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diff --git a/include/HEJ/Hjets.hh b/include/HEJ/Hjets.hh
index e7f666d..0a174ef 100644
--- a/include/HEJ/Hjets.hh
+++ b/include/HEJ/Hjets.hh
@@ -1,383 +1,383 @@
/**
* \authors The HEJ collaboration (see AUTHORS for details)
* \date 2019-2020
* \copyright GPLv2 or later
*/
/** \file
* \brief Functions computing the square of current contractions in H+Jets.
*
* This file contains all the H+Jet specific components to compute
* the current contractions for valid HEJ processes, to form a full
* H+Jets ME, currently one would have to use functions from the
* jets.hh header also. We have FKL and also unordered components for
* H+Jets.
*/
#pragma once
#include "CLHEP/Vector/LorentzVector.h"
namespace HEJ {
namespace currents {
using HLV = CLHEP::HepLorentzVector;
//! Square of gg->gg Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state gluon
* @param p1in Momentum of initial state gluon
* @param p2out Momentum of final state gluon
* @param p2in Momentum of intial state gluon
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for gg->gg
*
* g~p1 g~p2
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if g is backward, qH1 is forward)
*/
double ME_H_gg(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
/**
* @brief Square of gq->Hq current contraction
* @param ph Outgoing Higgs boson momentum
* @param pg Incoming gluon momentum
* @param pn Momentum of outgoing particle in FKL current
* @param pb Momentum of incoming particle in FKL current
* @param mt top mass (inf or value)
* @param inc_bottom whether to include bottom mass effects (true) or not (false)
* @param mb bottom mass (value)
* @param vev Higgs vacuum expectation value
*
* Calculates helicity-averaged || \epsilon_\mu V_H^{\mu\nu} j_\nu ||^2.
* See eq:S_gf_Hf in developer manual
*/
double ME_jgH_j(
- HLV const & ph, HLV const & pg,
+ HLV const & ph, HLV const & pa,
HLV const & pn, HLV const & pb,
double mt, bool inc_bottom, double mb, double vev
);
/**
* @brief Square of qg -> gqH current contraction
* @param pg Outgoing (unordered) gluon momentum
* @param ph Outgoing quark momentum
* @param pa Incoming quark momentum
* @param ph Outgoing Higgs boson momentum
* @param pb Incoming gluon momentum
* @param mt top mass (inf or value)
* @param inc_bottom whether to include bottom mass effects (true) or not (false)
* @param mb bottom mass (value)
* @param vev Higgs vacuum expectation value
*
* Calculates helicity-averaged || j_{uno \mu} V_H^{\mu\nu} \epsilon_\nu ||^2.
* See eq:S_gf_Hf in developer manual
*/
double ME_juno_jgH(
HLV const & pg,
HLV const & p1, HLV const & pa,
HLV const & ph, HLV const & pb,
double mt, bool inc_bottom, double mb, double vev
);
//! Square of gq->gq Higgs+Jets Scattering Current with Higgs before Gluon
/**
* @param p1out Momentum of final state gluon
* @param p1in Momentum of initial state gluon
* @param p2out Momentum of final state gluon
* @param p2in Momentum of intial state gluon
* @param pH Momentum of Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contraction
*/
double ME_H_qg(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qbarg->qbarg Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state anti-quark
* @param p1in Momentum of initial state anti-quark
* @param p2out Momentum of final state gluon
* @param p2in Momentum of intial state gluon
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for qbarg->qbarg
*
* qbar~p1 g~p2 (i.e. ALWAYS p1 for anti-quark, p2 for gluon)
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if g is backward, qH1 is forward)
*/
double ME_H_qbarg(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qQ->qQ Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state quark
* @param p1in Momentum of initial state quark
* @param p2out Momentum of final state quark
* @param p2in Momentum of intial state quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for qQ->qQ
*
* q~p1 Q~p2 (i.e. ALWAYS p1 for quark, p2 for quark)
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if Q is backward, qH1 is forward)
*/
double ME_H_qQ(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qQbar->qQbar Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state quark
* @param p1in Momentum of initial state quark
* @param p2out Momentum of final state anti-quark
* @param p2in Momentum of intial state anti-quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for qQ->qQ
*
* q~p1 Qbar~p2 (i.e. ALWAYS p1 for quark, p2 for anti-quark)
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if Qbar is backward, qH1 is forward)
*/
double ME_H_qQbar(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qbarQ->qbarQ Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state anti-quark
* @param p1in Momentum of initial state anti-quark
* @param p2out Momentum of final state quark
* @param p2in Momentum of intial state quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for qbarQ->qbarQ
*
* qbar~p1 Q~p2 (i.e. ALWAYS p1 for anti-quark, p2 for quark)
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if Q is backward, qH1 is forward)
*/
double ME_H_qbarQ(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qbarQbar->qbarQbar Higgs+Jets Scattering Current
/**
* @param p1out Momentum of final state anti-quark
* @param p1in Momentum of initial state anti-quark
* @param p2out Momentum of final state anti-quark
* @param p2in Momentum of intial state anti-quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for
* qbarQbar->qbarQbar
*
* qbar~p1 Qbar~p2 (i.e. ALWAYS p1 for anti-quark, p2 for anti-quark)
* should be called with qH1 meant to be contracted with p2 in first part of
* vertex (i.e. if Qbar is backward, qH1 is forward)
*/
double ME_H_qbarQbar(HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! @name Unordered backwards
//! @{
//! Square of qbarQ->qbarQg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state anti-quark
* @param p1in Momentum of initial state anti-quark
* @param p2out Momentum of final state quark
* @param p2in Momentum of intial state quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for
* qbarQ->qbarQg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_qbarQ(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qQ->qQg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state quark
