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diff --git a/include/RHEJ/Constants.hh b/include/RHEJ/Constants.hh
new file mode 100644
index 0000000..5960484
--- /dev/null
+++ b/include/RHEJ/Constants.hh
@@ -0,0 +1,21 @@
+/** \file Constants.hh
+ * \brief Header file defining all global constants used for HEJ
+ */
+#pragma once
+
+namespace RHEJ{
+/// @name QCD parameters
+//@{
+ constexpr int N_C = 3; //!< number of Colors
+ constexpr int C_A = N_C; //!< \f$C_A\f$
+ constexpr double C_F = (N_C*N_C - 1.)/(2.*N_C); //!< \f$C_F\f$
+ constexpr double t_f = 0.5; //!< \f$t_f\f$
+ constexpr int n_f = 5; //!< number light flavors
+ constexpr double beta0 = 11./3.*C_A - 4./3.*t_f*n_f; //!< \f$\beta_0\f$
+//@}
+/// @name Generation Parameters
+//@{
+ constexpr double CLAMBDA = 0.2; //!< Scale for virtual correction, \f$\lambda\f$ cf. eq. (20) in \cite Andersen:2011hs
+ constexpr double CMINPT = CLAMBDA; //!< minimal \f$p_t\f$ of all partons
+//@}
+}
diff --git a/include/RHEJ/PhaseSpacePoint.hh b/include/RHEJ/PhaseSpacePoint.hh
index 906fe9c..4d32587 100644
--- a/include/RHEJ/PhaseSpacePoint.hh
+++ b/include/RHEJ/PhaseSpacePoint.hh
@@ -1,162 +1,157 @@
/** \file PhaseSpacePoint.hh
* \brief Contains the PhaseSpacePoint Class
*/
#pragma once
#include <vector>
#include <CLHEP/Random/Randomize.h>
#include <CLHEP/Random/RanluxEngine.h>
#include "RHEJ/utility.hh"
#include "RHEJ/config.hh"
#include "RHEJ/Event.hh"
#include "RHEJ/Splitter.hh"
namespace RHEJ{
//! A point in resummation phase space
class PhaseSpacePoint{
public:
//! Default PhaseSpacePoint Constructor
PhaseSpacePoint() = default;
//! PhaseSpacePoint Constructor
/**
* @param ev Clustered Jet Event
* @param conf Configuration parameters
*/
PhaseSpacePoint(
Event const & ev,
Config const & conf
);
//! Get Weight Function
/**
* @returns Weight of Event
*/
double weight() const{
return weight_;
}
//! Get Incoming Function
/**
* @returns Incoming Particles
*/
std::array<Sparticle, 2> const & incoming() const{
return incoming_;
}
//! Get Outgoing Function
/**
* @returns Outgoing Particles
*/
std::vector<Sparticle> const & outgoing() const{
return outgoing_;
}
std::unordered_map<int, std::vector<Sparticle>> const & decays() const{
return decays_;
}
- static constexpr double ccut = 0.2; // universal min pt cut
static constexpr int ng_max = 1000; // maximum number of extra gluons
static void reset_ranlux(std::string const & init_file);
static void reset_ranlux(char const * init_file);
private:
std::vector<fastjet::PseudoJet> cluster_jets(
std::vector<fastjet::PseudoJet> const & partons
) const;
bool pass_resummation_cuts(
std::vector<fastjet::PseudoJet> const & jets
) const;
bool pass_extremal_cuts(
fastjet::PseudoJet const & ext_parton,
fastjet::PseudoJet const & jet
) const;
int sample_ng(std::vector<fastjet::PseudoJet> const & Born_jets);
int sample_ng_jets(int ng, std::vector<fastjet::PseudoJet> const & Born_jets);
double probability_in_jet(
std::vector<fastjet::PseudoJet> const & Born_jets
) const;
std::vector<fastjet::PseudoJet> gen_non_jet(
int ng_non_jet,
double ptmin, double ptmax
);
void rescale_rapidities(
std::vector<fastjet::PseudoJet> & partons,
double ymin, double ymax
);
std::vector<fastjet::PseudoJet> reshuffle(
std::vector<fastjet::PseudoJet> const & Born_jets,
fastjet::PseudoJet const & q
);
bool jets_ok(
std::vector<fastjet::PseudoJet> const & Born_jets,
std::vector<fastjet::PseudoJet> const & partons
) const;
void reconstruct_incoming(std::array<Sparticle, 2> const & Born_incoming);
double phase_space_normalisation(
int num_Born_jets,
int num_res_partons
) const;
std::vector<fastjet::PseudoJet> split(
std::vector<fastjet::PseudoJet> const & jets, int ng_jets
);
std::vector<int> distribute_jet_partons(
int ng_jets, std::vector<fastjet::PseudoJet> const & jets
