mjH2p)*j2gm+2.*p1o*MHmp)/(p1out+pg).m2();
CCurrent U1pm=(jgap.dot(mjH2m)*j2gp+2.*p1o*MHpm)/(p1out+pg).m2();
CCurrent U1pp=(jgap.dot(mjH2p)*j2gp+2.*p1o*MHpp)/(p1out+pg).m2();
CCurrent U2mm=((-1.)*j2gm.dot(mjH2m)*jgam+2.*p1i*MHmm)/(p1in-pg).m2();
CCurrent U2mp=((-1.)*j2gm.dot(mjH2p)*jgam+2.*p1i*MHmp)/(p1in-pg).m2();
CCurrent U2pm=((-1.)*j2gp.dot(mjH2m)*jgap+2.*p1i*MHpm)/(p1in-pg).m2();
CCurrent U2pp=((-1.)*j2gp.dot(mjH2p)*jgap+2.*p1i*MHpp)/(p1in-pg).m2();
constexpr double cf=HEJ::C_F;
double amm=cf*(2.*vre(Lmm-U1mm,Lmm+U2mm))+2.*cf*cf/3.*vabs2(U1mm+U2mm);
double amp=cf*(2.*vre(Lmp-U1mp,Lmp+U2mp))+2.*cf*cf/3.*vabs2(U1mp+U2mp);
double apm=cf*(2.*vre(Lpm-U1pm,Lpm+U2pm))+2.*cf*cf/3.*vabs2(U1pm+U2pm);
double app=cf*(2.*vre(Lpp-U1pp,Lpp+U2pp))+2.*cf*cf/3.*vabs2(U1pp+U2pp);
double ampsq=-(amm+amp+apm+app)/(q2.m2()*qH2.m2());
// Now add the t-channels for the Higgs
ampsq/=qH1.m2()*qg.m2();
ampsq/=16.;
// Factor of (Cf/Ca) for each quark to match ME_H_qQ.
ampsq*=HEJ::C_F*HEJ::C_F/HEJ::C_A/HEJ::C_A;
return ampsq;
}
} // namespace anonymous
-double ME_H_unof_qQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV qH1,
- HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false);
+double ME_H_unof_qQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false);
}
double ME_H_unof_qbarQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true);
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false);
}
double ME_H_unof_qQbar(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false);
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true);
}
double ME_H_unof_qbarQbar(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true);
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true);
}
double ME_H_unof_qg(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false)*K_g(p2out,p2in)/HEJ::C_F;
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false)*K_g(p1out,p1in)/HEJ::C_F;
}
double ME_H_unof_qbarg(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true)*K_g(p2out,p2in)/HEJ::C_F;
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true)*K_g(p1out,p1in)/HEJ::C_F;
}
-double ME_H_unob_qQ(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false);
+double ME_H_unob_qQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV qH1,
+ HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false);
}
-double ME_H_unob_qbarQ(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false);
+double ME_H_unob_qbarQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true);
}
-double ME_H_unob_qQbar(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true);
+double ME_H_unob_qQbar(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false);
}
-double ME_H_unob_qbarQbar(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true);
+double ME_H_unob_qbarQbar(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true);
}
-double ME_H_unob_gQ(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, false)*K_g(p1out,p1in)/HEJ::C_F;
+double ME_H_unob_gQ(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, false)*K_g(p2out,p2in)/HEJ::C_F;
}
-double ME_H_unob_gQbar(HLV p1out, HLV p1in, HLV pg, HLV p2out, HLV p2in,
- HLV qH1, HLV qH2, double mt, bool incBot, double mb){
- return juno_h_j(pg, p2out, p2in, p1out, p1in, qH2, qH1, mt, incBot, mb, true)*K_g(p1out,p1in)/HEJ::C_F;
+double ME_H_unob_gQbar(HLV pg, HLV p1out, HLV p1in, HLV p2out, HLV p2in,
+ HLV qH1, HLV qH2, double mt, bool incBot, double mb){
+ return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, incBot, mb, true)*K_g(p2out,p2in)/HEJ::C_F;
}
//@}
// Begin finite mass stuff
#ifdef HEJ_BUILD_WITH_QCDLOOP
namespace {
// All the stuff needed for the box functions in qg->qgH now...
COM E1(HLV k1, HLV k2, HLV kh, double mq){
HLV q2=-(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor*(-s12*D0DD(k2, k1, q2, mq)*(1 - 8.*mq*mq/s12 + S2/(2.*s12) +
S2*(s12 - 8.*mq*mq)*(s34 + S1)/(2.*s12*Delta) +
2.*(s34 + S1)*(s34 + S1)/Delta +
S2*pow((s34 + S1),3)/Delta/Delta) - ((s12 + S2)*C0DD(k2,
k1 + q2, mq) -
s12*C0DD(k1, k2, mq) + (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S1*C0DD(k1, q2,
mq))*(S2*(s12 - 4.*mq*mq)/(2.*s12*Delta) +
2.*(s34 + S1)/Delta +
S2*pow((s34 + S1),2)/Delta/Delta) + (C0DD(k1, q2, mq) -
C0DD(k1 + k2, q2, mq))*(1. - 4.*mq*mq/s12) -
C0DD(k1 + k2, q2, mq)*2.*s34/
S1 - (B0DD(k1 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*2.*s34*(s34 +
S1)/(S1*Delta) + (B0DD(q2, mq) -
B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2,
mq))*(2.*s34*(s34 +
S1)*(S1 - S2)/(Delta*Sigma) +
2.*s34*(s34 + S1)/(S1*Delta)) + (B0DD(k1 + k2, mq) -
B0DD(k1 + k2 + q2,
mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2, mq))*2.*(s34 +
S1)*(2.*s12*s34 -
S2*(S1 + S2))/(Delta*Sigma));
}
COM F1(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor*(-S2*D0DD(k1, k2, q2,
mq)*(0.5 - (s12 - 8.*mq*mq)*(s34 + S2)/(2.*Delta) -
s12*pow((s34 + S2),3)/Delta/Delta) + ((s12 + S1)*C0DD(k1,
k2 + q2, mq) -
s12*C0DD(k1, k2, mq) - (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S2*C0DD(k2, q2,
mq))*(S2*(s12 - 4.*mq*mq)/(2.*s12*Delta) +
S2*pow((s34 + S2),2)/Delta/Delta)
- (C0DD(k1 + k2, q2, mq) - C0DD(k1, k2 + q2, mq))*(1. - 4.*mq*mq/s12)
- C0DD(k1, k2 + q2, mq) + (B0DD(k2 + q2, mq) -
B0DD(k1 + k2 + q2,
mq))*2.*pow((s34 + S2),2)/((s12 + S1)*Delta) - (B0DD(
q2, mq) - B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2, mq))*2.*s34*(s34 +
S2)*(S2 - S1)/(Delta*Sigma) + (B0DD(
k1 + k2, mq) -
B0DD(k1 + k2 + q2,
mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2, mq))*2.*(s34 +
S2)*(2.*s12*s34 -
S2*(S1 + S2))/(Delta*Sigma));
}
COM G1(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
return looprwfactor*(S2*D0DD(k1, q2, k2,
mq)*(Delta/s12/s12 - 4.*mq*mq/s12) -
S2*((s12 + S1)*C0DD(k1, k2 + q2, mq) -
S1*C0DD(k1, q2, mq))*(1./
s12/s12 - (s12 - 4.*mq*mq)/(2.*s12*Delta)) -
S2*((s12 + S2)*C0DD(k1 + q2, k2, mq) -
S2*C0DD(k2, q2, mq))*(1./
s12/s12 + (s12 - 4.*mq*mq)/(2.*s12*Delta)) -
C0DD(k1, q2, mq) - (C0DD(k1, k2 + q2, mq) -
C0DD(k1, q2, mq))*4.*mq*mq/
s12 + (B0DD(k1 + q2, mq) - B0DD(k1 + k2 + q2, mq))*2./
s12 + (B0DD(k1 + q2, mq) -
B0DD(q2, mq))*2.*s34/(s12*S1) + (B0DD(k2 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*2.*(s34 + S2)/(s12*(s12 + S1)));
}
COM E4(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor* (-s12*D0DD(k2, k1, q2,
mq)*(0.5 - (S1 - 8.*mq*mq)*(s34 + S1)/(2.*Delta) -
s12*pow((s34 + S1),3)/Delta/Delta) + ((s12 + S2)*C0DD(k2,
k1 + q2, mq) -
s12*C0DD(k1, k2, mq) + (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S1*C0DD(k1, q2, mq))*((S1 - 4.*mq*mq)/(2.*Delta) +
s12*pow((s34 + S1),2)/Delta/Delta) -
C0DD(k1 + k2, q2, mq) + (B0DD(k1 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*(2.*s34/Delta +
2.*s12*(s34 + S1)/((s12 + S2)*Delta)) - (B0DD(