* @param p1in Momentum of initial state quark
* @param p2out Momentum of final state quark
* @param p2in Momentum of intial state quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for qQ->qQg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_qQ(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qQbar->qQbarg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state quark
* @param p1in Momentum of initial state quark
* @param p2out Momentum of final state anti-quark
* @param p2in Momentum of intial state anti-quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for
* qQbar->qQbarg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_qQbar(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of qbarQbar->qbarQbarg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state anti-quark
* @param p1in Momentum of initial state anti-quark
* @param p2out Momentum of final state anti-quark
* @param p2in Momentum of intial state anti-quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for
* qbarQbar->qbarQbarg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_qbarQbar(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of gQbar->gQbarg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state gluon
* @param p1in Momentum of initial state gluon
* @param p2out Momentum of final state anti-quark
* @param p2in Momentum of intial state anti-quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for
* gQbar->gQbarg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_gQbar(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! Square of gQ->gQg Higgs+Jets Unordered b Scattering Current
/**
* @param pg Momentum of unordered b gluon
* @param p1out Momentum of final state gluon
* @param p1in Momentum of initial state gluon
* @param p2out Momentum of final state quark
* @param p2in Momentum of intial state quark
* @param qH1 Momentum of t-channel propagator before Higgs
* @param qH2 Momentum of t-channel propagator after Higgs
* @param mt Top quark mass
* @param include_bottom Specifies whether bottom corrections are included
* @param mb Bottom quark mass
* @param vev Vacuum expectation value
* @returns Square of the current contractions for gQ->gQg
*
* This construction is taking rapidity order: p1out >> p2out > pg
*/
double ME_H_unob_gQ(HLV const & pg, HLV const & p1out,
HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1,
HLV const & qH2,
double mt,
bool include_bottom, double mb, double vev);
//! @}
} // namespace currents
} // namespace HEJ
diff --git a/src/Hjets.cc b/src/Hjets.cc
index 64a9ecd..5369b21 100644
--- a/src/Hjets.cc
+++ b/src/Hjets.cc
@@ -1,539 +1,537 @@
/**
* \authors The HEJ collaboration (see AUTHORS for details)
* \date 2019-2020
* \copyright GPLv2 or later
*/
#include "HEJ/jets.hh"
#include "HEJ/Hjets.hh"
#include <array>
#include <cassert>
#include <cmath>
#include <complex>
#include <limits>
#include "HEJ/ConfigFlags.hh"
#include "HEJ/Constants.hh"
#include "HEJ/LorentzVector.hh"
#include "HEJ/utility.hh"
// generated headers
#include "HEJ/currents/j_h_j.hh"
#include "HEJ/currents/jgh_j.hh"
#include "HEJ/currents/juno_h_j.hh"
#include "HEJ/currents/juno_jgh.hh"
#ifdef HEJ_BUILD_WITH_QCDLOOP
#include "qcdloop/qcdloop.h"
#else
#include "HEJ/exceptions.hh"
#endif
namespace HEJ {
namespace currents {
namespace {
// short hand for math functions
using std::norm;
- using std::abs;
using std::conj;
- using std::pow;
- using std::sqrt;
constexpr double infinity = std::numeric_limits<double>::infinity(); // NOLINT
// Loop integrals
#ifdef HEJ_BUILD_WITH_QCDLOOP
- const COM LOOPRWFACTOR = (COM(0.,1.)*M_PI*M_PI)/pow((2.*M_PI),4);
+ const COM LOOPRWFACTOR = (COM(0.,1.)*M_PI*M_PI)/std::pow((2.*M_PI),4);
COM B0DD(HLV const & 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 const & q1, HLV const & 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];
}
// Kallen lambda functions, see eq:lambda in developer manual
double lambda(const double s1, const double s2, const double s3) {
return s1*s1 + s2*s2 + s3*s3 - 2*s1*s2 - 2*s1*s3 - 2*s2*s3;
}
// eq: T_1 in developer manual
COM T1(HLV const & q1, HLV const & q2, const double m) {
const double q12 = q1.m2();
const double q22 = q2.m2();
const HLV ph = q1 - q2;
const double ph2 = ph.m2();
const double lam = lambda(q12, q22, ph2);
assert(m > 0.);
const double m2 = m*m;
return
- C0DD(q1, -q2, m)*(2.*m2 + 1./2.*(q12 + q22 - ph2) + 2.*q12*q22*ph2/lam)
- (B0DD(q2, m) - B0DD(ph, m))*(q22 - q12 - ph2)*q22/lam
- (B0DD(q1, m) - B0DD(ph, m))*(q12 - q22 - ph2)*q12/lam
- 1.;
}
// eq: T_2 in developer manual
COM T2(HLV const & q1, HLV const & q2, const double m) {
const double q12 = q1.m2();
const double q22 = q2.m2();
const HLV ph = q1 - q2;
const double ph2 = ph.m2();
const double lam = lambda(q12, q22, ph2);
assert(m > 0.);
const double m2 = m*m;
return
C0DD(q1, -q2, m)*(
4.*m2/lam*(ph2 - q12 - q22) - 1. - 4.*q12*q22/lam*(
1 + 3.*ph2*(q12 + q22 - ph2)/lam
)
)
- (B0DD(q2, m) - B0DD(ph, m))*(1. + 6.*q12/lam*(q22 - q12 + ph2))*2.*q22/lam
- (B0DD(q1, m) - B0DD(ph, m))*(1. + 6.*q22/lam*(q12 - q22 + ph2))*2.*q12/lam
- 2.*(q12 + q22 - ph2)/lam;
}
#else // no QCDloop
COM T1(HLV const & /*q1*/, HLV const & /*q2*/, double /*mt*/){
throw std::logic_error{"T1 called without QCDloop support"};
}
COM T2(HLV const & /*q1*/, HLV const & /*q2*/, double /*mt*/){
throw std::logic_error{"T2 called without QCDloop support"};
}
#endif
// prefactors of g^{\mu \nu} and q_2^\mu q_1^\nu in Higgs boson emission vertex
// see eq:VH in developer manual, but *without* global factor \alpha_s
std::array<COM, 2> TT(
HLV const & qH1, HLV const & qH2,
const double mt, const bool inc_bottom,
const double mb, const double vev
) {
if(mt == infinity) {
std::array<COM, 2> res = {qH1.dot(qH2), 1.};
for(auto & tt: res) tt /= (3.*M_PI*vev);
return res;
}
std::array<COM, 2> res = {T1(qH1, qH2, mt), T2(qH1, qH2, mt)};
for(auto & tt: res) tt *= mt*mt;
if(inc_bottom) {
res[0] += mb*mb*T1(qH1, qH2, mb);
res[1] += mb*mb*T2(qH1, qH2, mb);
}
for(auto & tt: res) tt /= M_PI*vev;
return res;
}
/**
* @brief Higgs+Jets FKL Contributions, function to handle all incoming types.