);
std::vector<fastjet::PseudoJet> split(
std::vector<fastjet::PseudoJet> const & jets,
std::vector<int> const & np_in_jet
);
bool split_preserved_jets(
std::vector<fastjet::PseudoJet> const & jets,
std::vector<fastjet::PseudoJet> const & jet_partons
) const;
template<class Particle>
Particle const & most_backward_FKL(
std::vector<Particle> const & partons
) const;
template<class Particle>
Particle const & most_forward_FKL(
std::vector<Particle> const & partons
) const;
template<class Particle>
Particle & most_backward_FKL(std::vector<Particle> & partons) const;
template<class Particle>
Particle & most_forward_FKL(std::vector<Particle> & partons) const;
bool extremal_ok(
std::vector<fastjet::PseudoJet> const & partons
) const;
void copy_AWZH_boson_from(Event const & event);
bool momentum_conserved(double ep) const;
bool unob_, unof_;
double weight_;
- // double extpartonptmin_;
- // double max_ext_soft_pt_fraction_;
- // double jetptmin_;
- // fastjet::JetDefinition jet_def_;
const PhaseSpacePointParameters param;
std::array<Sparticle, 2> incoming_;
std::vector<Sparticle> outgoing_;
//! Particle decays in the format {outgoing index, decay products}
std::unordered_map<int, std::vector<Sparticle>> decays_;
static CLHEP::Ranlux64Engine ran_;
HejSplit splitter_;
};
}
diff --git a/include/RHEJ/config.hh b/include/RHEJ/config.hh
index 0e154f6..6b36c92 100644
--- a/include/RHEJ/config.hh
+++ b/include/RHEJ/config.hh
@@ -1,197 +1,194 @@
/** \file config.hh
* \brief The file which handles the configuration file parameters
*
* Contains the JetParameters Struct and ScaleConfig Struct. Also
* contains the ScaleGenerator Class and the EventTreatment class.
* Config struct is also defined here. The configuration files
* parameters are read and then stored within this objects.
*/
#pragma once
#include <string>
#include <memory>
#include "fastjet/JetDefinition.hh"
#include "yaml-cpp/yaml.h"
#include "RHEJ/event_types.hh"
#include "RHEJ/Event.hh"
#include "RHEJ/HiggsCouplingSettings.hh"
#include "RHEJ/optional.hh"
#include "RHEJ/output_formats.hh"
#include "RHEJ/ScaleFunction.hh"
#include "RHEJ/utility.hh"
namespace RHEJ{
/**! \struct JetParameters config.hh "include/RHEJ/config.hh"
* \brief Contains Jet Definition and Minimum Pt to be a Jet.
*
* Contains the Fastjet definition of a Jet and a threshold (minimum) value for pt
*/
struct JetParameters{
fastjet::JetDefinition def; /**< Jet Definition */
double min_pt; /**< Minimum Jet Pt */
};
/**! \struct ScaleConfig config.hh "include/RHEJ/config.hh"
* \brief Sets up the possible choices for scale variation?
*
* There is a vector which contains the possible scale choices and
* also vector of doubles with the scale factors along with a max
* scale ratio.
*/
struct ScaleConfig{
- // std::vector<std::unique_ptr<ScaleFunction>> scales; /**< Vector of possible Scale choices */
std::vector<std::shared_ptr<ScaleFunction>> scales; /**< Vector of possible Scale choices */
std::vector<double> scale_factors; /**< Vector of possible Scale Factors */
double max_scale_ratio; /**< Maximum ratio for the scales */
};
/**! \class ScaleGenerator config.hh "include/RHEJ/config.hh"
* \brief A Class used to generate scales
*
* This class has a clustered event class and scale config struct
* within it.
*/
class ScaleGenerator{
public:
ScaleGenerator() = default;
explicit ScaleGenerator(ScaleConfig && settings):
settings_{std::move(settings)}
{}
Event operator()(Event ev) const;
ScaleConfig const & settings() const;
private:
ScaleConfig settings_;
};
/**! \enum EventTreatment config.hh "include/RHEJ/config.hh"
* \brief Enumeration which deals with how to treat events.
*
* The program will decide on how to treat an event based on
* the value of this enumeration.