q2, mq) - B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2,
mq))*((2.*s34*(2.*s12*s34 - S2*(S1 + S2) +
s12*(S1 - S2)))/(Delta*Sigma)) + (B0DD(k1 + k2, mq) -
B0DD(k1 + k2 + q2, mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2, mq))
*((2.*s12*(2.*s12*s34 - S1*(S1 + S2) + s34*(S2 - S1)))/(Delta*Sigma)));
}
COM F4(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor* (-s12*D0DD(k1, k2, q2,
mq)*(0.5 + (S1 - 8.*mq*mq)*(s34 + S2)/(2.*Delta) +
s12*pow((s34 + S2),3)/Delta/Delta) - ((s12 + S1)*C0DD(k1,
k2 + q2, mq) -
s12*C0DD(k1, k2, mq) - (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S2*C0DD(k2, q2, mq))*((S1 - 4.*mq*mq)/(2.*Delta) +
s12*pow((s34 + S2),2)/Delta/Delta) -
C0DD(k1 + k2, q2, mq) - (B0DD(k2 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*2.*(s34 +
S2)/Delta + (B0DD(q2, mq) -
B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2, mq))*2.*s34*(2.*s12*s34 -
S1*(S1 + S2) +
s12*(S2 - S1))/(Delta*Sigma) - (B0DD(k1 + k2, mq) -
B0DD(k1 + k2 + q2, mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2, mq))
*(2.*s12*(2.*s12*s34 - S2*(S1 + S2) + s34*(S1 - S2))/(Delta*Sigma)));
}
COM G4(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
return looprwfactor* (-D0DD(k1, q2, k2,
mq)*(Delta/s12 + (s12 + S1)/2. -
4.*mq*mq) + ((s12 + S1)*C0DD(k1, k2 + q2, mq) -
S1*C0DD(k1, q2, mq))*(1./
s12 - (S1 - 4.*mq*mq)/(2.*Delta)) + ((s12 + S2)*C0DD(
k1 + q2, k2, mq) -
S2*C0DD(k2, q2, mq))*(1./
s12 + (S1 - 4.*mq*mq)/(2.*Delta)) + (B0DD(
k1 + k2 + q2, mq) -
B0DD(k1 + q2, mq))*2./(s12 + S2));
}
COM E10(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor*(-s12*D0DD(k2, k1, q2, mq)*((s34 + S1)/Delta +
12.*mq*mq*S1*(s34 + S1)/Delta/Delta -
4.*s12*S1*pow((s34 + S1),3)/Delta/Delta/Delta) - ((s12 + S2)*C0DD(k2, k1 + q2, mq) -
s12*C0DD(k1, k2, mq) + (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S1*C0DD(k1, q2, mq))*(1./Delta +
4.*mq*mq*S1/Delta/Delta -
4.*s12*S1*pow((s34 + S1),2)/Delta/Delta/Delta) +
C0DD(k1 + k2, q2, mq)*(4.*s12*s34*(S1 - S2)/(Delta*Sigma) -
4.*(s12 -
2.*mq*mq)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma)) + (B0DD(k1 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*(4.*(s34 + S1)/((s12 + S2)*Delta) +
8.*S1*(s34 + S1)/Delta/Delta) + (B0DD(q2, mq) -
B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2, mq))*(12.*s34*(2.*s12 + S1 +
S2)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma*Sigma) -
4.*s34*(4.*s12 + 3.*S1 +
S2)/(Delta*Sigma) +
8.*s12*s34*(s34*(s12 + S2) -
S1*(s34 +
S1))/(Delta*Delta*Sigma)) + (B0DD(k1 + k2, mq) -
B0DD(k1 + k2 + q2, mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2,
mq))*(12.*s12*(2.*s34 + S1 +
S2)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma*Sigma) +
8.*s12*S1*(s34*(s12 + S2) -
S1*(s34 +
S1))/(Delta*Delta*Sigma))) + (COM(0.,1.)/(4.*M_PI*M_PI))*((2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma));
}
COM F10(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, Sigma, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
Sigma = 4.*s12*s34 - pow(S1+S2,2);
return looprwfactor* (s12*D0DD(k1, k2, q2,
mq)*((s34 + S2)/Delta - 4.*mq*mq/Delta +
12.*mq*mq*s34*(s12 + S1)/Delta/Delta -
4.*s12*pow((s34 + S2),2)/Delta/Delta -
4.*s12*S1*pow((s34 + S2),3)/Delta/Delta/Delta) + ((s12 + S1)*C0DD(k1, k2 + q2, mq) -
s12*C0DD(k1, k2, mq) - (S1 - S2)*C0DD(k1 + k2, q2, mq) -
S2*C0DD(k2, q2, mq))*(1./Delta +
4.*mq*mq*S1/Delta/Delta -
4.*s12*(s34 + S2)/Delta/Delta -
4.*s12*S1*pow((s34 + S2),2)/Delta/Delta/Delta) -
C0DD(k1 + k2, q2, mq)*(4.*s12*s34/(S2*Delta) +
4.*s12*s34*(S2 - S1)/(Delta*Sigma) +
4.*(s12 -
2.*mq*mq)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma)) - (B0DD(
k2 + q2, mq) -
B0DD(k1 + k2 + q2, mq))*(4.*s34/(S2*Delta) +
8.*s34*(s12 + S1)/Delta/Delta) - (B0DD(q2, mq) -
B0DD(k1 + k2 + q2, mq) +
s12*C0DD(k1 + k2, q2,
mq))*(-12*s34*(2*s12 + S1 +
S2)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma*Sigma) -
4.*s12*s34*s34/(S2*Delta*Delta) +
4.*s34*S1/(Delta*Sigma) -
4.*s34*(s12*s34*(2.*s12 + S2) -
S1*S1*(2.*s12 +
S1))/(Delta*Delta*Sigma)) - (B0DD(k1 + k2, mq) -
B0DD(k1 + k2 + q2, mq) - (s34 + S1 + S2)*C0DD(k1 + k2, q2, mq))*(-12.*s12*(2.*s34 + S1 +
S2)*(2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma*Sigma) +
8.*s12*(2.*s34 + S1)/(Delta*Sigma) -
8.*s12*s34*(2.*s12*s34 - S1*(S1 + S2) +
s12*(S2 -
S1))/(Delta*Delta*Sigma))) + (COM(0.,1.)/(4.*M_PI*M_PI))*((2.*s12*s34 -
S1*(S1 + S2))/(Delta*Sigma));
}
COM G10(HLV k1, HLV k2, HLV kh, double mq){
HLV q2 = -(k1+k2+kh);
double Delta, S1, S2, s12, s34;
S1 = 2.*k1.dot(q2);
S2 = 2.*k2.dot(q2);
s12 = 2.*k1.dot(k2);
s34 = q2.m2();
Delta = s12*s34 - S1*S2;
return looprwfactor* (-D0DD(k1, q2, k2, mq)*(1. +
4.*S1*mq*mq/Delta) + ((s12 + S1)*C0DD(k1,
k2 + q2, mq) -
S1*C0DD(k1, q2, mq))*(1./Delta +
4.*S1*mq*mq/Delta/Delta) - ((s12 + S2)*C0DD(k1 + q2,
k2, mq) - S2*C0DD(k2, q2, mq))*(1./Delta +
4.*S1*mq*mq/Delta/Delta) + (B0DD(k1 + k2 + q2, mq) -
B0DD(k1 + q2, mq))*4.*(s34 +
S1)/(Delta*(s12 + S2)) + (B0DD(q2, mq) -
B0DD(k2 + q2, mq))*4.*s34/(Delta*S2));
}
COM H1(HLV k1, HLV k2, HLV kh, double mq){
return E1(k1,k2,kh,mq)+F1(k1,k2,kh,mq)+G1(k1,k2,kh,mq);
}
COM H4(HLV k1, HLV k2, HLV kh, double mq){
return E4(k1,k2,kh,mq)+F4(k1,k2,kh,mq)+G4(k1,k2,kh,mq);
}
COM H10(HLV k1, HLV k2, HLV kh, double mq){
return E10(k1,k2,kh,mq)+F10(k1,k2,kh,mq)+G10(k1,k2,kh,mq);
}
COM H2(HLV k1, HLV k2, HLV kh, double mq){
return -1.*H1(k2,k1,kh,mq);
}
COM H5(HLV k1, HLV k2, HLV kh, double mq){
return -1.*H4(k2,k1,kh,mq);
}
COM H12(HLV k1, HLV k2, HLV kh, double mq){
return -1.*H10(k2,k1,kh,mq);
}
// FL and FT functions
COM FL(HLV q1, HLV q2, double mq){
HLV Q = q1 + q2;
double detQ2 = q1.m2()*q2.m2() - q1.dot(q2)*q1.dot(q2);
return -1./(2.*detQ2)*((2.-
3.*q1.m2()*q2.dot(Q)/detQ2)*(B0DD(q1, mq) -
B0DD(Q, mq)) + (2. -
3.*q2.m2()*q1.dot(Q)/detQ2)*(B0DD(q2, mq) -
B0DD(Q, mq)) - (4.*mq*mq + q1.m2() + q2.m2() +
Q.m2() - 3.*q1.m2()*q2.m2()*Q.m2()/detQ2)*C0DD(
q1, q2, mq) - 2.);
}
COM FT(HLV q1, HLV q2, double mq){
HLV Q = q1 + q2;
double detQ2 = q1.m2()*q2.m2() - q1.dot(q2)*q1.dot(q2);
return -1./(2.*detQ2)*(Q.m2()*(B0DD(q1, mq) + B0DD(q2, mq) - 2.*B0DD(Q, mq) -
2.*q1.dot(q2)*C0DD(q1, q2, mq)) + (q1.m2() -
q2.m2()) *(B0DD(q1, mq) - B0DD(q2, mq))) -
q1.dot(q2)*FL(q1, q2, mq);
}
HLV ParityFlip(HLV p){
HLV flippedVector;
flippedVector.setE(p.e());
flippedVector.setX(-p.x());
flippedVector.setY(-p.y());
flippedVector.setZ(-p.z());
return flippedVector;
}
/// @brief HC amp for qg->qgH with finite top (i.e. j^{++}_H)
void g_gH_HC(HLV pa, HLV p1,
HLV pH, double mq, current &retAns)
{
current cura1,pacur,p1cur,pHcur,conjeps1,conjepsH1,epsa,epsHa,epsHapart1,
epsHapart2,conjepsH1part1,conjepsH1part2;
COM ang1a,sqa1;
const double F = 4.*mq*mq/HEJ::vev;
// Easier to have the whole thing as current object so I can use cdot functionality.