* @param p1out Outgoing Particle 1
* @param p1in Incoming Particle 1
* @param p2out Outgoing Particle 2
* @param p2in Incoming Particle 2
* @param qH1 t-channel momenta into higgs vertex
* @param qH2 t-channel momenta out of higgs vertex
* @param mt top mass (inf or value)
* @param inc_bottom whether to include bottom mass effects (true) or not (false)
* @param mb bottom mass (value)
* @param vev Higgs vacuum expectation value
*
* 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 const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
const double mt, const bool inc_bottom, const double mb, const double vev
){
using helicity::plus;
using helicity::minus;
const auto qqH1 = split_into_lightlike(qH1);
const HLV qH11 = qqH1.first;
const HLV qH12 = -qqH1.second;
const auto qqH2 = split_into_lightlike(qH2);
const HLV qH21 = qqH2.first;
const HLV qH22 = -qqH2.second;
// since qH1.m2(), qH2.m2() < 0 the following assertions are always true
assert(qH11.e() > 0);
assert(qH12.e() > 0);
assert(qH21.e() > 0);
assert(qH22.e() > 0);
const auto T_pref = TT(qH1, qH2, mt, inc_bottom, mb, vev);
const COM amp_mm = HEJ::j_h_j<minus, minus>(
p1out, p1in, p2out, p2in, qH11, qH12, qH21, qH22, T_pref[0], T_pref[1]
);
const COM amp_mp = HEJ::j_h_j<minus, plus>(
p1out, p1in, p2out, p2in, qH11, qH12, qH21, qH22, T_pref[0], T_pref[1]
);
const COM amp_pm = HEJ::j_h_j<plus, minus>(
p1out, p1in, p2out, p2in, qH11, qH12, qH21, qH22, T_pref[0], T_pref[1]
);
const COM amp_pp = HEJ::j_h_j<plus, plus>(
p1out, p1in, p2out, p2in, qH11, qH12, qH21, qH22, T_pref[0], T_pref[1]
);
static constexpr double num_hel = 4.;
// square of amplitudes, averaged over helicities
const double amp2 = (norm(amp_mm) + norm(amp_mp) + norm(amp_pm) + norm(amp_pp))/num_hel;
return amp2/((p1in-p1out).m2()*(p2in-p2out).m2()*qH1.m2()*qH2.m2());
}
// }
} // namespace
double ME_H_qQ(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2, double mt,
bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_qQbar(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_qbarQ(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_qbarQbar(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_qg(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev)
* K_g(p2out,p2in)/C_A;
}
double ME_H_qbarg(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev)
* K_g(p2out,p2in)/C_A;
}
double ME_H_gg(HLV const & p1out, HLV const & p1in, HLV const & p2out,
HLV const & p2in, HLV const & qH1, HLV const & qH2,
double mt, bool include_bottom, double mb, double vev
){
return j_h_j(p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev)
* K_g(p2out,p2in)/C_A * K_g(p1out,p1in)/C_A;
}
//@}
double ME_jgH_j(
HLV const & ph, HLV const & pa,
HLV const & pn, HLV const & pb,
const double mt, const bool inc_bottom, const double mb, const double vev
){
using helicity::plus;
using helicity::minus;
const auto pH = split_into_lightlike(ph);
const HLV ph1 = pH.first;
const HLV ph2 = pH.second;
// since pH.m2() > 0 the following assertions are always true
assert(ph1.e() > 0);
assert(ph2.e() > 0);
const auto T_pref = TT(pa, pa-ph, mt, inc_bottom, mb, vev);
// only distinguish between same and different helicities,
// the other two combinations just add a factor of 2
const COM amp_mm = HEJ::jgh_j<minus, minus>(
pa, pb, pn, ph1, ph2, T_pref[0], T_pref[1]
);
const COM amp_mp = HEJ::jgh_j<minus, plus>(
pa, pb, pn, ph1, ph2, T_pref[0], T_pref[1]
);
constexpr double hel_factor = 2.;
// sum over squares of helicity amplitudes
return hel_factor*(norm(amp_mm) + norm(amp_mp));
}
namespace {
template<Helicity h1, Helicity h2, Helicity hg>
double amp_juno_jgh(
HLV const & pg, HLV const & p1, HLV const & pa,
HLV const & ph1, HLV const & ph2, HLV const & pb,
std::array<COM, 2> const & T_pref
) {
// TODO: code duplication with Wjets and pure jets
const COM u1 = U1_jgh<h1, h2, hg>(pg, p1, pa, ph1, ph2, pb, T_pref[0], T_pref[1]);
const COM u2 = U2_jgh<h1, h2, hg>(pg, p1, pa, ph1, ph2, pb, T_pref[0], T_pref[1]);
const COM l = L_jgh<h1, h2, hg>(pg, p1, pa, ph1, ph2, pb, T_pref[0], T_pref[1]);
return C_F*std::norm(u1+u2) - C_A*std::real((u1-l)*std::conj(u2+l));
}
- }
+ } // namespace
double ME_juno_jgH(
HLV const & pg,
HLV const & p1, HLV const & pa,
HLV const & ph, HLV const & pb,
const double mt, const bool inc_bottom, const double mb, const double vev
) {
using Helicity::plus;
using Helicity::minus;
const auto T_pref = TT(pb, pb-ph, mt, inc_bottom, mb, vev);
const auto pH = split_into_lightlike(ph);
const HLV ph1 = pH.first;
const HLV ph2 = pH.second;
// since pH.m2() > 0 the following assertions are always true
assert(ph1.e() > 0);
assert(ph2.e() > 0);
// only 4 out of the 8 helicity amplitudes are independent
// we still compute all of them for better numerical stability (mirror check)
MultiArray<double, 2, 2, 2> amp;
+// NOLINTNEXTLINE
#define ASSIGN_HEL(RES, J, H1, H2, HG) \
RES[H1][H2][HG] = J<H1, H2, HG>( \
pg, p1, pa, ph1, ph2, pb, T_pref \
- ) // NOLINT
+ )
ASSIGN_HEL(amp, amp_juno_jgh, minus, minus, minus);
ASSIGN_HEL(amp, amp_juno_jgh, minus, minus, plus);
ASSIGN_HEL(amp, amp_juno_jgh, minus, plus, minus);
ASSIGN_HEL(amp, amp_juno_jgh, minus, plus, plus);
ASSIGN_HEL(amp, amp_juno_jgh, plus, minus, minus);
ASSIGN_HEL(amp, amp_juno_jgh, plus, minus, plus);
ASSIGN_HEL(amp, amp_juno_jgh, plus, plus, minus);
ASSIGN_HEL(amp, amp_juno_jgh, plus, plus, plus);
#undef ASSIGN_HEL
double ampsq = 0.;
for(Helicity h1: {minus, plus}) {
for(Helicity h2: {minus, plus}) {
for(Helicity hg: {minus, plus}) {
ampsq += amp[h1][h2][hg];
}
}
}
return ampsq;
}
namespace {
template<Helicity h1, Helicity h2, Helicity hg>
double amp_juno_h_j(
HLV const & pa, HLV const & pb,
HLV const & pg, HLV const & p1, HLV const & p2,
HLV const & qH11, HLV const & qH12, HLV const & qH21, HLV const & qH22,
std::array<COM, 2> const & T_pref
) {
// TODO: code duplication with Wjets and pure jets
const COM u1 = U1_h_j<h1, h2, hg>(pa,p1,pb,p2,pg,qH11,qH12,qH21,qH22,T_pref[0],T_pref[1]);
const COM u2 = U2_h_j<h1, h2, hg>(pa,p1,pb,p2,pg,qH11,qH12,qH21,qH22,T_pref[0],T_pref[1]);
const COM l = L_h_j<h1, h2, hg>(pa,p1,pb,p2,pg,qH11,qH12,qH21,qH22,T_pref[0],T_pref[1]);
return 2.*C_F*std::real((l-u1)*std::conj(l+u2))
+ 2.*C_F*C_F/3.*std::norm(u1+u2)
;
}
//@{
/**
* @brief Higgs+Jets Unordered Contributions, function to handle all incoming types.