*/
enum class EventTreatment{
reweight, /**< Reweigh the event */
keep, /**< Keep the event */
discard, /**< Discard the event */
};
/**
* \brief An ordered Map with EventType keys and mapped values EventTreatment
*
* If called upon with EventTreatMap.at(EventType) it will return the treatment which has
* been specified for that EventType.
*/
using EventTreatMap = std::map<event_type::EventType, EventTreatment>;
/**! \struct Config config.hh "include/RHEJ/config.hh"
* \brief Config Struct for user input parameters.
*
* The struct which handles the input card given by the user.
*
* \internal To add a new option:
* 1. Add a member to the Config struct.
* 2. Inside "src/YAMLreader.cc":
* - Add the option name to the "supported" Node in
* get_supported_options.
* - Initialise the new Config member in to_Config.
* The functions set_from_yaml (for mandatory options) and
* set_from_yaml_if_defined (non-mandatory) may be helpful.
* 3. Add a new entry (with short description) to config.yaml
*/
struct Config {
ScaleGenerator scale_gen; /**< Scale */
JetParameters resummation_jets; /**< Resummation Jets */
JetParameters fixed_order_jets; /**< Fixed-Order Jets */
double min_extparton_pt; /**< Min External Parton Pt*/
double max_ext_soft_pt_fraction; /**< Min External Parton Pt Fraction */
int trials; /**< Number of resummation points to generate per FO */
//! Log Correct from running of \f$\alpha_s$\f On or Off
bool log_correction;
bool unweight; /**< Unweight On or Off */
std::vector<OutputFile> output; /**< Output Files Type */
optional<std::string> RanLux_init; /**< Ranlux File Choice*/
//! Map to decide what to do for differnt EventTypes
EventTreatMap treat;
YAML::Node analysis_parameters; /**< Analysis Parameters */
//! Settings for Effective Higgs-Gluon Coupling
HiggsCouplingSettings Higgs_coupling;
};
class Parameters{
protected:
const Config & config;
public:
explicit Parameters(const Config & conf): config(conf){}
- // explicit Parameters(const Parameters & param):
- // config(param.getConfig()){}
const Config & get_Config() const {return config;}
};
class PhaseSpacePointParameters: public Parameters {
public:
explicit PhaseSpacePointParameters(const Config & conf): Parameters(conf){}
///@{
/// @name getter functions
const JetParameters & jet_parameters() const
{return config.resummation_jets;}
double jet_ptmin() const
{return jet_parameters().min_pt;}
const fastjet::JetDefinition & jet_def() const
{return jet_parameters().def;}
double jet_R() const
{return jet_def().R();}
double min_ext_pt() const
{return config.min_extparton_pt;}
double max_ext_soft_pt_fraction() const
{return config.max_ext_soft_pt_fraction;}
///@}
};
class MartixElementParameters: public Parameters {
public:
explicit MartixElementParameters(const Config & conf):
Parameters(conf){}
///@{
/// @name getter functions
const JetParameters & jet_parameters() const
{return config.resummation_jets;}
double jet_ptmin() const
{return jet_parameters().min_pt;}
const fastjet::JetDefinition & jet_def() const
{return jet_parameters().def;}
bool log_corr() const
{return config.log_correction;}
const HiggsCouplingSettings & Hgg_setting() const
{return config.Higgs_coupling;}
///@}
};
class EventReweighterParameters: public Parameters {
public:
explicit EventReweighterParameters(const Config & conf):
Parameters(conf){}
///@{
/// @name getter functions
const JetParameters & jet_parameters() const
{return config.resummation_jets;}
double jet_ptmin() const
{return jet_parameters().min_pt;}
const fastjet::JetDefinition & jet_def() const
{return jet_parameters().def;}
const EventTreatMap & treat() const
{return config.treat;}
///@}
};
} // namespace RHEJ
diff --git a/src/MatrixElement.cc b/src/MatrixElement.cc
index f5062a8..dd636dd 100644
--- a/src/MatrixElement.cc
+++ b/src/MatrixElement.cc
@@ -1,758 +1,748 @@