// Means I need to write pa,p1 as current objects
to_current(pa, pacur);
to_current(p1,p1cur);
to_current(pH,pHcur);
bool gluonforward = true;
if(pa.z() < 0)
gluonforward = false;
//HEJ gauge
jio(pa,false,p1,false,cura1);
if(gluonforward){
// sqrt(2pa_-/p1_-)*p1_perp/abs(p1_perp)
ang1a = sqrt(pa.plus()*p1.minus())*(p1.x()+COM(0.,1.)*p1.y())/p1.perp();
// sqrt(2pa_-/p1_-)*p1_perp*/abs(p1_perp)
sqa1 = sqrt(pa.plus()*p1.minus())*(p1.x()-COM(0.,1.)*p1.y())/p1.perp();
} else {
ang1a = sqrt(pa.minus()*p1.plus());
sqa1 = sqrt(pa.minus()*p1.plus());
}
const double prop = (pa-p1-pH).m2();
cmult(-1./sqrt(2)/ang1a,cura1,conjeps1);
cmult(1./sqrt(2)/sqa1,cura1,epsa);
const COM Fta = FT(-pa,pa-pH,mq)/(pa-pH).m2();
const COM Ft1 = FT(-p1-pH,p1,mq)/(p1+pH).m2();
const COM h4 = H4(p1,-pa,pH,mq);
const COM h5 = H5(p1,-pa,pH,mq);
const COM h10 = H10(p1,-pa,pH,mq);
const COM h12 = H12(p1,-pa,pH,mq);
cmult(Fta*pa.dot(pH), epsa, epsHapart1);
cmult(-1.*Fta*cdot(pHcur,epsa), pacur, epsHapart2);
cmult(Ft1*cdot(pHcur,conjeps1), p1cur, conjepsH1part1);
cmult(-Ft1*p1.dot(pH), conjeps1, conjepsH1part2);
cadd(epsHapart1, epsHapart2, epsHa);
cadd(conjepsH1part1, conjepsH1part2, conjepsH1);
const COM aH1 = cdot(pHcur, cura1);
current T1,T2,T3,T4,T5,T6,T7,T8,T9,T10;
if(gluonforward){
cmult(sqrt(2.)*sqrt(p1.plus()/pa.plus())*prop/sqa1, conjepsH1, T1);
cmult(-sqrt(2.)*sqrt(pa.plus()/p1.plus())*prop/ang1a, epsHa, T2);
}
else{
cmult(-sqrt(2.)*sqrt(p1.minus()/pa.minus())
*((p1.x()-COM(0.,1.)*p1.y())/p1.perp())*prop/sqa1, conjepsH1, T1);
cmult(sqrt(2.)*sqrt(pa.minus()/p1.minus())
*((p1.x()-COM(0.,1.)*p1.y())/p1.perp())*prop/ang1a, epsHa, T2);
}
cmult(sqrt(2.)/ang1a*aH1, epsHa, T3);
cmult(sqrt(2.)/sqa1*aH1, conjepsH1, T4);
cmult(-sqrt(2.)*Fta*pa.dot(p1)*aH1/sqa1, conjeps1, T5);
cmult(-sqrt(2.)*Ft1*pa.dot(p1)*aH1/ang1a, epsa, T6);
cmult(-aH1/sqrt(2.)/sqa1*h4*8.*COM(0.,1.)*M_PI*M_PI, conjeps1, T7);
cmult(aH1/sqrt(2.)/ang1a*h5*8.*COM(0.,1.)*M_PI*M_PI, epsa, T8);
cmult(aH1*aH1/2./ang1a/sqa1*h10*8.*COM(0.,1.)*M_PI*M_PI, pacur, T9);
cmult(-aH1*aH1/2./ang1a/sqa1*h12*8.*COM(0.,1.)*M_PI*M_PI, p1cur, T10);
current ans;
for(int i=0;i<4;i++)
{
ans[i] = T1[i]+T2[i]+T3[i]+T4[i]+T5[i]+T6[i]+T7[i]+T8[i]+T9[i]+T10[i];
}
retAns[0] = F/prop*ans[0];
retAns[1] = F/prop*ans[1];
retAns[2] = F/prop*ans[2];
retAns[3] = F/prop*ans[3];
}
/// @brief HNC amp for qg->qgH with finite top (i.e. j^{+-}_H)
void g_gH_HNC(HLV pa, HLV p1, HLV pH, double mq, current &retAns)
{
const double F = 4.*mq*mq/HEJ::vev;
COM ang1a,sqa1;
current conjepsH1,epsHa,p1cur,pacur,pHcur,conjeps1,epsa,paplusp1cur,
p1minuspacur,cur1a,cura1,epsHapart1,epsHapart2,conjepsH1part1,
conjepsH1part2;
// Find here if pa, meaning the gluon, is forward or backward
bool gluonforward = true;
if(pa.z() < 0)
gluonforward = false;
jio(pa,true,p1,true,cura1);
joi(p1,true,pa,true,cur1a);
to_current(pa,pacur);
to_current(p1,p1cur);
to_current(pH,pHcur);
to_current(pa+p1,paplusp1cur);
to_current(p1-pa,p1minuspacur);
const COM aH1 = cdot(pHcur,cura1);
const COM oneHa = std::conj(aH1); // = cdot(pHcur,cur1a)
if(gluonforward){
// sqrt(2pa_-/p1_-)*p1_perp/abs(p1_perp)
ang1a = sqrt(pa.plus()*p1.minus())*(p1.x()+COM(0.,1.)*p1.y())/p1.perp();
// sqrt(2pa_-/p1_-)*p1_perp*/abs(p1_perp)
sqa1 = sqrt(pa.plus()*p1.minus())*(p1.x()-COM(0.,1.)*p1.y())/p1.perp();
}
else {
ang1a = sqrt(pa.minus()*p1.plus());
sqa1 = sqrt(pa.minus()*p1.plus());
}
const double prop = (pa-p1-pH).m2();
cmult(1./sqrt(2)/sqa1, cur1a, epsa);
cmult(-1./sqrt(2)/sqa1, cura1, conjeps1);
const COM phase = cdot(conjeps1, epsa);
const COM Fta = FT(-pa,pa-pH,mq)/(pa-pH).m2();
const COM Ft1 = FT(-p1-pH,p1,mq)/(p1+pH).m2();
const COM Falpha = FT(p1-pa,pa-p1-pH,mq);
const COM Fbeta = FL(p1-pa,pa-p1-pH,mq);
const COM h1 = H1(p1,-pa, pH, mq);
const COM h2 = H2(p1,-pa, pH, mq);
const COM h4 = H4(p1,-pa, pH, mq);
const COM h5 = H5(p1,-pa, pH, mq);
const COM h10 = H10(p1,-pa, pH, mq);
const COM h12 = H12(p1,-pa, pH, mq);
cmult(Fta*pa.dot(pH), epsa, epsHapart1);
cmult(-1.*Fta*cdot(pHcur,epsa), pacur, epsHapart2);
cmult(Ft1*cdot(pHcur,conjeps1), p1cur, conjepsH1part1);
cmult(-Ft1*p1.dot(pH), conjeps1, conjepsH1part2);
cadd(epsHapart1, epsHapart2, epsHa);
cadd(conjepsH1part1, conjepsH1part2, conjepsH1);
current T1,T2,T3,T4,T5a,T5b,T6,T7,T8a,T8b,T9,T10,T11a,
T11b,T12a,T12b,T13;
if(gluonforward){
cmult(sqrt(2.)*sqrt(p1.plus()/pa.plus())*prop/sqa1, conjepsH1, T1);
cmult(-sqrt(2.)*sqrt(pa.plus()/p1.plus())*prop/sqa1, epsHa, T2);
}
else{
cmult(-sqrt(2.)*sqrt(p1.minus()/pa.minus())*((p1.x()-COM(0.,1.)*p1.y())/p1.perp())
*prop/sqa1, conjepsH1, T1);
cmult(sqrt(2.)*sqrt(pa.minus()/p1.minus())*((p1.x()+COM(0.,1.)*p1.y())/p1.perp())
*prop/sqa1, epsHa, T2);
}
const COM boxdiagFact = 8.*COM(0.,1.)*M_PI*M_PI;
cmult(aH1*sqrt(2.)/sqa1, epsHa, T3);
cmult(oneHa*sqrt(2.)/sqa1, conjepsH1, T4);
cmult(-2.*phase*Fta*pa.dot(pH), p1cur, T5a);
cmult(2.*phase*Ft1*p1.dot(pH), pacur, T5b);
cmult(-sqrt(2.)*Fta*p1.dot(pa)*oneHa/sqa1, conjeps1, T6);
cmult(-sqrt(2.)*Ft1*pa.dot(p1)*aH1/sqa1, epsa, T7);
cmult(-boxdiagFact*phase*h2, pacur, T8a);
cmult(boxdiagFact*phase*h1, p1cur, T8b);
cmult(boxdiagFact*aH1/sqrt(2.)/sqa1*h5, epsa, T9);
cmult(-boxdiagFact*oneHa/sqrt(2.)/sqa1*h4, conjeps1, T10);
cmult(boxdiagFact*aH1*oneHa/2./sqa1/sqa1*h10, pacur, T11a);
cmult(-boxdiagFact*aH1*oneHa/2./sqa1/sqa1*h12, p1cur, T11b);
cmult(-phase/(pa-p1).m2()*Falpha*(p1-pa).dot(pa-p1-pH), paplusp1cur, T12a);
cmult(phase/(pa-p1).m2()*Falpha*(pa+p1).dot(pa-p1-pH), p1minuspacur, T12b);
cmult(-phase*Fbeta*(pa-p1-pH).m2(), paplusp1cur, T13);
current ans;
for(int i=0;i<4;i++)
{
ans[i] = T1[i]+T2[i]+T3[i]+T4[i]+T5a[i]+T5b[i]+T6[i]+T7[i]+T8a[i]+T8b[i]
+T9[i]+T10[i]+T11a[i]+T11b[i]+T12a[i]+T12b[i]+T13[i];
}
retAns[0] = F/prop*ans[0];
retAns[1] = F/prop*ans[1];
retAns[2] = F/prop*ans[2];
retAns[3] = F/prop*ans[3];
}
} // namespace anonymous
// JDC - new amplitude with Higgs emitted close to gluon with full mt effects.
// Keep usual HEJ-style function call
double ME_Houtside_gq(HLV p1out, HLV p1in, HLV p2out, HLV p2in, HLV pH,
double mq, bool includeBottom, double mq2
){
current cur2bplus,cur2bminus, cur2bplusFlip, cur2bminusFlip;
current retAns,retAnsb;
joi(p2out,true,p2in,true,cur2bplus);
joi(p2out,false,p2in,false,cur2bminus);
joi(ParityFlip(p2out),true,ParityFlip(p2in),true,cur2bplusFlip);
joi(ParityFlip(p2out),false,ParityFlip(p2in),false,cur2bminusFlip);
COM app1,app2,apm1,apm2;
COM app3, app4, apm3, apm4;
if(!includeBottom)
{
g_gH_HC(p1in,p1out,pH,mq,retAns);
app1=cdot(retAns,cur2bplus);
app2=cdot(retAns,cur2bminus);
g_gH_HC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq,retAns);
app3=cdot(retAns,cur2bplusFlip);
app4=cdot(retAns,cur2bminusFlip);
// And non-conserving bits
g_gH_HNC(p1in,p1out,pH,mq,retAns);
apm1=cdot(retAns,cur2bplus);
apm2=cdot(retAns,cur2bminus);
g_gH_HNC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq,retAns);
apm3=cdot(retAns,cur2bplusFlip);
apm4=cdot(retAns,cur2bminusFlip);
} else {
g_gH_HC(p1in,p1out,pH,mq,retAns);
g_gH_HC(p1in,p1out,pH,mq2,retAnsb);
app1=cdot(retAns,cur2bplus) + cdot(retAnsb,cur2bplus);
app2=cdot(retAns,cur2bminus) + cdot(retAnsb,cur2bminus);
g_gH_HC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq,retAns);
g_gH_HC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq2,retAnsb);
app3=cdot(retAns,cur2bplusFlip) + cdot(retAnsb,cur2bplusFlip);
app4=cdot(retAns,cur2bminusFlip) + cdot(retAnsb,cur2bminusFlip);
// And non-conserving bits
g_gH_HNC(p1in,p1out,pH,mq,retAns);
g_gH_HNC(p1in,p1out,pH,mq2,retAnsb);
apm1=cdot(retAns,cur2bplus) + cdot(retAnsb,cur2bplus);
apm2=cdot(retAns,cur2bminus) + cdot(retAnsb,cur2bminus);
g_gH_HNC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq,retAns);
g_gH_HNC(ParityFlip(p1in),ParityFlip(p1out),ParityFlip(pH),mq2,retAnsb);
apm3=cdot(retAns,cur2bplusFlip) + cdot(retAnsb,cur2bplusFlip);
apm4=cdot(retAns,cur2bminusFlip) + cdot(retAnsb,cur2bminusFlip);
}
return abs2(app1) + abs2(app2) + abs2(app3) + abs2(app4) + abs2(apm1)
+ abs2(apm2) + abs2(apm3) + abs2(apm4);
}
#endif // HEJ_BUILD_WITH_QCDLOOP
double C2gHgm(HLV p2, HLV p1, HLV pH)
{
static double A=1./(3.*M_PI*HEJ::vev);
// Implements Eq. (4.22) in hep-ph/0301013 with modifications to incoming plus momenta
double s12,p1p,p2p;
COM p1perp,p3perp,phperp;
// Determine first whether this is the case p1p\sim php>>p3p or the opposite
s12=p1.invariantMass2(-p2);
if (p2.pz()>0.) { // case considered in hep-ph/0301013
p1p=p1.plus();
p2p=p2.plus();
} else { // opposite case
p1p=p1.minus();
p2p=p2.minus();
}