* @param pg Unordered Gluon momenta
* @param p1out Outgoing Particle 1
* @param p1in Incoming Particle 1
* @param p2out Outgoing Particle 2
* @param p2in Incoming Particle 2
* @param qH1 t-channel momenta into higgs vertex
* @param qH2 t-channel momenta out of higgs vertex
* @param mt top mass (inf or value)
* @param inc_bottom whether to include bottom mass effects (true) or not (false)
* @param mb bottom mass (value)
*
* 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 const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in,
HLV const & qH1, HLV const & qH2,
const double mt, const bool incBot, const double mb, const double vev
){
using helicity::plus;
using helicity::minus;
const auto qqH1 = split_into_lightlike(qH1);
const HLV qH11 = qqH1.first;
const HLV qH12 = -qqH1.second;
const auto qqH2 = split_into_lightlike(qH2);
const HLV qH21 = qqH2.first;
const HLV qH22 = -qqH2.second;
// since qH1.m2(), qH2.m2() < 0 the following assertions are always true
assert(qH11.e() > 0);
assert(qH12.e() > 0);
assert(qH21.e() > 0);
assert(qH22.e() > 0);
const auto T_pref = TT(qH1, qH2, mt, incBot, mb, vev);
// only 4 out of the 8 helicity amplitudes are independent
// we still compute all of them for better numerical stability (mirror check)
MultiArray<double, 2, 2, 2> amp{};
// NOLINTNEXTLINE
#define ASSIGN_HEL(RES, J, H1, H2, HG) \
RES[H1][H2][HG] = J<H1, H2, HG>( \
p1in, p2in, pg, p1out, p2out, qH11, qH12, qH21, qH22, T_pref \
)
ASSIGN_HEL(amp, amp_juno_h_j, minus, minus, minus);
ASSIGN_HEL(amp, amp_juno_h_j, minus, minus, plus);
ASSIGN_HEL(amp, amp_juno_h_j, minus, plus, minus);
ASSIGN_HEL(amp, amp_juno_h_j, minus, plus, plus);
ASSIGN_HEL(amp, amp_juno_h_j, plus, minus, minus);
ASSIGN_HEL(amp, amp_juno_h_j, plus, minus, plus);
ASSIGN_HEL(amp, amp_juno_h_j, plus, plus, minus);
ASSIGN_HEL(amp, amp_juno_h_j, plus, plus, plus);
#undef ASSIGN_HEL
const HLV q1 = p1in-p1out; // Top End
const HLV q2 = p2out-p2in; // Bottom End
const HLV qg = p1in-p1out-pg; // Extra bit post-gluon
double ampsq = 0.;
for(Helicity h1: {minus, plus}) {
for(Helicity h2: {minus, plus}) {
for(Helicity hg: {minus, plus}) {
ampsq += amp[h1][h2][hg];
}
}
}
ampsq /= 16.*qg.m2()*qH1.m2()*qH2.m2()*q2.m2();
// Factor of (Cf/Ca) for each quark to match ME_H_qQ.
ampsq*=C_F*C_F/C_A/C_A;
return ampsq;
}
} // namespace
double ME_H_unob_qQ(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_unob_qbarQ(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_unob_qQbar(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_unob_qbarQbar(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev);
}
double ME_H_unob_gQ(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev)
*K_g(p2out,p2in)/C_F;
}
double ME_H_unob_gQbar(HLV const & pg, HLV const & p1out, HLV const & p1in,
HLV const & p2out, HLV const & p2in, HLV const & qH1,
HLV const & qH2, double mt, bool include_bottom, double mb,
double vev
){
return juno_h_j(pg, p1out, p1in, p2out, p2in, qH1, qH2, mt, include_bottom, mb, vev)
*K_g(p2out,p2in)/C_F;
}
//@}
} // namespace currents
} // namespace HEJ
diff --git a/src/PhaseSpacePoint.cc b/src/PhaseSpacePoint.cc
index 4ff0bd1..3f549cb 100644
--- a/src/PhaseSpacePoint.cc
+++ b/src/PhaseSpacePoint.cc
@@ -1,956 +1,955 @@
/**
* \authors The HEJ collaboration (see AUTHORS for details)
* \date 2019-2020
* \copyright GPLv2 or later
*/
#include "HEJ/PhaseSpacePoint.hh"
#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdlib>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <random>
#include <tuple>
#include "fastjet/ClusterSequence.hh"
#include "fastjet/JetDefinition.hh"
#include "HEJ/Constants.hh"
#include "HEJ/Event.hh"
#include "HEJ/JetSplitter.hh"
#include "HEJ/PDG_codes.hh"
#include "HEJ/RNG.hh"
#include "HEJ/event_types.hh"
#include "HEJ/kinematics.hh"
#include "HEJ/resummation_jet.hh"
#include "HEJ/utility.hh"
namespace HEJ {
namespace {
constexpr int MAX_JET_USER_IDX = PhaseSpacePoint::NG_MAX;
bool is_nonjet_parton(fastjet::PseudoJet const & parton){
assert(parton.user_index() != -1);
return parton.user_index() > MAX_JET_USER_IDX;
}
bool is_jet_parton(fastjet::PseudoJet const & parton){
assert(parton.user_index() != -1);
return parton.user_index() <= MAX_JET_USER_IDX;
}
namespace user_idx {
//! user indices for partons with extremal rapidity
enum ID: int {
qqbar_mid1 = -9,
qqbar_mid2 = -8,
qqbarb = -7,
qqbarf = -6,
unob = -5,
unof = -4,
backward_fkl = -3,
forward_fkl = -2,
};
} // namespace user_idx
using UID = user_idx::ID;
double phase_space_normalisation(
int num_Born_jets, int num_out_partons
){
return std::pow(16.*std::pow(M_PI,3), num_Born_jets - num_out_partons);
}
} // namespace
Event::EventData to_EventData(PhaseSpacePoint psp){
Event::EventData result;
result.incoming = std::move(psp).incoming_; // NOLINT(bugprone-use-after-move)
result.outgoing = std::move(psp).outgoing_; // NOLINT(bugprone-use-after-move)
// technically Event::EventData doesn't have to be sorted,
// but PhaseSpacePoint should be anyway
assert(
std::is_sorted(
begin(result.outgoing), end(result.outgoing),
rapidity_less{}
)
);
assert(result.outgoing.size() >= 2);
static_assert(
std::numeric_limits<double>::has_quiet_NaN,
"no quiet NaN for double"
);
constexpr double nan = std::numeric_limits<double>::quiet_NaN();
result.decays = std::move(psp).decays_; // NOLINT(bugprone-use-after-move)
result.parameters.central = {nan, nan, psp.weight()}; // NOLINT(bugprone-use-after-move)
return result;
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::cluster_jets(
std::vector<fastjet::PseudoJet> const & partons
) const{
fastjet::ClusterSequence cs(partons, param_.jet_param.def);
return sorted_by_rapidity(cs.inclusive_jets(param_.jet_param.min_pt));
}
bool PhaseSpacePoint::pass_resummation_cuts(
std::vector<fastjet::PseudoJet> const & jets
) const{
return cluster_jets(jets).size() == jets.size();
}
namespace {
// find iterators to central qqbar emission
auto get_central_qqbar(Event const & ev) {
// find born quarks (ignore extremal partons)
auto const firstquark = std::find_if(
std::next(ev.begin_partons()), std::prev(ev.end_partons(), 2),
[](Particle const & s){ return (is_anyquark(s)); }
);
// assert that it is a q-q_bar pair.
assert(std::distance(firstquark, ev.end_partons()) != 2);
assert(
( is_quark(*firstquark) && is_antiquark(*std::next(firstquark)) )
|| ( is_antiquark(*firstquark) && is_quark(*std::next(firstquark)) )
);
return std::make_pair(firstquark, std::next(firstquark));
}
//! returns index of most backward q-qbar jet
template<class Iterator>
int get_back_quark_jet(Event const & ev, Iterator firstquark){
// find jets at FO corresponding to the quarks
// technically this isn't necessary for LO
std::vector<int> const born_indices{ ev.particle_jet_indices() };
const auto firstquark_idx = std::distance(ev.begin_partons(), firstquark);
int const firstjet_idx = born_indices[firstquark_idx];
assert(firstjet_idx>0);
assert( born_indices[firstquark_idx+1] == firstjet_idx+1 );
return firstjet_idx;
}
//! returns index of most backward q-qbar jet
int getBackQuarkJet(Event const & ev){
const auto firstquark = get_central_qqbar(ev).first;
return get_back_quark_jet(ev, firstquark);
}
} // namespace
double PhaseSpacePoint::estimate_emission_rapidity_range(
Event const & ev
) const {
assert(std::is_sorted(begin(ev.jets()), end(ev.jets()), rapidity_less{}));
const double ymin = is_backward_g_to_h(ev)?