#include "RHEJ/MatrixElement.hh"
#include <CLHEP/Random/Randomize.h>
#include <CLHEP/Random/RanluxEngine.h>
+#include "RHEJ/Constants.hh"
#include "RHEJ/currents.hh"
#include "RHEJ/PDG_codes.hh"
#include "RHEJ/uno.hh"
#include "RHEJ/debug.hh"
-
-namespace{
- constexpr int N_C = 3;
- constexpr int C_A = N_C;
- constexpr double C_F = (N_C*N_C - 1.)/(2.*N_C);
- constexpr double t_f = 1./2.;
- constexpr double clambda = 0.2;
- constexpr int n_f = 5;
- constexpr double beta0 = 11./3.*C_A - 4./3.*t_f*n_f;
-}
-
namespace RHEJ{
//cf. last line of eq. (22) in \ref Andersen:2011hs
double MatrixElement::omega0(
double alpha_s, double mur,
fastjet::PseudoJet const & q_j, double lambda
) const {
const double result = - alpha_s*N_C/M_PI*log(q_j.perp2()/(lambda*lambda));
if(! param.log_corr()) 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;
}
double MatrixElement::virtual_corrections(
double mur,
std::array<Sparticle, 2> const & in,
std::vector<Sparticle> const & out
) const{
fastjet::PseudoJet const & pa = in.front().p;
#ifndef NDEBUG
fastjet::PseudoJet const & pb = in.back().p;
#endif
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 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 || has_unob_gluon(in, out)){
q -= out[1].p;
++first_idx;
}
if(out.back().type == pid::Higgs || has_unof_gluon(in, out)){
--last_idx;
}
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, clambda)*(
+ exponent += omega0(alpha_s, mur, q, CLAMBDA)*(
out[j+1].rapidity() - out[j].rapidity()
);
q -= out[j+1].p;
}
assert(
nearby(q, -1*pb)
|| out.back().type == pid::Higgs
|| has_unof_gluon(in, out)
);
return exp(exponent);
}
}
namespace {
//! Lipatov vertex for partons emitted into extremal jets
double C2Lipatov(CLHEP::HepLorentzVector qav, CLHEP::HepLorentzVector qbv, CLHEP::HepLorentzVector p1, CLHEP::HepLorentzVector p2)
{
CLHEP::HepLorentzVector temptrans=-(qav+qbv);
CLHEP::HepLorentzVector p5=qav-qbv;
CLHEP::HepLorentzVector CL=temptrans+(qav.m2()/p5.dot(p1)+2.*p5.dot(p2)/p1.dot(p2))*p1-p2*(qbv.m2()/p5.dot(p2)+2.*p5.dot(p1)/p1.dot(p2));
#if printoutput
cout << "#Fadin qa : "<<qav<<endl;
cout << "#Fadin qb : "<<qbv<<endl;
cout << "#Fadin p1 : "<<p1<<endl;
cout << "#Fadin p2 : "<<p2<<endl;
cout << "#Fadin p5 : "<<p5<<endl;
cout << "#Fadin Gauge Check : "<< CL.dot(p5)<<endl;
cout << "#Fadin C2L : "<< -CL.dot(CL)<<" "<<-CL.dot(CL)/(qav.m2()*qbv.m2())/(4./p5.perp2())<<endl;
#endif
#if 0
if (-CL.dot(CL)<0.)
// if (fabs(CL.dot(p5))>fabs(CL.dot(CL))) // not sufficient!
return 0.;
else
#endif
return -CL.dot(CL);
}
//! Lipatov vertex with soft subtraction for partons emitted into extremal jets
double C2Lipatovots(CLHEP::HepLorentzVector qav, CLHEP::HepLorentzVector qbv, CLHEP::HepLorentzVector p1, CLHEP::HepLorentzVector p2)
{
double kperp=(qav-qbv).perp();
- if (kperp>clambda)
+ if (kperp>RHEJ::CLAMBDA)
return C2Lipatov(qav, qbv, p1, p2)/(qav.m2()*qbv.m2());
else {
double Cls=(C2Lipatov(qav, qbv, p1, p2)/(qav.m2()*qbv.m2()));
double temp=Cls-4./(kperp*kperp);
// std::cout <<kperp <<" "<<temp<<" "<<4./(kperp*kperp)<<" "<<(C2Lipatov(qav, qbv, pa, pb, p1, p2)/(qav.m2()*qbv.m2()))<<std::endl;
return temp;
}
}
//! Lipatov vertex
double C2Lipatov(CLHEP::HepLorentzVector qav, CLHEP::HepLorentzVector qbv, CLHEP::HepLorentzVector pim, CLHEP::HepLorentzVector pip,CLHEP::HepLorentzVector pom, CLHEP::HepLorentzVector pop) // B
{
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 qav, CLHEP::HepLorentzVector qbv, CLHEP::HepLorentzVector pa, CLHEP::HepLorentzVector pb, CLHEP::HepLorentzVector p1, CLHEP::HepLorentzVector p2)
{
double kperp=(qav-qbv).perp();
- if (kperp>clambda)
+ if (kperp>RHEJ::CLAMBDA)
return C2Lipatov(qav, qbv, pa, pb, p1, p2)/(qav.m2()*qbv.m2());
else {
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 jM2gg(pn,pb,p1,pa);
} else if (aptype==21&&bptype!=21) {
if (bptype > 0)
return jM2qg(pn,pb,p1,pa);