p1perp=p1.px()+COM(0,1)*p1.py();
phperp=pH.px()+COM(0,1)*pH.py();
p3perp=-(p1perp+phperp);
COM temp=COM(0,1)*A/(2.*s12)*(p2p/p1p*conj(p1perp)*p3perp+p1p/p2p*p1perp*conj(p3perp));
temp=temp*conj(temp);
return temp.real();
}
double C2gHgp(HLV p2, HLV p1, HLV pH)
{
static double A=1./(3.*M_PI*HEJ::vev);
// Implements Eq. (4.23) in hep-ph/0301013
double s12,php,p1p,phm;
COM p1perp,p3perp,phperp;
// Determine first whether this is the case p1p\sim php>>p3p or the opposite
s12=p1.invariantMass2(-p2);
if (p2.pz()>0.) { // case considered in hep-ph/0301013
php=pH.plus();
phm=pH.minus();
p1p=p1.plus();
} else { // opposite case
php=pH.minus();
phm=pH.plus();
p1p=p1.minus();
}
p1perp=p1.px()+COM(0,1)*p1.py();
phperp=pH.px()+COM(0,1)*pH.py();
p3perp=-(p1perp+phperp);
COM temp=-COM(0,1)*A/(2.*s12)*( conj(p1perp*p3perp)*pow(php/p1p,2)/(1.+php/p1p)
+s12*(pow(conj(phperp),2)/(pow(abs(phperp),2)+p1p*phm)
-pow(conj(p3perp)
+(1.+php/p1p)*conj(p1perp),2)/((1.+php/p1p)*(pH.m2()+2.*p1.dot(pH)))) );
temp=temp*conj(temp);
return temp.real();
}
double C2qHqm(HLV p2, HLV p1, HLV pH)
{
static double A=1./(3.*M_PI*HEJ::vev);
// Implements Eq. (4.22) in hep-ph/0301013
double s12,p2p,p1p;
COM p1perp,p3perp,phperp;
// Determine first whether this is the case p1p\sim php>>p3p or the opposite
s12=p1.invariantMass2(-p2);
if (p2.pz()>0.) { // case considered in hep-ph/0301013
p2p=p2.plus();
p1p=p1.plus();
} else { // opposite case
p2p=p2.minus();
p1p=p1.minus();
}
p1perp=p1.px()+COM(0,1)*p1.py();
phperp=pH.px()+COM(0,1)*pH.py();
p3perp=-(p1perp+phperp);
COM temp=A/(2.*s12)*( sqrt(p2p/p1p)*p3perp*conj(p1perp)
+sqrt(p1p/p2p)*p1perp*conj(p3perp) );
temp=temp*conj(temp);
return temp.real();
}
diff --git a/src/MatrixElement.cc b/src/MatrixElement.cc
index a4aaaa5..259b2e2 100644
--- a/src/MatrixElement.cc
+++ b/src/MatrixElement.cc
@@ -1,1728 +1,1728 @@
/**
* \authors The HEJ collaboration (see AUTHORS for details)
* \date 2019
* \copyright GPLv2 or later
*/
#include "HEJ/MatrixElement.hh"
#include <algorithm>
#include <assert.h>
#include <limits>
#include <math.h>
#include <stddef.h>
#include <unordered_map>
#include <utility>
#include "CLHEP/Vector/LorentzVector.h"
#include "fastjet/ClusterSequence.hh"
#include "HEJ/Constants.hh"
#include "HEJ/Wjets.hh"
#include "HEJ/Hjets.hh"
#include "HEJ/jets.hh"
#include "HEJ/PDG_codes.hh"
#include "HEJ/event_types.hh"
#include "HEJ/Event.hh"
#include "HEJ/exceptions.hh"
#include "HEJ/Particle.hh"
#include "HEJ/utility.hh"
namespace HEJ{
double MatrixElement::omega0(
double alpha_s, double mur,
fastjet::PseudoJet const & q_j
) const {
const double lambda = param_.regulator_lambda;
const double result = - alpha_s*N_C/M_PI*log(q_j.perp2()/(lambda*lambda));
if(! param_.log_correction) return result;
// use alpha_s(sqrt(q_j*lambda)), evolved to mur
return (
1. + alpha_s/(4.*M_PI)*beta0*log(mur*mur/(q_j.perp()*lambda))
)*result;
}
Weights MatrixElement::operator()(Event const & event) const {
return tree(event)*virtual_corrections(event);
}
Weights MatrixElement::tree(Event const & event) const {
return tree_param(event)*tree_kin(event);
}
Weights MatrixElement::tree_param(Event const & event) const {
if(! is_resummable(event.type())) {
return Weights{0., std::vector<double>(event.variations().size(), 0.)};
}
Weights result;
// only compute once for each renormalisation scale
std::unordered_map<double, double> known;
result.central = tree_param(event, event.central().mur);
known.emplace(event.central().mur, result.central);
for(auto const & var: event.variations()) {
const auto ME_it = known.find(var.mur);
if(ME_it == end(known)) {
const double wt = tree_param(event, var.mur);
result.variations.emplace_back(wt);
known.emplace(var.mur, wt);
}
else {
result.variations.emplace_back(ME_it->second);
}
}
return result;
}
Weights MatrixElement::virtual_corrections(Event const & event) const {
if(! is_resummable(event.type())) {
return Weights{0., std::vector<double>(event.variations().size(), 0.)};
}
Weights result;
// only compute once for each renormalisation scale
std::unordered_map<double, double> known;
result.central = virtual_corrections(event, event.central().mur);
known.emplace(event.central().mur, result.central);
for(auto const & var: event.variations()) {
const auto ME_it = known.find(var.mur);
if(ME_it == end(known)) {
const double wt = virtual_corrections(event, var.mur);
result.variations.emplace_back(wt);
known.emplace(var.mur, wt);
}
else {
result.variations.emplace_back(ME_it->second);
}
}
return result;
}
double MatrixElement::virtual_corrections_W(
Event const & event,
double mur,
Particle const & WBoson
) const{
auto const & in = event.incoming();
const auto partons = filter_partons(event.outgoing());
fastjet::PseudoJet const & pa = in.front().p;
#ifndef NDEBUG
fastjet::PseudoJet const & pb = in.back().p;
double const norm = (in.front().p + in.back().p).E();
#endif
assert(std::is_sorted(partons.begin(), partons.end(), rapidity_less{}));
assert(partons.size() >= 2);
assert(pa.pz() < pb.pz());
fastjet::PseudoJet q = pa - partons[0].p;
size_t first_idx = 0;
size_t last_idx = partons.size() - 1;
bool wc = true;
bool wqq = false;
// With extremal qqx or unordered gluon outside the extremal
// partons then it is not part of the FKL ladder and does not
// contribute to the virtual corrections. W emitted from the
// most backward leg must be taken into account in t-channel
if (event.type() == event_type::FKL) {
if (in[0].type != partons[0].type ){
q -= WBoson.p;
wc = false;
}
}
else if (event.type() == event_type::unob) {
q -= partons[1].p;
++first_idx;
if (in[0].type != partons[1].type ){
q -= WBoson.p;
wc = false;
}
}
else if (event.type() == event_type::qqxexb) {
q -= partons[1].p;
++first_idx;
if (abs(partons[0].type) != abs(partons[1].type)){
q -= WBoson.p;
wc = false;
}
}
if(event.type() == event_type::unof
|| event.type() == event_type::qqxexf){
--last_idx;
}
size_t first_idx_qqx = last_idx;
size_t last_idx_qqx = last_idx;
//if qqxMid event, virtual correction do not occur between
//qqx pair.
if(event.type() == event_type::qqxmid){
const auto backquark = std::find_if(
begin(partons) + 1, end(partons) - 1 ,
[](Particle const & s){ return (s.type != pid::gluon); }
);
if(backquark == end(partons) || (backquark+1)->type==pid::gluon) return 0;
if(abs(backquark->type) != abs((backquark+1)->type)) {
wqq=true;
wc=false;
}
last_idx = std::distance(begin(partons), backquark);
first_idx_qqx = last_idx+1;
}
double exponent = 0;
const double alpha_s = alpha_s_(mur);
for(size_t j = first_idx; j < last_idx; ++j){
exponent += omega0(alpha_s, mur, q)*(
partons[j+1].rapidity() - partons[j].rapidity()
);
q -=partons[j+1].p;
} // End Loop one
if (last_idx != first_idx_qqx) q -= partons[last_idx+1].p;
if (wqq) q -= WBoson.p;
for(size_t j = first_idx_qqx; j < last_idx_qqx; ++j){
exponent += omega0(alpha_s, mur, q)*(
partons[j+1].rapidity() - partons[j].rapidity()
);
q -= partons[j+1].p;
}
if (wc) q -= WBoson.p;
assert(
nearby(q, -1*pb, norm)
|| is_AWZH_boson(partons.back().type)
|| event.type() == event_type::unof
|| event.type() == event_type::qqxexf
);
return exp(exponent);
}
double MatrixElement::virtual_corrections(
Event const & event,
double mur
) const{
auto const & in = event.incoming();
auto const & out = event.outgoing();
fastjet::PseudoJet const & pa = in.front().p;
#ifndef NDEBUG
fastjet::PseudoJet const & pb = in.back().p;
double const norm = (in.front().p + in.back().p).E();
#endif
const auto AWZH_boson = std::find_if(
begin(out), end(out),
[](Particle const & p){ return is_AWZH_boson(p); }
);
if(AWZH_boson != end(out) && abs(AWZH_boson->type) == pid::Wp){
return virtual_corrections_W(event, mur, *AWZH_boson);
}
assert(std::is_sorted(out.begin(), out.end(), rapidity_less{}));
assert(out.size() >= 2);
assert(pa.pz() < pb.pz());
fastjet::PseudoJet q = pa - out[0].p;
size_t first_idx = 0;
size_t last_idx = out.size() - 1;
// if there is a Higgs boson, extremal qqx or unordered gluon
// outside the extremal partons then it is not part of the FKL
// ladder and does not contribute to the virtual corrections
if((out.front().type == pid::Higgs)
|| event.type() == event_type::unob
|| event.type() == event_type::qqxexb){
q -= out[1].p;
++first_idx;
}
if((out.back().type == pid::Higgs)
|| event.type() == event_type::unof
|| event.type() == event_type::qqxexf){
--last_idx;
}
size_t first_idx_qqx = last_idx;
size_t last_idx_qqx = last_idx;
//if qqxMid event, virtual correction do not occur between
//qqx pair.