ev.outgoing().front().rapidity():
most_backward_FKL(ev.jets()).rapidity();
const double ymax = is_forward_g_to_h(ev)?
ev.outgoing().back().rapidity():
most_forward_FKL(ev.jets()).rapidity();
double delta_y = ymax - ymin;
// neglect tiny probability for emission between central qqbar pair
if(ev.type() == event_type::central_qqbar) {
const int qjet = getBackQuarkJet(ev);
delta_y -= ev.jets()[qjet+1].rapidity() - ev.jets()[qjet].rapidity();
}
assert(delta_y >= 0);
return delta_y;
}
double PhaseSpacePoint::estimate_ng_mean(Event const & ev) const {
// Formula derived from fit in arXiv:1805.04446 (see Fig. 2)
constexpr double GLUONS_PER_RAPIDITY = 0.975052;
return GLUONS_PER_RAPIDITY*estimate_emission_rapidity_range(ev);
}
int PhaseSpacePoint::sample_ng(Event const & event, RNG & ran){
const double ng_mean = estimate_ng_mean(event);
std::poisson_distribution<int> dist(ng_mean);
const int ng = dist(ran);
assert(ng >= 0);
assert(ng < NG_MAX);
weight_ *= std::tgamma(ng + 1)*std::exp(ng_mean)*std::pow(ng_mean, -ng);
return ng;
}
void PhaseSpacePoint::boost_AWZH_boson_from(
fastjet::PseudoJet const & boosted_boson, Event const & event
){
auto const & from = event.outgoing();
const auto original_boson = std::find_if(
begin(from), end(from),
[](Particle const & p){ return is_AWZH_boson(p); }
);
if(original_boson == end(from)) return;
auto insertion_point = std::lower_bound(
begin(outgoing_), end(outgoing_), *original_boson, rapidity_less{}
);
// copy AWZH particle
outgoing_.insert(insertion_point,
{original_boson->type, boosted_boson, original_boson->colour}
);
assert(std::is_sorted(begin(outgoing_), end(outgoing_), rapidity_less{}));
// copy & boost decay products
const int idx = std::distance(begin(from), original_boson);
assert(idx >= 0);
const auto decay_it = event.decays().find(idx);
if(decay_it == end(event.decays()))
return;
const int new_idx = std::distance(begin(outgoing_), insertion_point);
assert(new_idx >= 0);
assert(outgoing_[new_idx].type == original_boson->type);
auto decayparticles=decay_it->second;
// change the momenta of the decay products.
for(auto & particle: decayparticles){
auto & p = particle.p;
// boost _to_ rest frame of input boson
p.unboost(original_boson->p);
// then boost _from_ rest frame of shuffled boson
p.boost(boosted_boson);
}
decays_.emplace(new_idx, decayparticles);
}
namespace {
template<class ConstIterator, class Iterator>
void label_extremal_qqbar(
ConstIterator born_begin, ConstIterator born_end,
Iterator first_out
){
// find born quarks
const auto firstquark = std::find_if(
born_begin, born_end-1,
[](Particle const & s){ return (is_anyquark(s)); }
);
assert(firstquark != born_end-1);
const auto secondquark = std::find_if(
firstquark+1, born_end,
[](Particle const & s){ return (is_anyquark(s)); }
);
assert(secondquark != born_end);
assert( ( is_quark(*firstquark) && is_antiquark(*secondquark) )
|| ( is_antiquark(*firstquark) && is_quark(*secondquark) ));
assert(first_out->type == ParticleID::gluon);
assert((first_out+1)->type == ParticleID::gluon);
// copy type from born
first_out->type = firstquark->type;
(first_out+1)->type = secondquark->type;
}
} // namespace
void PhaseSpacePoint::label_qqbar(Event const & event){
assert(std::is_sorted(begin(outgoing_), end(outgoing_), rapidity_less{}));
assert(filter_partons(outgoing_).size() == outgoing_.size());
if(qqbarb_){
label_extremal_qqbar(event.outgoing().cbegin(), event.outgoing().cend(),
outgoing_.begin() );
return;
}
if(qqbarf_){ // same as qqbarb with reversed order
label_extremal_qqbar( event.outgoing().crbegin(), event.outgoing().crend(),
outgoing_.rbegin() );
return;
}
// central qqbar
const auto firstquark = get_central_qqbar(event).first;
// find jets at FO corresponding to the quarks
// technically this isn't necessary for LO
const auto firstjet_idx = get_back_quark_jet(event, firstquark);
// find corresponding jets after resummation
fastjet::ClusterSequence cs{to_PseudoJet(outgoing_), param_.jet_param.def};
auto const jets = fastjet::sorted_by_rapidity(
cs.inclusive_jets( param_.jet_param.min_pt ));
std::vector<int> const resum_indices{ cs.particle_jet_indices({jets}) };
// assert that jets didn't move
assert(nearby_ep( ( event.jets().cbegin()+firstjet_idx )->rapidity(),
jets[ firstjet_idx ].rapidity(), 1e-2) );
assert(nearby_ep( ( event.jets().cbegin()+firstjet_idx+1 )->rapidity(),
jets[ firstjet_idx+1 ].rapidity(), 1e-2) );
// find last partons in first (central) jet
size_t idx_out = 0;
for(size_t i=resum_indices.size()-2; i>0; --i)
if(resum_indices[i] == firstjet_idx){
idx_out = i;
break;
}
assert(idx_out != 0);
// check that there is sufficient pt in jets from the quarks
const double minpartonjetpt = 1. - param_.soft_pt_regulator;
if (outgoing_[idx_out].p.pt()<minpartonjetpt*( event.jets().cbegin()+firstjet_idx )->pt()){
weight_=0.;
status_ = StatusCode::wrong_jets;
return;
}
if (outgoing_[idx_out+1].p.pt()<minpartonjetpt*( event.jets().cbegin()+firstjet_idx+1 )->pt()){
weight_=0.;
status_ = StatusCode::wrong_jets;
return;
}
// check that no additional emission between jets
// such configurations are possible if we have an gluon gets generated
// inside the rapidities of the qqbar chain, but clusted to a
// differnet/outside jet. Changing this is non trivial
if(resum_indices[idx_out+1] != resum_indices[idx_out]+1){
weight_=0.;
status_ = StatusCode::gluon_in_qqbar;
return;
}
outgoing_[idx_out].type = firstquark->type;
outgoing_[idx_out+1].type = std::next(firstquark)->type;
}
void PhaseSpacePoint::label_quarks(Event const & ev){
const auto WZEmit = std::find_if(
begin(ev.outgoing()), end(ev.outgoing()),
[](Particle const & s){ return (std::abs(s.type) == pid::Wp || s.type == pid::Z_photon_mix); }
);
if (WZEmit != end(ev.outgoing())){
if(!qqbarb_) {
const size_t backward_FKL_idx = unob_?1:0;
const auto backward_FKL = std::next(ev.begin_partons(), backward_FKL_idx);
outgoing_[backward_FKL_idx].type = backward_FKL->type;
}
if(!qqbarf_) {
const size_t forward_FKL_idx = unof_?1:0;