else
return jM2qbarg(pn,pb,p1,pa);
}
else if (bptype==21&&aptype!=21) { // ----- || -----
if (aptype > 0)
return jM2qg(p1,pa,pn,pb);
else
return jM2qbarg(p1,pa,pn,pb);
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
return jM2qQ(pn,pb,p1,pa);
else
return jM2qQbar(pn,pb,p1,pa);
}
else {
if (aptype>0)
return jM2qQbar(p1,pa,pn,pb);
else
return jM2qbarQbar(pn,pb,p1,pa);
}
}
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 MH2gg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else if (aptype==21&&bptype!=21) {
if (bptype > 0)
return MH2qg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4./9.;
else
return MH2qbarg(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4./9.;
}
else if (bptype==21&&aptype!=21) {
if (aptype > 0)
return MH2qg(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4./9.;
else
return MH2qbarg(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4./9.;
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
return MH2qQ(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4.*4./(9.*9.);
else
return MH2qQbar(pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb)*4.*4./(9.*9.);
}
else {
if (aptype>0)
return MH2qQbar(p1,pa,pn,pb,-qH,-qHp1,mt,include_bottom,mb)*4.*4./(9.*9.);
else
return MH2qbarQbar(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 jM2unogqHg(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unogqbarHg(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
}
else { // they are both quark
if (bptype>0) {
if (aptype>0)
return jM2unogqHQ(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unogqHQbar(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
}
else {
if (aptype>0)
return jM2unogqbarHQ(punof,pn,pb,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unogqbarHQbar(punof,pn,pb,p1,pa,-qHp1,-qH,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 jM2unobgHQg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unobgHQbarg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
}
else { // they are both quark
if (aptype>0) {
if (bptype>0)
return jM2unobqHQg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unobqbarHQg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
}
else {
if (bptype>0)
return jM2unobqHQbarg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
else
return jM2unobqbarHQbarg(pn,pb,punob,p1,pa,-qHp1,-qH,mt,include_bottom,mb);
}
}
throw std::logic_error("unknown particle types");
}
CLHEP::HepLorentzVector to_HepLorentzVector(RHEJ::Sparticle const & particle){
return {particle.p.px(), particle.p.py(), particle.p.pz(), particle.p.E()};
}
} // namespace RHEJ
namespace RHEJ{
MatrixElement::MatrixElement(
std::function<double (double)> alpha_s,
Config const & conf
):
alpha_s_{std::move(alpha_s)},
param(conf)
{}
double MatrixElement::operator()(
double mur,
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
return tree(
mur,
incoming, outgoing,
check_momenta
)*virtual_corrections(
mur,
incoming, outgoing
);
}
double MatrixElement::tree_kin(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
assert(
std::is_sorted(
incoming.begin(), incoming.end(),
[](Sparticle o1, Sparticle o2){return o1.p.pz()<o2.p.pz();}
)
);
assert(std::is_sorted(outgoing.begin(), outgoing.end(), rapidity_less{}));
auto AWZH_boson = std::find_if(
begin(outgoing), end(outgoing),
[](Sparticle const & p){return is_AWZH_boson(p);}
);
if(AWZH_boson == end(outgoing)){
return tree_kin_jets(incoming, outgoing, check_momenta);
}
switch(AWZH_boson->type){
case pid::Higgs: {
static constexpr double mH = 125.;
const double alpha_s_mH = alpha_s_(mH);
return alpha_s_mH*alpha_s_mH/(256.*pow(M_PI, 5))*tree_kin_Higgs(
incoming, outgoing, check_momenta
);
}
// TODO
case pid::Wp:
case pid::Wm:
case pid::photon:
case pid::Z:
default:
throw std::logic_error("Emission of boson of unsupported type");
}
}
namespace{