if(event.type() == event_type::qqxmid){
const auto backquark = std::find_if(
begin(out) + 1, end(out) - 1 ,
[](Particle const & s){ return (s.type != pid::gluon && is_parton(s.type)); }
);
if(backquark == end(out) || (backquark+1)->type==pid::gluon) return 0;
last_idx = std::distance(begin(out), backquark);
first_idx_qqx = last_idx+1;
}
double exponent = 0;
const double alpha_s = alpha_s_(mur);
for(size_t j = first_idx; j < last_idx; ++j){
exponent += omega0(alpha_s, mur, q)*(
out[j+1].rapidity() - out[j].rapidity()
);
q -= out[j+1].p;
}
if (last_idx != first_idx_qqx) q -= out[last_idx+1].p;
for(size_t j = first_idx_qqx; j < last_idx_qqx; ++j){
exponent += omega0(alpha_s, mur, q)*(
out[j+1].rapidity() - out[j].rapidity()
);
q -= out[j+1].p;
}
assert(
nearby(q, -1*pb, norm)
|| out.back().type == pid::Higgs
|| event.type() == event_type::unof
|| event.type() == event_type::qqxexf
);
return exp(exponent);
}
} // namespace HEJ
namespace {
//! Lipatov vertex for partons emitted into extremal jets
double C2Lipatov(
CLHEP::HepLorentzVector const & qav,
CLHEP::HepLorentzVector const & qbv,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & p2
){
CLHEP::HepLorentzVector temptrans=-(qav+qbv);
CLHEP::HepLorentzVector p5=qav-qbv;
CLHEP::HepLorentzVector CL=temptrans
+ p1*(qav.m2()/p5.dot(p1) + 2.*p5.dot(p2)/p1.dot(p2))
- p2*(qbv.m2()/p5.dot(p2) + 2.*p5.dot(p1)/p1.dot(p2));
return -CL.dot(CL);
}
//! Lipatov vertex with soft subtraction for partons emitted into extremal jets
double C2Lipatovots(
CLHEP::HepLorentzVector const & qav,
CLHEP::HepLorentzVector const & qbv,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & p2,
double lambda
) {
double kperp=(qav-qbv).perp();
if (kperp>lambda)
return C2Lipatov(qav, qbv, p1, p2)/(qav.m2()*qbv.m2());
double Cls=(C2Lipatov(qav, qbv, p1, p2)/(qav.m2()*qbv.m2()));
return Cls-4./(kperp*kperp);
}
//! Lipatov vertex
double C2Lipatov( // B
CLHEP::HepLorentzVector const & qav,
CLHEP::HepLorentzVector const & qbv,
CLHEP::HepLorentzVector const & pim,
CLHEP::HepLorentzVector const & pip,
CLHEP::HepLorentzVector const & pom,
CLHEP::HepLorentzVector const & pop
){
CLHEP::HepLorentzVector temptrans=-(qav+qbv);
CLHEP::HepLorentzVector p5=qav-qbv;
CLHEP::HepLorentzVector CL=temptrans
+ qav.m2()*(1./p5.dot(pip)*pip + 1./p5.dot(pop)*pop)/2.
- qbv.m2()*(1./p5.dot(pim)*pim + 1./p5.dot(pom)*pom)/2.
+ ( pip*(p5.dot(pim)/pip.dot(pim) + p5.dot(pom)/pip.dot(pom))
+ pop*(p5.dot(pim)/pop.dot(pim) + p5.dot(pom)/pop.dot(pom))
- pim*(p5.dot(pip)/pip.dot(pim) + p5.dot(pop)/pop.dot(pim))
- pom*(p5.dot(pip)/pip.dot(pom) + p5.dot(pop)/pop.dot(pom)) )/2.;
return -CL.dot(CL);
}
//! Lipatov vertex with soft subtraction
double C2Lipatovots(
CLHEP::HepLorentzVector const & qav,
CLHEP::HepLorentzVector const & qbv,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & p2,
double lambda
) {
double kperp=(qav-qbv).perp();
if (kperp>lambda)
return C2Lipatov(qav, qbv, pa, pb, p1, p2)/(qav.m2()*qbv.m2());
double Cls=(C2Lipatov(qav, qbv, pa, pb, p1, p2)/(qav.m2()*qbv.m2()));
double temp=Cls-4./(kperp*kperp);
return temp;
}
/** Matrix element squared for tree-level current-current scattering
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @returns ME Squared for Tree-Level Current-Current Scattering
*/
double ME_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa
){
if (aptype==21&&bptype==21) {
return ME_gg(pn,pb,p1,pa);
} else if (aptype==21&&bptype!=21) {
if (bptype > 0)
return ME_qg(pn,pb,p1,pa);
else
return ME_qbarg(pn,pb,p1,pa);
}
else if (bptype==21&&aptype!=21) { // ----- || -----
if (aptype > 0)
return ME_qg(p1,pa,pn,pb);
else
return ME_qbarg(p1,pa,pn,pb);
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
return ME_qQ(pn,pb,p1,pa);
else
return ME_qQbar(pn,pb,p1,pa);
}
else {
if (aptype>0)
return ME_qQbar(p1,pa,pn,pb);
else
return ME_qbarQbar(pn,pb,p1,pa);
}
}
throw std::logic_error("unknown particle types");
}
/** Matrix element squared for tree-level current-current scattering With W+Jets
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param wc Boolean. True->W Emitted from b. Else; emitted from leg a
* @returns ME Squared for Tree-Level Current-Current Scattering
*/
double ME_W_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wc
){
// We know it cannot be gg incoming.
assert(!(aptype==21 && bptype==21));
if (aptype==21&&bptype!=21) {
if (bptype > 0)
return ME_W_qg(pn,plbar,pl,pb,p1,pa);
else
return ME_W_qbarg(pn,plbar,pl,pb,p1,pa);
}
else if (bptype==21&&aptype!=21) { // ----- || -----
if (aptype > 0)
return ME_W_qg(p1,plbar,pl,pa,pn,pb);
else
return ME_W_qbarg(p1,plbar,pl,pa,pn,pb);
}
else { // they are both quark
if (wc==true){ // emission off b, (first argument pbout)
if (bptype>0) {
if (aptype>0)
return ME_W_qQ(pn,plbar,pl,pb,p1,pa);
else
return ME_W_qQbar(pn,plbar,pl,pb,p1,pa);
}
else {
if (aptype>0)
return ME_W_qbarQ(pn,plbar,pl,pb,p1,pa);
else
return ME_W_qbarQbar(pn,plbar,pl,pb,p1,pa);
}
}
else{ // emission off a, (first argument paout)
if (aptype > 0) {
if (bptype > 0)
return ME_W_qQ(p1,plbar,pl,pa,pn,pb);
else
return ME_W_qQbar(p1,plbar,pl,pa,pn,pb);
}
else { // a is anti-quark
if (bptype > 0)
return ME_W_qbarQ(p1,plbar,pl,pa,pn,pb);
else
return ME_W_qbarQbar(p1,plbar,pl,pa,pn,pb);
}
}
}
throw std::logic_error("unknown particle types");
}
/** Matrix element squared for backwards uno tree-level current-current
* scattering With W+Jets
*
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param pg Unordered gluon momentum
* @param wc Boolean. True->W Emitted from b. Else; emitted from leg a
* @returns ME Squared for unob Tree-Level Current-Current Scattering
*/
double ME_W_unob_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pg,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wc
){
// we know they are not both gluons
if (bptype == 21 && aptype != 21) { // b gluon => W emission off a
if (aptype > 0)
return ME_Wuno_qg(p1,pa,pn,pb,pg,plbar,pl);
else
return ME_Wuno_qbarg(p1,pa,pn,pb,pg,plbar,pl);
}
else { // they are both quark
if (wc) {// emission off b, i.e. b is first current
if (bptype>0){
if (aptype>0)
return ME_W_unob_qQ(p1,pa,pn,pb,pg,plbar,pl);
else
return ME_W_unob_qQbar(p1,pa,pn,pb,pg,plbar,pl);
}
else{
if (aptype>0)
return ME_W_unob_qbarQ(p1,pa,pn,pb,pg,plbar,pl);
else
return ME_W_unob_qbarQbar(p1,pa,pn,pb,pg,plbar,pl);
}
}
else {// wc == false, emission off a, i.e. a is first current
if (aptype > 0) {
if (bptype > 0) //qq
return ME_Wuno_qQ(p1,pa,pn,pb,pg,plbar,pl);
else //qqbar
return ME_Wuno_qQbar(p1,pa,pn,pb,pg,plbar,pl);
}
else { // a is anti-quark
if (bptype > 0) //qbarq
return ME_Wuno_qbarQ(p1,pa,pn,pb,pg,plbar,pl);
else //qbarqbar
return ME_Wuno_qbarQbar(p1,pa,pn,pb,pg,plbar,pl);
}
}
}
throw std::logic_error("unknown particle types");
}
/** Matrix element squared for uno forward tree-level current-current
* scattering With W+Jets
*
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param pg Unordered gluon momentum
* @param wc Boolean. True->W Emitted from b. Else; emitted from leg a
* @returns ME Squared for unof Tree-Level Current-Current Scattering
*/
double ME_W_unof_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pg,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wc
){
// we know they are not both gluons
if (aptype==21 && bptype!=21) {//a gluon => W emission off b
if (bptype > 0)
return ME_Wuno_qg(pn, pb, p1, pa, pg, plbar, pl);
else
return ME_Wuno_qbarg(pn, pb, p1, pa, pg, plbar, pl);
}
else { // they are both quark
if (wc) {// emission off b, i.e. b is first current
if (bptype>0){
if (aptype>0)
return ME_Wuno_qQ(pn, pb, p1, pa, pg, plbar, pl);
else
return ME_Wuno_qQbar(pn, pb, p1, pa, pg, plbar, pl);
}
else{
if (aptype>0)
return ME_Wuno_qbarQ(pn, pb, p1, pa, pg, plbar, pl);
else
return ME_Wuno_qbarQbar(pn, pb, p1, pa, pg, plbar, pl);
}
}
else {// wc == false, emission off a, i.e. a is first current
if (aptype > 0) {
if (bptype > 0) //qq
return ME_W_unof_qQ(p1, pa, pn, pb, pg, plbar, pl);
// return ME_W_unof_qQ(pn,pb,p1,pa,pg,plbar,pl);
else //qqbar
return ME_W_unof_qQbar(p1, pa, pn, pb, pg, plbar, pl);
}
else { // a is anti-quark
if (bptype > 0) //qbarq
return ME_W_unof_qbarQ(p1, pa, pn, pb, pg, plbar, pl);
else //qbarqbar
return ME_W_unof_qbarQbar(p1, pa, pn, pb, pg, plbar, pl);
}
}
}
throw std::logic_error("unknown particle types");
}
/** \brief Matrix element squared for backward qqx tree-level current-current
* scattering With W+Jets
*
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pa Initial state a Momentum
* @param pb Initial state b Momentum
* @param pq Final state q Momentum
* @param pqbar Final state qbar Momentum
* @param pn Final state n Momentum
* @param plbar Final state anti-lepton momentum
* @param pl Final state lepton momentum
* @param wc Boolean. True->W Emitted from b. Else; emitted from leg a
* @returns ME Squared for qqxb Tree-Level Current-Current Scattering
*/
double ME_W_qqxb_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & pq,
CLHEP::HepLorentzVector const & pqbar,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wc
){
// CAM factors for the qqx amps, and qqbar ordering (default, qbar extremal)
bool swapQuarkAntiquark=false;
double CFbackward;
if (pqbar.rapidity() > pq.rapidity()){
swapQuarkAntiquark=true;
CFbackward = (0.5*(3.-1./3.)*(pa.minus()/(pq.minus())+(pq.minus())/pa.minus())+1./3.)*3./4.;
}
else{
CFbackward = (0.5*(3.-1./3.)*(pa.minus()/(pqbar.minus())+(pqbar.minus())/pa.minus())+1./3.)*3./4.;
}
// With qqbar we could have 2 incoming gluons and W Emission
if (aptype==21&&bptype==21) {//a gluon, b gluon gg->qqbarWg
// This will be a wqqx emission as there is no other possible W Emission Site.