const auto forward_FKL = std::prev(ev.end_partons(), 1+forward_FKL_idx);
outgoing_.rbegin()[unof_].type = forward_FKL->type; // NOLINT
}
} else {
if(!is_backward_g_to_h(ev)) {
most_backward_FKL(outgoing_).type = ev.incoming().front().type;
}
if(!is_forward_g_to_h(ev)) {
most_forward_FKL(outgoing_).type = ev.incoming().back().type;
}
}
if(qqbar_mid_||qqbarb_||qqbarf_){
label_qqbar(ev);
}
}
PhaseSpacePoint::PhaseSpacePoint(
Event const & ev, PhaseSpacePointConfig conf, RNG & ran
):
unob_{ev.type() == event_type::unob},
unof_{ev.type() == event_type::unof},
qqbarb_{ev.type() == event_type::qqbar_exb},
qqbarf_{ev.type() == event_type::qqbar_exf},
qqbar_mid_{ev.type() == event_type::qqbar_mid},
param_{std::move(conf)},
status_{unspecified}
{
// legacy code: override new variable with old
if(param_.max_ext_soft_pt_fraction){
param_.soft_pt_regulator = *param_.max_ext_soft_pt_fraction;
param_.max_ext_soft_pt_fraction = {};
}
weight_ = 1;
auto const & Born_jets = ev.jets();
const int ng = sample_ng(ev, ran);
weight_ /= std::tgamma(ng + 1);
const int ng_jets = sample_ng_jets(ev, ng, ran);
std::vector<fastjet::PseudoJet> out_partons = gen_non_jet(
ng - ng_jets, CMINPT, param_.jet_param.min_pt, ran
);
const auto qperp = std::accumulate(
begin(out_partons), end(out_partons),
fastjet::PseudoJet{}
);
std::vector<fastjet::PseudoJet> jets;
optional<fastjet::PseudoJet> boson;
std::tie(jets, boson) = reshuffle(ev, qperp);
if(weight_ == 0.) {
status_ = failed_reshuffle;
return;
}
if(! pass_resummation_cuts(jets)){
status_ = failed_resummation_cuts;
weight_ = 0.;
return;
}
// split jets in multiple partons
std::vector<fastjet::PseudoJet> jet_partons = split(
ev, jets, ng_jets, ran
);
if(weight_ == 0.) {
status_ = StatusCode::failed_split;
return;
}
const double ymin = is_backward_g_to_h(ev)?
ev.outgoing().front().rapidity():
most_backward_FKL(jet_partons).rapidity()
;
const double ymax = is_forward_g_to_h(ev)?
ev.outgoing().back().rapidity():
most_forward_FKL(jet_partons).rapidity()
;
if(qqbar_mid_){
const int qqbar_backjet = getBackQuarkJet(ev);
rescale_qqbar_rapidities(
out_partons, jets,
ymin, ymax,
qqbar_backjet
);
}
else{
rescale_rapidities(out_partons, ymin, ymax);
}
if(! cluster_jets(out_partons).empty()){
weight_ = 0.;
status_ = StatusCode::empty_jets;
return;
}
std::sort(begin(out_partons), end(out_partons), rapidity_less{});
assert(
std::is_sorted(begin(jet_partons), end(jet_partons), rapidity_less{})
);
const auto first_jet_parton = out_partons.insert(
end(out_partons), begin(jet_partons), end(jet_partons)
);
std::inplace_merge(
begin(out_partons), first_jet_parton, end(out_partons), rapidity_less{}
);
if(! jets_ok(ev, out_partons)){
weight_ = 0.;
status_ = StatusCode::wrong_jets;
return;
}
weight_ *= phase_space_normalisation(Born_jets.size(), out_partons.size());
outgoing_.reserve(out_partons.size() + 1); // one slot for possible A, W, Z, H
for( auto it = std::make_move_iterator(out_partons.begin());
it != std::make_move_iterator(out_partons.end());
++it
){
outgoing_.emplace_back( Particle{pid::gluon, *it, {}});
}
assert(!outgoing_.empty());
label_quarks(ev);
if(weight_ == 0.) {
//! @TODO optimise s.t. this is not possible
// status is handled internally
return;
}
// reattach boson & decays
if(boson){
boost_AWZH_boson_from(*boson, ev);
}
reconstruct_incoming(ev.incoming());
status_ = StatusCode::good;
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::gen_non_jet(
int const ng_non_jet, double const ptmin, double const ptmax, RNG & ran
){
// heuristic parameters for pt sampling
const double ptpar = 1.3 + ng_non_jet/5.;
const double temp1 = std::atan((ptmax - ptmin)/ptpar);
std::vector<fastjet::PseudoJet> partons(ng_non_jet);
for(int i = 0; i < ng_non_jet; ++i){
const double r1 = ran.flat();
const double pt = ptmin + ptpar*std::tan(r1*temp1);
const double temp2 = std::cos(r1*temp1);
const double phi = 2*M_PI*ran.flat();
weight_ *= 2.0*M_PI*pt*ptpar*temp1/(temp2*temp2);
// we don't know the allowed rapidity span yet,
// set a random value to be rescaled later on
const double y = ran.flat();
partons[i].reset_PtYPhiM(pt, y, phi);
// Set user index higher than any jet-parton index
// in order to assert that these are not inside jets
partons[i].set_user_index(i + 1 + NG_MAX);
assert(ptmin-1e-5 <= partons[i].pt() && partons[i].pt() <= ptmax+1e-5);
}
assert(std::all_of(partons.cbegin(), partons.cend(), is_nonjet_parton));
return sorted_by_rapidity(partons);
}
void PhaseSpacePoint::rescale_qqbar_rapidities(
std::vector<fastjet::PseudoJet> & out_partons,
std::vector<fastjet::PseudoJet> const & jets,
const double ymin1, const double ymax2,
const int qqbar_backjet
){
const double ymax1 = jets[qqbar_backjet].rapidity();
const double ymin2 = jets[qqbar_backjet+1].rapidity();
constexpr double ep = 1e-7;
const double tot_y = ymax1 - ymin1 + ymax2 - ymin2;
std::vector<std::reference_wrapper<fastjet::PseudoJet>> refpart(
out_partons.begin(), out_partons.end());
double ratio = (ymax1 - ymin1)/tot_y;
const auto gap{ std::find_if(refpart.begin(), refpart.end(),
[ratio](fastjet::PseudoJet const & p){
return (p.rapidity()>=ratio);} ) };
double ymin = ymin1;
double ymax = ymax1;
double dy = ymax - ymin - 2*ep;
double offset = 0.;
for(auto it_part=refpart.begin(); it_part<refpart.end(); ++it_part){
if(it_part == gap){
ymin = ymin2;
ymax = ymax2;
dy = ymax - ymin - 2*ep;
offset = ratio;
ratio = 1-ratio;
}
fastjet::PseudoJet & part = *it_part;
assert(offset <= part.rapidity() && part.rapidity() < ratio+offset);
const double y = ymin + ep + dy*((part.rapidity()-offset)/ratio);
part.reset_momentum_PtYPhiM(part.pt(), y, part.phi());
weight_ *= tot_y-4.*ep;
assert(ymin <= part.rapidity() && part.rapidity() <= ymax);
}
assert(is_sorted(begin(out_partons), end(out_partons), rapidity_less{}));
}
void PhaseSpacePoint::rescale_rapidities(
std::vector<fastjet::PseudoJet> & partons,
double ymin, double ymax
){
constexpr double ep = 1e-7;
for(auto & parton: partons){
assert(0 <= parton.rapidity() && parton.rapidity() <= 1);