constexpr int extremal_jet_idx = 1;
constexpr int no_extremal_jet_idx = 0;
bool treat_as_extremal(Sparticle 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 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)*C_A;
} else{
wt *= C2Lipatovots(qip1, qi, pa, pb, p1, pn)*C_A;
}
qi = qip1;
}
return wt;
}
} // namespace anonymous
std::vector<Sparticle> MatrixElement::tag_extremal_jet_partons(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> out_partons, bool check_momenta
) const{
if(!check_momenta){
for(auto & parton: out_partons){
parton.p.set_user_index(no_extremal_jet_idx);
}
return out_partons;
}
fastjet::ClusterSequence cs(to_PseudoJet(out_partons), param.jet_def());
const auto jets = sorted_by_rapidity(cs.inclusive_jets(param.jet_ptmin()));
assert(jets.size() >= 2);
auto most_backward = begin(jets);
auto most_forward = end(jets) - 1;
// skip jets caused by unordered emission
if(has_unob_gluon(incoming, out_partons)){
assert(jets.size() >= 3);
++most_backward;
}
else if(has_unof_gluon(incoming, out_partons)){
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(RHEJ::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(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> partons,
bool check_momenta
) const {
partons = tag_extremal_jet_partons(incoming, partons, check_momenta);
if(has_unob_gluon(incoming, partons) || has_unof_gluon(incoming, partons)){
throw std::logic_error("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
);
}
double MatrixElement::tree_kin_Higgs(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
if(has_uno_gluon(incoming, outgoing)){
return tree_kin_Higgs_between(incoming, outgoing, check_momenta);
}
if(outgoing.front().type == pid::Higgs){
return tree_kin_Higgs_first(incoming, outgoing, check_momenta);
}
if(outgoing.back().type == pid::Higgs){
return tree_kin_Higgs_last(incoming, outgoing, check_momenta);
}
return tree_kin_Higgs_between(incoming, outgoing, check_momenta);
}
double MatrixElement::MH2_forwardH(
RHEJ::ParticleID id,
CLHEP::HepLorentzVector p1out, CLHEP::HepLorentzVector p1in,
CLHEP::HepLorentzVector p2out, CLHEP::HepLorentzVector p2in,
CLHEP::HepLorentzVector pH,
double t1, double t2
) const{
ignore(p2out, p2in);
const double shat = p1in.invariantMass2(p2in);
assert(RHEJ::is_parton(id));
if(id != RHEJ::pid::gluon){
return 9./2.*shat*shat*C2qHqm(p1in,p1out,pH)/(t1*t2);
}
// gluon case
#ifdef RHEJ_BUILD_WITH_QCDLOOP
if(!param.Hgg_setting().use_impact_factors){
return C_A/C_F*1./(16*M_PI*M_PI)*t1/t2*MH2gq_outsideH(
p1out, p1in, p2out, p2in, pH,
param.Hgg_setting().mt, param.Hgg_setting().include_bottom,
param.Hgg_setting().mb
);
}
#endif
return 9./2.*shat*shat*(
C2gHgp(p1in,p1out,pH) + C2gHgm(p1in,p1out,pH)
)/(t1*t2);
}
double MatrixElement::tree_kin_Higgs_first(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
assert(outgoing.front().type == pid::Higgs);
const auto pH = to_HepLorentzVector(outgoing.front());
const auto partons = tag_extremal_jet_partons(
incoming,
std::vector<Sparticle>(begin(outgoing) + 1, end(outgoing)),
check_momenta
);
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();
double wt = MH2_forwardH(
incoming[0].type, p1, pa, pn, pb, pH,
t1, t2
)*FKL_ladder_weight(
begin(partons) + 1, end(partons) - 1,
q0, pa, pb, p1, pn
);
for(auto const & inc: incoming){
if(inc.type != pid::gluon) wt *= C_F/C_A;
}
return wt;
}
double MatrixElement::tree_kin_Higgs_last(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
assert(outgoing.back().type == pid::Higgs);
const auto pH = to_HepLorentzVector(outgoing.back());
const auto partons = tag_extremal_jet_partons(
incoming,
std::vector<Sparticle>(begin(outgoing), end(outgoing) - 1),
check_momenta
);
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();
double wt = MH2_forwardH(
incoming[1].type, pn, pb, p1, pa, pH,
t2, t1
)*FKL_ladder_weight(
begin(partons) + 1, end(partons) - 1,