if (swapQuarkAntiquark)
return ME_WExqqx_qqbarg(pa, pqbar, plbar, pl, pq, pn, pb)*CFbackward;
else
return ME_WExqqx_qbarqg(pa, pq, plbar, pl, pqbar, pn, pb)*CFbackward;
}
else if (aptype==21&&bptype!=21 ) {//a gluon => W emission off b leg or qqx
if (!wc){ // W Emitted from backwards qqx
if (swapQuarkAntiquark)
return ME_WExqqx_qqbarQ(pa, pqbar, plbar, pl, pq, pn, pb)*CFbackward;
else
return ME_WExqqx_qbarqQ(pa, pq, plbar, pl, pqbar, pn, pb)*CFbackward;
}
else { // W Must be emitted from forwards leg.
if(bptype > 0){
if (swapQuarkAntiquark)
return ME_W_Exqqx_QQq(pb, pa, pn, pqbar, pq, plbar, pl, false)*CFbackward;
else
return ME_W_Exqqx_QQq(pb, pa, pn, pq, pqbar, plbar, pl, false)*CFbackward;
} else {
if (swapQuarkAntiquark)
return ME_W_Exqqx_QQq(pb, pa, pn, pqbar, pq, plbar, pl, true)*CFbackward;
else
return ME_W_Exqqx_QQq(pb, pa, pn, pq, pqbar, plbar, pl, true)*CFbackward;
}
}
}
throw std::logic_error("Incompatible incoming particle types with qqxb");
}
/* \brief Matrix element squared for forward qqx tree-level current-current
* scattering With W+Jets
*
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pa Initial state a Momentum
* @param pb Initial state b Momentum
* @param pq Final state q Momentum
* @param pqbar Final state qbar Momentum
* @param p1 Final state 1 Momentum
* @param plbar Final state anti-lepton momentum
* @param pl Final state lepton momentum
* @param wc Boolean. True->W Emitted from b. Else; emitted from leg a
* @returns ME Squared for qqxf Tree-Level Current-Current Scattering
*/
double ME_W_qqxf_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & pq,
CLHEP::HepLorentzVector const & pqbar,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wc
){
// CAM factors for the qqx amps, and qqbar ordering (default, qbar extremal)
bool swapQuarkAntiquark=false;
double CFforward;
if (pqbar.rapidity() < pq.rapidity()){
swapQuarkAntiquark=true;
CFforward = (0.5*(3.-1./3.)*(pb.plus()/(pq.plus())+(pq.plus())/pb.plus())+1./3.)*3./4.;
}
else{
CFforward = (0.5*(3.-1./3.)*(pb.plus()/(pqbar.plus())+(pqbar.plus())/pb.plus())+1./3.)*3./4.;
}
// With qqbar we could have 2 incoming gluons and W Emission
if (aptype==21&&bptype==21) {//a gluon, b gluon gg->qqbarWg
// This will be a wqqx emission as there is no other possible W Emission Site.
if (swapQuarkAntiquark)
return ME_WExqqx_qqbarg(pb, pqbar, plbar, pl, pq, p1, pa)*CFforward;
else
return ME_WExqqx_qbarqg(pb, pq, plbar, pl, pqbar, p1, pa)*CFforward;
}
else if (bptype==21&&aptype!=21) {// b gluon => W emission off a or qqx
if (wc){ // W Emitted from forwards qqx
if (swapQuarkAntiquark)
return ME_WExqqx_qqbarQ(pb, pqbar, plbar, pl, pq, p1, pa)*CFforward;
else
return ME_WExqqx_qbarqQ(pb, pq, plbar, pl, pqbar, p1, pa)*CFforward;
}
// W Must be emitted from backwards leg.
if (aptype > 0){
if (swapQuarkAntiquark)
return ME_W_Exqqx_QQq(pa, pb, p1, pqbar, pq, plbar, pl, false)*CFforward;
else
return ME_W_Exqqx_QQq(pa, pb, p1, pq, pqbar, plbar, pl, false)*CFforward;
} else {
if (swapQuarkAntiquark)
return ME_W_Exqqx_QQq(pa, pb, p1, pqbar, pq, plbar, pl, true)*CFforward;
else
return ME_W_Exqqx_QQq(pa, pb, p1, pq, pqbar, plbar, pl, true)*CFforward;
}
}
throw std::logic_error("Incompatible incoming particle types with qqxf");
}
/* \brief Matrix element squared for central qqx tree-level current-current
* scattering With W+Jets
*
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param nabove Number of gluons emitted before central qqxpair
* @param nbelow Number of gluons emitted after central qqxpair
* @param pa Initial state a Momentum
* @param pb Initial state b Momentum\
* @param pq Final state qbar Momentum
* @param pqbar Final state q Momentum
* @param partons Vector of all outgoing partons
* @param plbar Final state anti-lepton momentum
* @param pl Final state lepton momentum
* @param wqq Boolean. True siginfies W boson is emitted from Central qqx
* @param wc Boolean. wc=true signifies w boson emitted from leg b; if wqq=false.
* @returns ME Squared for qqxmid Tree-Level Current-Current Scattering
*/
double ME_W_qqxmid_current(
int aptype, int bptype,
int nabove, int nbelow,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & pq,
CLHEP::HepLorentzVector const & pqbar,
std::vector<HLV> const & partons,
CLHEP::HepLorentzVector const & plbar,
CLHEP::HepLorentzVector const & pl,
bool const wqq, bool const wc
){
// CAM factors for the qqx amps, and qqbar ordering (default, pq backwards)
bool swapQuarkAntiquark=false;
if (pqbar.rapidity() < pq.rapidity()){
swapQuarkAntiquark=true;
}
double wt=1.;
if (aptype==21) wt*=K_g(partons.front(),pa)/HEJ::C_F;
if (bptype==21) wt*=K_g(partons.back(),pb)/HEJ::C_F;
if (aptype <=0 && bptype <=0){ // Both External AntiQuark
if (wqq==1){//emission from central qqbar
return wt*ME_WCenqqx_qq(pa, pb, pl, plbar, partons,true,true,
swapQuarkAntiquark, nabove);
}
else if (wc==1){//emission from b leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, true,true,
swapQuarkAntiquark, nabove, nbelow, true);
}
else { // emission from a leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl,plbar, partons, true,true,
swapQuarkAntiquark, nabove, nbelow, false);
}
} // end both antiquark
else if (aptype<=0){ // a is antiquark
if (wqq==1){//emission from central qqbar
return wt*ME_WCenqqx_qq(pa, pb, pl, plbar, partons, false, true,
swapQuarkAntiquark, nabove);
}
else if (wc==1){//emission from b leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons,false,true,
swapQuarkAntiquark, nabove, nbelow, true);
}
else { // emission from a leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, false, true,
swapQuarkAntiquark, nabove, nbelow, false);
}
} // end a is antiquark
else if (bptype<=0){ // b is antiquark
if (wqq==1){//emission from central qqbar
return wt*ME_WCenqqx_qq(pa, pb, pl, plbar, partons, true, false,
swapQuarkAntiquark, nabove);
}
else if (wc==1){//emission from b leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, true, false,
swapQuarkAntiquark, nabove, nbelow, true);
}
else { // emission from a leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, true, false,
swapQuarkAntiquark, nabove, nbelow, false);
}
} //end b is antiquark
else{ //Both Quark or gluon
if (wqq==1){//emission from central qqbar
return wt*ME_WCenqqx_qq(pa, pb, pl, plbar, partons, false, false,
swapQuarkAntiquark, nabove);}
else if (wc==1){//emission from b leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, false, false,
swapQuarkAntiquark, nabove, nbelow, true);
}
else { // emission from a leg
return wt*ME_W_Cenqqx_qq(pa, pb, pl, plbar, partons, false, false,
swapQuarkAntiquark, nabove, nbelow, false);
}
}
throw std::logic_error("unknown particle types");
}
/** \brief Matrix element squared for tree-level current-current scattering with Higgs
* @param aptype Particle a PDG ID
* @param bptype Particle b PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param qH t-channel momentum before Higgs
* @param qHp1 t-channel momentum after Higgs
* @returns ME Squared for Tree-Level Current-Current Scattering with Higgs
*/
double ME_Higgs_current(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & qH, // t-channel momentum before Higgs
CLHEP::HepLorentzVector const & qHp1, // t-channel momentum after Higgs
double mt, bool include_bottom, double mb
){
if (aptype==21&&bptype==21) // gg initial state
return ME_H_gg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else if (aptype==21&&bptype!=21) {
if (bptype > 0)
return ME_H_qg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4./9.;
else
return ME_H_qbarg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4./9.;
}
else if (bptype==21&&aptype!=21) {
if (aptype > 0)
return ME_H_qg(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4./9.;
else
return ME_H_qbarg(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4./9.;
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
return ME_H_qQ(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4.*4./(9.*9.);
else
return ME_H_qQbar(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4.*4./(9.*9.);
}
else {
if (aptype>0)
return ME_H_qQbar(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4.*4./(9.*9.);
else
return ME_H_qbarQbar(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4.*4./(9.*9.);
}
}
throw std::logic_error("unknown particle types");
}
/** \brief Current matrix element squared with Higgs and unordered forward emission
* @param aptype Particle A PDG ID
* @param bptype Particle B PDG ID
* @param punof Unordered Particle Momentum
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param qH t-channel momentum before Higgs
* @param qHp1 t-channel momentum after Higgs
* @returns ME Squared with Higgs and unordered forward emission
*/
double ME_Higgs_current_unof(
int aptype, int bptype,
CLHEP::HepLorentzVector const & punof,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & qH, // t-channel momentum before Higgs
CLHEP::HepLorentzVector const & qHp1, // t-channel momentum after Higgs
double mt, bool include_bottom, double mb
){
if (aptype==21&&bptype!=21) {
if (bptype > 0)
- return ME_H_unof_qg(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qg(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unof_qbarg(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qbarg(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
- return ME_H_unof_qQ(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qQ(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unof_qQbar(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qQbar(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
else {
if (aptype>0)
- return ME_H_unof_qbarQ(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qbarQ(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unof_qbarQbar(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unof_qbarQbar(punof,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
}
throw std::logic_error("unknown particle types");
}
/** \brief Current matrix element squared with Higgs and unordered backward emission
* @param aptype Particle A PDG ID
* @param bptype Particle B PDG ID
* @param pn Particle n Momentum
* @param pb Particle b Momentum