const double dy = ymax - ymin - 2*ep;
const double y = ymin + ep + dy*parton.rapidity();
parton.reset_momentum_PtYPhiM(parton.pt(), y, parton.phi());
weight_ *= dy;
assert(ymin <= parton.rapidity() && parton.rapidity() <= ymax);
}
}
namespace {
template<typename T, typename... Rest>
auto min(T const & a, T const & b, Rest&&... r) {
using std::min;
return min(a, min(b, std::forward<Rest>(r)...));
}
}
double PhaseSpacePoint::probability_in_jet(Event const & ev) const{
const double dy = estimate_emission_rapidity_range(ev);
const double R = param_.jet_param.def.R();
// jets into which we predominantly emit
const int njets = ev.jets().size() - unof_ - unob_ - qqbarb_ - qqbarf_; //NOLINT
assert(njets >= 1);
const size_t nextremal_jets = std::min(njets, 2);
const double p_J_y_large = (njets - nextremal_jets/2.)*R*R/(2.*dy);
const double p_J_y0 = njets*R/M_PI;
return min(p_J_y_large, p_J_y0, 1.);
}
int PhaseSpacePoint::sample_ng_jets(Event const & event, int ng, RNG & ran){
const double p_J = probability_in_jet(event);
std::binomial_distribution<> bin_dist(ng, p_J);
const int ng_J = bin_dist(ran);
weight_ *= std::pow(p_J, -ng_J)*std::pow(1 - p_J, ng_J - ng);
return ng_J;
}
std::pair< std::vector<fastjet::PseudoJet>,
optional<fastjet::PseudoJet> >
PhaseSpacePoint::reshuffle(
Event const & ev,
fastjet::PseudoJet const & q
){
// Create a copy of the outgoing momenta not containing decay products
std::vector<fastjet::PseudoJet const *> born_momenta;
born_momenta.reserve(ev.jets().size());
std::transform(ev.jets().cbegin(), ev.jets().cend(),
back_inserter(born_momenta),
[](fastjet::PseudoJet const & t) { return &t; });
// check if there is one (or more) bosons in the event.
const auto AWZH_boson = std::find_if(
begin(ev.outgoing()), end(ev.outgoing()),
[](Particle const & p){ return is_AWZH_boson(p); }
);
optional<fastjet::PseudoJet> boson;
if(AWZH_boson != end(ev.outgoing())){
boson = AWZH_boson->p;
}
// reshuffle all momenta
if(q == fastjet::PseudoJet{0, 0, 0, 0}) return {ev.jets(), boson};
// add boson to reshuffling
if(boson) {
born_momenta.push_back(&*boson);
}
auto shuffle_momenta = resummation_jet_momenta(born_momenta, q);
if(shuffle_momenta.empty()){
weight_ = 0;
return {};
}
// additional Jacobian to ensure Born integration over delta gives 1
weight_ *= resummation_jet_weight(born_momenta, q);
// take out boson again
optional<fastjet::PseudoJet> shuffle_boson;
if(boson){
shuffle_boson = std::move(shuffle_momenta.back());
shuffle_momenta.pop_back();
}
return {shuffle_momenta, shuffle_boson};
}
std::vector<int> PhaseSpacePoint::distribute_jet_partons(
int ng_jets, std::vector<fastjet::PseudoJet> const & jets, RNG & ran
){
size_t first_valid_jet = 0;
size_t num_valid_jets = jets.size();
const double R_eff = 5./3.*param_.jet_param.def.R();
// if there is an unordered jet too far away from the FKL jets
// then extra gluon constituents of the unordered jet would
// violate the FKL rapidity ordering
if((unob_||qqbarb_) && jets[0].delta_R(jets[1]) > R_eff){
++first_valid_jet;
--num_valid_jets;
}
else if((unof_||qqbarf_) && jets[jets.size()-1].delta_R(jets[jets.size()-2]) > R_eff){
--num_valid_jets;
}
std::vector<int> np(jets.size(), 1);
for(int i = 0; i < ng_jets; ++i){
++np[first_valid_jet + ran.flat() * num_valid_jets];
}
weight_ *= std::pow(num_valid_jets, ng_jets);
return np;
}
#ifndef NDEBUG
namespace {
bool tagged_FKL_backward(
std::vector<fastjet::PseudoJet> const & jet_partons
){
return std::find_if(
begin(jet_partons), end(jet_partons),
[](fastjet::PseudoJet const & p){
return p.user_index() == UID::backward_fkl;
}
) != end(jet_partons);
}
bool tagged_FKL_forward(
std::vector<fastjet::PseudoJet> const & jet_partons
){
// the most forward FKL parton is most likely near the end of jet_partons;
// start search from there
return std::find_if(
jet_partons.rbegin(), jet_partons.rend(),
[](fastjet::PseudoJet const & p){
return p.user_index() == UID::forward_fkl;
}
) != jet_partons.rend();
}
} // namespace
#endif
std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
Event const & Born_event,
std::vector<fastjet::PseudoJet> const & jets,
int ng_jets
, RNG & ran
){
return split(
Born_event,
jets,
distribute_jet_partons(ng_jets, jets, ran),
ran
);
}
bool PhaseSpacePoint::pass_extremal_cuts(
fastjet::PseudoJet const & ext_parton,
fastjet::PseudoJet const & jet
) const{
if(ext_parton.pt() < param_.min_extparton_pt) return false;
return (ext_parton - jet).pt()/jet.pt() < param_.soft_pt_regulator;
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
Event const & Born_event,
std::vector<fastjet::PseudoJet> const & jets,
std::vector<int> const & np,
RNG & ran
){
assert(! jets.empty());
assert(jets.size() == np.size());
assert(pass_resummation_cuts(jets));
constexpr auto no_such_jet_idx = std::numeric_limits<std::size_t>::max();
const size_t most_backward_FKL_idx = is_backward_g_to_h(Born_event)?
no_such_jet_idx: // we have backward Higgs instead of FKL jet
(0 + unob_ + qqbarb_); // NOLINT
const size_t most_forward_FKL_idx = is_forward_g_to_h(Born_event)?
no_such_jet_idx: // we have forward Higgs instead of FKL jet
(jets.size() - 1 - unof_ - qqbarf_); // NOLINT
const size_t qqbar_jet_idx = qqbar_mid_?
getBackQuarkJet(Born_event):
no_such_jet_idx;
auto const & jet = param_.jet_param;
const JetSplitter jet_splitter{jet.def, jet.min_pt};
std::vector<fastjet::PseudoJet> jet_partons;
// randomly distribute jet gluons among jets
for(size_t i = 0; i < jets.size(); ++i){
auto split_res = jet_splitter.split(jets[i], np[i], ran);
weight_ *= split_res.weight;
if(weight_ == 0) return {};
assert(
std::all_of(
begin(split_res.constituents), end(split_res.constituents),
is_jet_parton
)
);
const auto first_new_parton = jet_partons.insert(
end(jet_partons),
begin(split_res.constituents), end(split_res.constituents)
);
// mark uno and extremal FKL emissions here so we can check
// their position once all emissions are generated
// also mark qqbar_mid partons, and apply appropriate pt cut.