q0, pa, pb, p1, pn
);
for(auto const & inc: incoming){
if(inc.type != pid::gluon) wt *= C_F/C_A;
}
return wt;
}
double MatrixElement::tree_kin_Higgs_between(
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
const auto the_Higgs = std::find_if(
begin(outgoing), end(outgoing),
[](Sparticle const & s){ return s.type == pid::Higgs; }
);
assert(the_Higgs != end(outgoing));
const auto pH = to_HepLorentzVector(*the_Higgs);
std::vector<Sparticle> partons(begin(outgoing), the_Higgs);
partons.insert(end(partons), the_Higgs + 1, end(outgoing));
partons = tag_extremal_jet_partons(incoming, partons, check_momenta);
const auto pa = to_HepLorentzVector(incoming[0]);
const auto pb = to_HepLorentzVector(incoming[1]);
auto p1 = to_HepLorentzVector(
partons[has_unob_gluon(incoming, outgoing)?1:0]
);
auto pn = to_HepLorentzVector(
partons[partons.size() - (has_unof_gluon(incoming, outgoing)?2:1)]
);
auto first_after_Higgs = begin(partons) + (the_Higgs-begin(outgoing));
assert(
(first_after_Higgs == end(partons) && has_unob_gluon(incoming, outgoing))
|| first_after_Higgs->rapidity() >= the_Higgs->rapidity()
);
assert(
(first_after_Higgs == begin(partons) && has_unof_gluon(incoming, outgoing))
|| (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(has_unob_gluon(incoming, outgoing)){
current_factor = 9./2.*ME_Higgs_current_unob(
incoming[0].type, incoming[1].type,
pn, pb, to_HepLorentzVector(partons.front()), p1, pa, qH, qH - pH,
param.Hgg_setting().mt, param.Hgg_setting().include_bottom, param.Hgg_setting().mb
);
const auto p_unob = to_HepLorentzVector(partons.front());
q0 -= p_unob;
p1 += p_unob;
++begin_ladder;
}
else if(has_unof_gluon(incoming, outgoing)){
current_factor = 9./2.*ME_Higgs_current_unof(
incoming[0].type, incoming[1].type,
to_HepLorentzVector(partons.back()), pn, pb, p1, pa, qH, qH - pH,
param.Hgg_setting().mt, param.Hgg_setting().include_bottom, param.Hgg_setting().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.Hgg_setting().mt, param.Hgg_setting().include_bottom, param.Hgg_setting().mb
);
}
const double ladder_factor = FKL_ladder_weight(
begin_ladder, first_after_Higgs,
q0, pa, pb, p1, pn
)*FKL_ladder_weight(
first_after_Higgs, end_ladder,
qH - pH, pa, pb, p1, pn
);
return current_factor*9./8.*ladder_factor;
}
double MatrixElement::tree_param_partons(
double alpha_s, double mur,
std::vector<Sparticle> const & partons
) const{
const double gs2 = 4.*M_PI*alpha_s;
double wt = std::pow(gs2, partons.size());
if(param.log_corr()){
// use alpha_s(q_perp), evolved to mur
assert(partons.size() >= 2);
for(size_t i = 1; i < partons.size()-1; ++i){
wt *= 1 + alpha_s/(2*M_PI)*beta0*log(mur/partons[i].p.perp());
}
}
return wt;
}
double MatrixElement::tree_param(
double mur,
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing
) const{
const double alpha_s = alpha_s_(mur);
if(has_unob_gluon(incoming, outgoing)){
return 4*M_PI*alpha_s*tree_param_partons(
alpha_s, mur, filter_partons({begin(outgoing) + 1, end(outgoing)})
);
}
if(has_unof_gluon(incoming, outgoing)){
return 4*M_PI*alpha_s*tree_param_partons(
alpha_s, mur, filter_partons({begin(outgoing), end(outgoing) - 1})
);
}
return tree_param_partons(alpha_s, mur, filter_partons(outgoing));
}
double MatrixElement::tree(
double mur,
std::array<Sparticle, 2> const & incoming,
std::vector<Sparticle> const & outgoing,
bool check_momenta
) const {
return tree_param(mur, incoming, outgoing)*tree_kin(
incoming, outgoing, check_momenta
);
}
} // namespace RHEJ
diff --git a/src/PhaseSpacePoint.cc b/src/PhaseSpacePoint.cc
index 2be3323..1ecd7c3 100644
--- a/src/PhaseSpacePoint.cc
+++ b/src/PhaseSpacePoint.cc
@@ -1,580 +1,581 @@
#include "RHEJ/PhaseSpacePoint.hh"
#include <random>
+#include "RHEJ/Constants.hh"
#include "RHEJ/resummation_jet_momenta.hh"
#include "RHEJ/Jacobian.hh"
#include "RHEJ/RNGWrapper.hh"