* @param punob Unordered back Particle Momentum
* @param p1 Particle 1 Momentum
* @param pa Particle a Momentum
* @param qH t-channel momentum before Higgs
* @param qHp1 t-channel momentum after Higgs
* @returns ME Squared with Higgs and unordered backward emission
*/
double ME_Higgs_current_unob(
int aptype, int bptype,
CLHEP::HepLorentzVector const & pn,
CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & punob,
CLHEP::HepLorentzVector const & p1,
CLHEP::HepLorentzVector const & pa,
CLHEP::HepLorentzVector const & qH, // t-channel momentum before Higgs
CLHEP::HepLorentzVector const & qHp1, // t-channel momentum after Higgs
double mt, bool include_bottom, double mb
){
if (bptype==21&&aptype!=21) {
if (aptype > 0)
- return ME_H_unob_gQ(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_gQ(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unob_gQbar(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_gQbar(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
else { // they are both quark
if (aptype>0) {
if (bptype>0)
- return ME_H_unob_qQ(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_qQ(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unob_qbarQ(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_qbarQ(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
else {
if (bptype>0)
- return ME_H_unob_qQbar(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_qQbar(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
else
- return ME_H_unob_qbarQbar(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
+ return ME_H_unob_qbarQbar(punob,p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb);
}
}
throw std::logic_error("unknown particle types");
}
CLHEP::HepLorentzVector to_HepLorentzVector(HEJ::Particle const & particle){
return {particle.p.px(), particle.p.py(), particle.p.pz(), particle.p.E()};
}
void validate(HEJ::MatrixElementConfig const & config) {
#ifndef HEJ_BUILD_WITH_QCDLOOP
if(!config.Higgs_coupling.use_impact_factors) {
throw std::invalid_argument{
"Invalid Higgs coupling settings.\n"
"HEJ without QCDloop support can only use impact factors.\n"
"Set use_impact_factors to true or recompile HEJ.\n"
};
}
#endif
if(config.Higgs_coupling.use_impact_factors
&& config.Higgs_coupling.mt != std::numeric_limits<double>::infinity()) {
throw std::invalid_argument{
"Conflicting settings: "
"impact factors may only be used in the infinite top mass limit"
};
}
}
} // namespace anonymous
namespace HEJ{
MatrixElement::MatrixElement(
std::function<double (double)> alpha_s,
MatrixElementConfig conf
):
alpha_s_{std::move(alpha_s)},
param_{std::move(conf)}
{
validate(param_);
}
double MatrixElement::tree_kin(
Event const & ev
) const {
if(! is_resummable(ev.type())) return 0.;
auto AWZH_boson = std::find_if(
begin(ev.outgoing()), end(ev.outgoing()),
[](Particle const & p){return is_AWZH_boson(p);}
);
if(AWZH_boson == end(ev.outgoing()))
return tree_kin_jets(ev);
switch(AWZH_boson->type){
case pid::Higgs:
return tree_kin_Higgs(ev);
case pid::Wp:
case pid::Wm:
return tree_kin_W(ev);
// TODO
case pid::photon:
case pid::Z:
default:
throw not_implemented("Emission of boson of unsupported type");
}
}
namespace{
constexpr int extremal_jet_idx = 1;
constexpr int no_extremal_jet_idx = 0;
bool treat_as_extremal(Particle const & parton){
return parton.p.user_index() == extremal_jet_idx;
}
template<class InputIterator>
double FKL_ladder_weight(
InputIterator begin_gluon, InputIterator end_gluon,
CLHEP::HepLorentzVector const & q0,
CLHEP::HepLorentzVector const & pa, CLHEP::HepLorentzVector const & pb,
CLHEP::HepLorentzVector const & p1, CLHEP::HepLorentzVector const & pn,
double lambda
){
double wt = 1;
auto qi = q0;
for(auto gluon_it = begin_gluon; gluon_it != end_gluon; ++gluon_it){
assert(gluon_it->type == pid::gluon);
const auto g = to_HepLorentzVector(*gluon_it);
const auto qip1 = qi - g;
if(treat_as_extremal(*gluon_it)){
wt *= C2Lipatovots(qip1, qi, pa, pb, lambda)*C_A;
} else{
wt *= C2Lipatovots(qip1, qi, pa, pb, p1, pn, lambda)*C_A;
}
qi = qip1;
}
return wt;
}
} // namespace anonymous
std::vector<Particle> MatrixElement::tag_extremal_jet_partons(
Event const & ev
) const{
auto out_partons = filter_partons(ev.outgoing());
if(out_partons.size() == ev.jets().size()){
// no additional emissions in extremal jets, don't need to tag anything
for(auto & parton: out_partons){
parton.p.set_user_index(no_extremal_jet_idx);
}
return out_partons;
}
// TODO: avoid reclustering
fastjet::ClusterSequence cs(to_PseudoJet(out_partons), ev.jet_def());
const auto jets = sorted_by_rapidity(cs.inclusive_jets(ev.min_jet_pt()));
assert(jets.size() >= 2);
auto most_backward = begin(jets);
auto most_forward = end(jets) - 1;
// skip jets caused by unordered emission or qqx
if(ev.type() == event_type::unob || ev.type() == event_type::qqxexb){
assert(jets.size() >= 3);
++most_backward;
}
else if(ev.type() == event_type::unof || ev.type() == event_type::qqxexf){
assert(jets.size() >= 3);
--most_forward;
}
const auto extremal_jet_indices = cs.particle_jet_indices(
{*most_backward, *most_forward}
);
assert(extremal_jet_indices.size() == out_partons.size());
for(size_t i = 0; i < out_partons.size(); ++i){
assert(HEJ::is_parton(out_partons[i]));
const int idx = (extremal_jet_indices[i]>=0)?
extremal_jet_idx:
no_extremal_jet_idx;
out_partons[i].p.set_user_index(idx);
}
return out_partons;
}
double MatrixElement::tree_kin_jets(Event const & ev) const {
auto const & incoming = ev.incoming();
const auto partons = tag_extremal_jet_partons(ev);
if(is_uno(ev.type())){
throw not_implemented("unordered emission not implemented for pure jets");
}
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
const auto p1 = to_HepLorentzVector(partons.front());
const auto pn = to_HepLorentzVector(partons.back());
return ME_current(
incoming[0].type, incoming[1].type,
pn, pb, p1, pa
)/(4.*(N_C*N_C - 1.))*FKL_ladder_weight(
begin(partons) + 1, end(partons) - 1,
pa - p1, pa, pb, p1, pn,
param_.regulator_lambda
);
}
namespace{
double tree_kin_W_FKL(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
auto p1 = to_HepLorentzVector(partons[0]);
auto pn = to_HepLorentzVector(partons[partons.size() - 1]);
const auto begin_ladder = cbegin(partons) + 1;
const auto end_ladder = cend(partons) - 1;
bool wc = aptype==partons[0].type; //leg b emits w
auto q0 = pa - p1;
if(!wc)
q0 -= pl + plbar;
const double current_factor = ME_W_current(
aptype, bptype, pn, pb,
p1, pa, plbar, pl, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder,
q0, pa, pb, p1, pn,
lambda
);
return current_factor*ladder_factor;
}
double tree_kin_W_unob(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
auto pg = to_HepLorentzVector(partons[0]);
auto p1 = to_HepLorentzVector(partons[1]);
auto pn = to_HepLorentzVector(partons[partons.size() - 1]);
const auto begin_ladder = cbegin(partons) + 2;
const auto end_ladder = cend(partons) - 1;
bool wc = aptype==partons[1].type; //leg b emits w
auto q0 = pa - p1 -pg;
if(!wc)
q0 -= pl + plbar;
const double current_factor = ME_W_unob_current(
aptype, bptype, pn, pb,
p1, pa, pg, plbar, pl, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder,
q0, pa, pb, p1, pn,
lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
double tree_kin_W_unof(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
auto p1 = to_HepLorentzVector(partons[0]);
auto pn = to_HepLorentzVector(partons[partons.size() - 2]);
auto pg = to_HepLorentzVector(partons[partons.size() - 1]);
const auto begin_ladder = cbegin(partons) + 1;
const auto end_ladder = cend(partons) - 2;
bool wc = aptype==partons[0].type; //leg b emits w
auto q0 = pa - p1;
if(!wc)
q0 -= pl + plbar;
const double current_factor = ME_W_unof_current(
aptype, bptype, pn, pb,
p1, pa, pg, plbar, pl, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder,
q0, pa, pb, p1, pn,
lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
double tree_kin_W_qqxb(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
HLV pq,pqbar;
if(is_quark(partons[0])){
pq = to_HepLorentzVector(partons[0]);
pqbar = to_HepLorentzVector(partons[1]);
}
else{
pq = to_HepLorentzVector(partons[1]);
pqbar = to_HepLorentzVector(partons[0]);
}
auto p1 = to_HepLorentzVector(partons[0]);
auto pn = to_HepLorentzVector(partons[partons.size() - 1]);
const auto begin_ladder = cbegin(partons) + 2;
const auto end_ladder = cend(partons) - 1;
bool wc = bptype!=partons.back().type; //leg b emits w
auto q0 = pa - pq - pqbar;
if(!wc)
q0 -= pl + plbar;
const double current_factor = ME_W_qqxb_current(
aptype, bptype, pa, pb,
pq, pqbar, pn, plbar, pl, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder,
q0, pa, pb, p1, pn,
lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
double tree_kin_W_qqxf(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
HLV pq,pqbar;
if(is_quark(partons[partons.size() - 1])){
pq = to_HepLorentzVector(partons[partons.size() - 1]);
pqbar = to_HepLorentzVector(partons[partons.size() - 2]);
}
else{
pq = to_HepLorentzVector(partons[partons.size() - 2]);
pqbar = to_HepLorentzVector(partons[partons.size() - 1]);
}
auto p1 = to_HepLorentzVector(partons[0]);
auto pn = to_HepLorentzVector(partons[partons.size() - 1]);
const auto begin_ladder = cbegin(partons) + 1;
const auto end_ladder = cend(partons) - 2;
bool wc = aptype==partons.front().type; //leg b emits w
auto q0 = pa - p1;
if(!wc)
q0 -= pl + plbar;
const double current_factor = ME_W_qqxf_current(
aptype, bptype, pa, pb,
pq, pqbar, p1, plbar, pl, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder,
q0, pa, pb, p1, pn,
lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
double tree_kin_W_qqxmid(
int aptype, int bptype, HLV pa, HLV pb,
std::vector<Particle> const & partons,
HLV plbar, HLV pl,
double lambda
){
HLV pq,pqbar;
const auto backmidquark = std::find_if(
begin(partons)+1, end(partons)-1,
[](Particle const & s){ return s.type != pid::gluon; }
);
assert(backmidquark!=end(partons)-1);
if (is_quark(backmidquark->type)){
pq = to_HepLorentzVector(*backmidquark);
pqbar = to_HepLorentzVector(*(backmidquark+1));
}
else {
pqbar = to_HepLorentzVector(*backmidquark);
pq = to_HepLorentzVector(*(backmidquark+1));
}
auto p1 = to_HepLorentzVector(partons[0]);