auto extremal = end(jet_partons);
if (i == most_backward_FKL_idx){ //FKL backward emission
extremal = std::min_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(UID::backward_fkl);
}
else if(((unob_ || qqbarb_) && i == 0)){
// unordered/qqbarb
extremal = std::min_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index((unob_)?UID::unob:UID::qqbarb);
}
else if (i == most_forward_FKL_idx){
extremal = std::max_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(UID::forward_fkl);
}
else if(((unof_ || qqbarf_) && i == jets.size() - 1)){
// unordered/qqbarf
extremal = std::max_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index((unof_)?UID::unof:UID::qqbarf);
}
else if((qqbar_mid_ && i == qqbar_jet_idx)){
extremal = std::max_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(UID::qqbar_mid1);
}
else if((qqbar_mid_ && i == qqbar_jet_idx+1)){
extremal = std::min_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(UID::qqbar_mid2);
}
if(
extremal != end(jet_partons)
&& !pass_extremal_cuts(*extremal, jets[i])
){
weight_ = 0;
return {};
}
}
assert(is_backward_g_to_h(Born_event) || tagged_FKL_backward(jet_partons));
assert(is_forward_g_to_h(Born_event) || tagged_FKL_forward(jet_partons));
std::sort(begin(jet_partons), end(jet_partons), rapidity_less{});
if(
!extremal_ok(Born_event, jet_partons)
|| !split_preserved_jets(jets, jet_partons)
){
weight_ = 0.;
return {};
}
return jet_partons;
}
bool PhaseSpacePoint::extremal_ok(
Event const & Born_event,
std::vector<fastjet::PseudoJet> const & partons
) const{
assert(std::is_sorted(begin(partons), end(partons), rapidity_less{}));
if(unob_ && partons.front().user_index() != UID::unob) return false;
if(unof_ && partons.back().user_index() != UID::unof) return false;
if(qqbarb_ && partons.front().user_index() != UID::qqbarb) return false;
if(qqbarf_ && partons.back().user_index() != UID::qqbarf) return false;
if(is_backward_g_to_h(Born_event)) {
if(partons.front().rapidity() < Born_event.outgoing().front().rapidity()){
return false;
}
} else if(most_backward_FKL(partons).user_index() != UID::backward_fkl) {
return false;
}
if(is_forward_g_to_h(Born_event)) {
return partons.back().rapidity() <= Born_event.outgoing().back().rapidity();
- } else {
- return most_forward_FKL(partons).user_index() == UID::forward_fkl;
}
+ return most_forward_FKL(partons).user_index() == UID::forward_fkl;
}
bool PhaseSpacePoint::split_preserved_jets(
std::vector<fastjet::PseudoJet> const & jets,
std::vector<fastjet::PseudoJet> const & jet_partons
) const{
assert(std::is_sorted(begin(jets), end(jets), rapidity_less{}));
const auto split_jets = cluster_jets(jet_partons);
// this can happen if two overlapping jets
// are both split into more than one parton
if(split_jets.size() != jets.size()) return false;
for(size_t i = 0; i < split_jets.size(); ++i){
// this can happen if there are two overlapping jets
// and a parton is assigned to the "wrong" jet
if(!nearby_ep(jets[i].rapidity(), split_jets[i].rapidity(), 1e-2)){
return false;
}
}
return true;
}
template<class Particle>
Particle const & PhaseSpacePoint::most_backward_FKL(
std::vector<Particle> const & partons
) const{
return partons[0 + unob_ + qqbarb_];
}
template<class Particle>
Particle const & PhaseSpacePoint::most_forward_FKL(
std::vector<Particle> const & partons
) const{
const size_t idx = partons.size() - 1 - unof_ - qqbarf_;
assert(idx < partons.size());
return partons[idx];
}
template<class Particle>
Particle & PhaseSpacePoint::most_backward_FKL(
std::vector<Particle> & partons
) const{
return partons[0 + unob_ + qqbarb_];
}
template<class Particle>
Particle & PhaseSpacePoint::most_forward_FKL(
std::vector<Particle> & partons
) const{
const size_t idx = partons.size() - 1 - unof_ - qqbarf_;
assert(idx < partons.size());
return partons[idx];
}
bool PhaseSpacePoint::contains_idx(
fastjet::PseudoJet const & jet, fastjet::PseudoJet const & parton
) const {
auto const & constituents = jet.constituents();
const int idx = parton.user_index();
const bool injet = std::find_if(
begin(constituents), end(constituents),
[idx](fastjet::PseudoJet const & con){return con.user_index() == idx;}
) != end(constituents);
const double minpartonjetpt = 1. - param_.soft_pt_regulator;
return ((parton.pt()>minpartonjetpt*jet.pt())&&injet);
}
bool PhaseSpacePoint::jets_ok(
Event const & Born_event,
std::vector<fastjet::PseudoJet> const & partons
) const{
fastjet::ClusterSequence cs(partons, param_.jet_param.def);
const auto jets = sorted_by_rapidity(cs.inclusive_jets(param_.jet_param.min_pt));
if(jets.size() != Born_event.jets().size()) return false;
int in_jet = 0;
for(auto const & jet : jets){
assert(jet.has_constituents());
for(auto && parton: jet.constituents()){
if(is_nonjet_parton(parton)) return false;
}
in_jet += jet.constituents().size();
}
const int expect_in_jet = std::count_if(
partons.cbegin(), partons.cend(), is_jet_parton
);
if(in_jet != expect_in_jet) return false;
// note that PseudoJet::contains does not work here
if(
!is_backward_g_to_h(Born_event) &&
!contains_idx(most_backward_FKL(jets), most_backward_FKL(partons))
) return false;
if(
!is_forward_g_to_h(Born_event)
&& !contains_idx(most_forward_FKL(jets), most_forward_FKL(partons))
) return false;
if(unob_ && !contains_idx(jets.front(), partons.front())) return false;
if(qqbarb_ && !contains_idx(jets.front(), partons.front())) return false;
if(unof_ && !contains_idx(jets.back(), partons.back())) return false;
if(qqbarf_ && !contains_idx(jets.back(), partons.back())) return false;
#ifndef NDEBUG
for(size_t i = 0; i < jets.size(); ++i){
assert(nearby_ep(jets[i].rapidity(), Born_event.jets()[i].rapidity(), 1e-2));
}
#endif
return true;
}
void PhaseSpacePoint::reconstruct_incoming(
std::array<Particle, 2> const & Born_incoming
){
std::tie(incoming_[0].p, incoming_[1].p) = incoming_momenta(outgoing_);
for(size_t i = 0; i < incoming_.size(); ++i){
incoming_[i].type = Born_incoming[i].type;
}
assert(momentum_conserved());
}
bool PhaseSpacePoint::momentum_conserved() const{
fastjet::PseudoJet diff;
for(auto const & in: incoming()) diff += in.p;
const double norm = diff.E();
for(auto const & out: outgoing()) diff -= out.p;
return nearby(diff, fastjet::PseudoJet{}, norm);
}
} //namespace HEJ

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