auto pn = to_HepLorentzVector(partons[partons.size() - 1]);
auto q0 = pa - p1;
// t-channel momentum after qqx
auto qqxt = q0;
bool wc, wqq;
if (backmidquark->type == -(backmidquark+1)->type){ // Central qqx does not emit
wqq=false;
if (aptype==partons[0].type) {
wc = true;
}
else{
wc = false;
q0-=pl+plbar;
}
}
else{
wqq = true;
wc = false;
qqxt-=pl+plbar;
}
const auto begin_ladder = cbegin(partons) + 1;
const auto end_ladder_1 = (backmidquark);
const auto begin_ladder_2 = (backmidquark+2);
const auto end_ladder = cend(partons) - 1;
for(auto parton_it = begin_ladder; parton_it < begin_ladder_2; ++parton_it){
qqxt -= to_HepLorentzVector(*parton_it);
}
int nabove = std::distance(begin_ladder, backmidquark);
int nbelow = std::distance(begin_ladder_2, end_ladder);
std::vector<HLV> partonsHLV;
partonsHLV.reserve(partons.size());
for (size_t i = 0; i != partons.size(); ++i) {
partonsHLV.push_back(to_HepLorentzVector(partons[i]));
}
const double current_factor = ME_W_qqxmid_current(
aptype, bptype, nabove, nbelow, pa, pb,
pq, pqbar, partonsHLV, plbar, pl, wqq, wc
);
const double ladder_factor = FKL_ladder_weight(
begin_ladder, end_ladder_1,
q0, pa, pb, p1, pn,
lambda
)*FKL_ladder_weight(
begin_ladder_2, end_ladder,
qqxt, pa, pb, p1, pn,
lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
} // namespace anonymous
double MatrixElement::tree_kin_W(Event const & ev) const {
using namespace event_type;
auto const & incoming(ev.incoming());
auto const & decays(ev.decays());
HLV plbar, pl;
for (auto& x: decays) {
if (x.second.at(0).type < 0){
plbar = to_HepLorentzVector(x.second.at(0));
pl = to_HepLorentzVector(x.second.at(1));
}
else{
pl = to_HepLorentzVector(x.second.at(0));
plbar = to_HepLorentzVector(x.second.at(1));
}
}
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
const auto partons = tag_extremal_jet_partons(ev);
if(ev.type() == unordered_backward){
return tree_kin_W_unob(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
if(ev.type() == unordered_forward){
return tree_kin_W_unof(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
if(ev.type() == extremal_qqxb){
return tree_kin_W_qqxb(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
if(ev.type() == extremal_qqxf){
return tree_kin_W_qqxf(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
if(ev.type() == central_qqx){
return tree_kin_W_qqxmid(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
return tree_kin_W_FKL(incoming[0].type, incoming[1].type,
pa, pb, partons, plbar, pl,
param_.regulator_lambda);
}
double MatrixElement::tree_kin_Higgs(Event const & ev) const {
if(is_uno(ev.type())){
return tree_kin_Higgs_between(ev);
}
if(ev.outgoing().front().type == pid::Higgs){
return tree_kin_Higgs_first(ev);
}
if(ev.outgoing().back().type == pid::Higgs){
return tree_kin_Higgs_last(ev);
}
return tree_kin_Higgs_between(ev);
}
namespace {
// Colour acceleration multipliers, for gluons see eq. (7) in arXiv:0910.5113
#ifdef HEJ_BUILD_WITH_QCDLOOP
// TODO: code duplication with jets.cc
double K_g(double p1minus, double paminus) {
return 1./2.*(p1minus/paminus + paminus/p1minus)*(C_A - 1./C_A) + 1./C_A;
}
double K_g(
CLHEP::HepLorentzVector const & pout,
CLHEP::HepLorentzVector const & pin
) {
if(pin.z() > 0) return K_g(pout.plus(), pin.plus());
return K_g(pout.minus(), pin.minus());
}
double K(
ParticleID type,
CLHEP::HepLorentzVector const & pout,
CLHEP::HepLorentzVector const & pin
) {
if(type == ParticleID::gluon) return K_g(pout, pin);
return C_F;
}
#endif
// Colour factor in strict MRK limit
double K_MRK(ParticleID type) {
return (type == ParticleID::gluon)?C_A:C_F;
}
}
double MatrixElement::MH2_forwardH(
CLHEP::HepLorentzVector const & p1out,
CLHEP::HepLorentzVector const & p1in,
ParticleID type2,
CLHEP::HepLorentzVector const & p2out,
CLHEP::HepLorentzVector const & p2in,
CLHEP::HepLorentzVector const & pH,
double t1, double t2
) const{
ignore(p2out, p2in);
const double shat = p1in.invariantMass2(p2in);
// gluon case
#ifdef HEJ_BUILD_WITH_QCDLOOP
if(!param_.Higgs_coupling.use_impact_factors){
return K(type2, p2out, p2in)*C_A*1./(16*M_PI*M_PI)*t1/t2*ME_Houtside_gq(
p1out, p1in, p2out, p2in, pH,
param_.Higgs_coupling.mt, param_.Higgs_coupling.include_bottom,
param_.Higgs_coupling.mb
)/(4*(N_C*N_C - 1));
}
#endif
return K_MRK(type2)/C_A*9./2.*shat*shat*(
C2gHgp(p1in,p1out,pH) + C2gHgm(p1in,p1out,pH)
)/(t1*t2);
}
double MatrixElement::tree_kin_Higgs_first(Event const & ev) const {
auto const & incoming = ev.incoming();
auto const & outgoing = ev.outgoing();
assert(outgoing.front().type == pid::Higgs);
if(outgoing[1].type != pid::gluon) {
assert(incoming.front().type == outgoing[1].type);
return tree_kin_Higgs_between(ev);
}
const auto pH = to_HepLorentzVector(outgoing.front());
const auto partons = tag_extremal_jet_partons(
ev
);
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
const auto p1 = to_HepLorentzVector(partons.front());
const auto pn = to_HepLorentzVector(partons.back());
const auto q0 = pa - p1 - pH;
const double t1 = q0.m2();
const double t2 = (pn - pb).m2();
return MH2_forwardH(
p1, pa, incoming[1].type, pn, pb, pH,
t1, t2
)*FKL_ladder_weight(
begin(partons) + 1, end(partons) - 1,
q0, pa, pb, p1, pn,
param_.regulator_lambda
);
}
double MatrixElement::tree_kin_Higgs_last(Event const & ev) const {
auto const & incoming = ev.incoming();
auto const & outgoing = ev.outgoing();
assert(outgoing.back().type == pid::Higgs);
if(outgoing[outgoing.size()-2].type != pid::gluon) {
assert(incoming.back().type == outgoing[outgoing.size()-2].type);
return tree_kin_Higgs_between(ev);
}
const auto pH = to_HepLorentzVector(outgoing.back());
const auto partons = tag_extremal_jet_partons(
ev
);
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
auto p1 = to_HepLorentzVector(partons.front());
const auto pn = to_HepLorentzVector(partons.back());
auto q0 = pa - p1;
const double t1 = q0.m2();
const double t2 = (pn + pH - pb).m2();
return MH2_forwardH(
pn, pb, incoming[0].type, p1, pa, pH,
t2, t1
)*FKL_ladder_weight(
begin(partons) + 1, end(partons) - 1,
q0, pa, pb, p1, pn,
param_.regulator_lambda
);
}
double MatrixElement::tree_kin_Higgs_between(Event const & ev) const {
using namespace event_type;
auto const & incoming = ev.incoming();
auto const & outgoing = ev.outgoing();
const auto the_Higgs = std::find_if(
begin(outgoing), end(outgoing),
[](Particle const & s){ return s.type == pid::Higgs; }
);
assert(the_Higgs != end(outgoing));
const auto pH = to_HepLorentzVector(*the_Higgs);
const auto partons = tag_extremal_jet_partons(ev);
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
auto p1 = to_HepLorentzVector(
partons[(ev.type() == unob)?1:0]
);
auto pn = to_HepLorentzVector(
partons[partons.size() - ((ev.type() == unof)?2:1)]
);
auto first_after_Higgs = begin(partons) + (the_Higgs-begin(outgoing));
assert(
(first_after_Higgs == end(partons) && (
(ev.type() == unob)
|| partons.back().type != pid::gluon
))
|| first_after_Higgs->rapidity() >= the_Higgs->rapidity()
);
assert(
(first_after_Higgs == begin(partons) && (
(ev.type() == unof)
|| partons.front().type != pid::gluon
))
|| (first_after_Higgs-1)->rapidity() <= the_Higgs->rapidity()
);
// always treat the Higgs as if it were in between the extremal FKL partons
if(first_after_Higgs == begin(partons)) ++first_after_Higgs;
else if(first_after_Higgs == end(partons)) --first_after_Higgs;
// t-channel momentum before Higgs
auto qH = pa;
for(auto parton_it = begin(partons); parton_it != first_after_Higgs; ++parton_it){
qH -= to_HepLorentzVector(*parton_it);
}
auto q0 = pa - p1;
auto begin_ladder = begin(partons) + 1;
auto end_ladder = end(partons) - 1;
double current_factor;
if(ev.type() == unob){
current_factor = C_A*C_A/2.*ME_Higgs_current_unob( // 1/2 = "K_uno"
incoming[0].type, incoming[1].type,
pn, pb, to_HepLorentzVector(partons.front()), p1, pa, qH, qH - pH,
param_.Higgs_coupling.mt,
param_.Higgs_coupling.include_bottom, param_.Higgs_coupling.mb
);
const auto p_unob = to_HepLorentzVector(partons.front());
q0 -= p_unob;
p1 += p_unob;
++begin_ladder;
}
else if(ev.type() == unof){
current_factor = C_A*C_A/2.*ME_Higgs_current_unof( // 1/2 = "K_uno"
incoming[0].type, incoming[1].type,
to_HepLorentzVector(partons.back()), pn, pb, p1, pa, qH, qH - pH,
param_.Higgs_coupling.mt,
param_.Higgs_coupling.include_bottom, param_.Higgs_coupling.mb
);
pn += to_HepLorentzVector(partons.back());
--end_ladder;
}
else{
current_factor = ME_Higgs_current(
incoming[0].type, incoming[1].type,
pn, pb, p1, pa, qH, qH - pH,
param_.Higgs_coupling.mt,
param_.Higgs_coupling.include_bottom, param_.Higgs_coupling.mb
);
}
const double ladder_factor = FKL_ladder_weight(
begin_ladder, first_after_Higgs,
q0, pa, pb, p1, pn,
param_.regulator_lambda
)*FKL_ladder_weight(
first_after_Higgs, end_ladder,
qH - pH, pa, pb, p1, pn,
param_.regulator_lambda
);
return current_factor*C_A*C_A/(N_C*N_C-1.)*ladder_factor;
}
namespace {
double get_AWZH_coupling(Event const & ev, double alpha_s) {
const auto AWZH_boson = std::find_if(
begin(ev.outgoing()), end(ev.outgoing()),
[](auto const & p){return is_AWZH_boson(p);}
);
if(AWZH_boson == end(ev.outgoing())) return 1.;
switch(AWZH_boson->type){
case pid::Higgs:
return alpha_s*alpha_s;
case pid::Wp:
case pid::Wm:
return gw*gw*gw*gw/4.;
// TODO
case pid::photon:
case pid::Z:
default:
throw not_implemented("Emission of boson of unsupported type");
}
}
}
double MatrixElement::tree_param(Event const & ev, double mur) const {
assert(is_resummable(ev.type()));
const auto begin_partons = ev.begin_partons();
const auto end_partons = ev.end_partons();
const auto num_partons = std::distance(begin_partons, end_partons);
const double alpha_s = alpha_s_(mur);
const double gs2 = 4.*M_PI*alpha_s;
double res = std::pow(gs2, num_partons);
if(param_.log_correction){
// use alpha_s(q_perp), evolved to mur
assert(num_partons >= 2);
const auto first_emission = std::next(begin_partons);
const auto last_emission = std::prev(end_partons);
for(auto parton = first_emission; parton != last_emission; ++parton){
res *= 1. + alpha_s/(2.*M_PI)*beta0*log(mur/parton->perp());
}
}
return get_AWZH_coupling(ev, alpha_s)*res;
}
} // namespace HEJ