#include "RHEJ/uno.hh"
#include "RHEJ/debug.hh"
#include "RHEJ/kinematics.hh"
namespace RHEJ{
namespace{
//generate Ranlux64Engine with fixed, predefined state
/*
* some (all?) of the Ranlux64Engine constructors leave fields
* uninitialised, invoking undefined behaviour. This can be
* circumvented by restoring the state from a file
*/
CLHEP::Ranlux64Engine gen_Ranlux64Engine(){
static const std::string state =
"9876\n"
"0.91280703978419097666\n"
"0.41606065829518357191\n"
"0.99156342622341142601\n"
"0.030922955274050423213\n"
"0.16206278421638486975\n"
"0.76151768001958330956\n"
"0.43765760066092695979\n"
"0.42904698253748563275\n"
"0.11476317525663759511\n"
"0.026620053590963976831\n"
"0.65953715764414511114\n"
"0.30136722624439826745\n"
"3.5527136788005009294e-15 4\n"
"1 202\n";
const std::string file = std::tmpnam(nullptr);
{
std::ofstream out{file};
out << state;
}
CLHEP::Ranlux64Engine result;
result.restoreStatus(file.c_str());
return result;
}
}
CLHEP::Ranlux64Engine PhaseSpacePoint::ran_{gen_Ranlux64Engine()};
void PhaseSpacePoint::reset_ranlux(std::string const & init_file){
reset_ranlux(init_file.c_str());
}
void PhaseSpacePoint::reset_ranlux(char const * init_file){
ran_.restoreStatus(init_file);
}
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;
}
// user indices for partons with extremal rapidity
constexpr int unob_idx = -5;
constexpr int unof_idx = -4;
constexpr int backward_FKL_idx = -3;
constexpr int forward_FKL_idx = -2;
}
namespace{
double estimate_ng_mean(std::vector<fastjet::PseudoJet> const & Born_jets){
const double delta_y =
Born_jets.back().rapidity() - Born_jets.front().rapidity();
assert(delta_y > 0);
// Formula derived from fit in reversed HEJ intro paper
return 0.975052*delta_y;
}
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::cluster_jets(
std::vector<fastjet::PseudoJet> const & partons
) const{
fastjet::ClusterSequence cs(partons, param.jet_def());
return cs.inclusive_jets(param.jet_ptmin());
}
bool PhaseSpacePoint::pass_resummation_cuts(
std::vector<fastjet::PseudoJet> const & jets
) const{
return cluster_jets(jets).size() == jets.size();
}
int PhaseSpacePoint::sample_ng(std::vector<fastjet::PseudoJet> const & Born_jets){
const double ng_mean = estimate_ng_mean(Born_jets);
std::poisson_distribution<int> dist(ng_mean);
RNGWrapper<CLHEP::Ranlux64Engine> rng{ran_};
const int ng = dist(rng);
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::copy_AWZH_boson_from(Event const & event){
auto const & from = event.outgoing();
const auto AWZH_boson = std::find_if(
begin(from), end(from),
[](Sparticle const & p){ return is_AWZH_boson(p); }
);
if(AWZH_boson == end(from)) return;
auto insertion_point = std::lower_bound(
begin(outgoing_), end(outgoing_), *AWZH_boson, rapidity_less{}
);
outgoing_.insert(insertion_point, *AWZH_boson);
// copy decay products
const int idx = std::distance(begin(from), AWZH_boson);
const auto decay_it = event.decays().find(idx);
if(decay_it != end(event.decays())){
const int new_idx = std::distance(begin(outgoing_), insertion_point);
assert(outgoing_[new_idx].type == AWZH_boson->type);
decays_.emplace(new_idx, decay_it->second);
}
assert(std::is_sorted(begin(outgoing_), end(outgoing_), rapidity_less{}));
}
PhaseSpacePoint::PhaseSpacePoint(Event const & ev, Config const & conf):
unob_{has_unob_gluon(ev.incoming(), ev.outgoing())},
unof_{!unob_ && has_unof_gluon(ev.incoming(), ev.outgoing())},
param(conf),
splitter_{param.jet_R(), param.jet_def(), param.jet_ptmin(), ran_}
{
weight_ = 1;
const auto Born_jets = sorted_by_rapidity(ev.jets());
const int ng = sample_ng(Born_jets);
weight_ /= std::tgamma(ng + 1);
const int ng_jets = sample_ng_jets(ng, Born_jets);
std::vector<fastjet::PseudoJet> out_partons = gen_non_jet(
- ng - ng_jets, ccut, param.jet_ptmin()
+ ng - ng_jets, CMINPT, param.jet_ptmin()
);
{
const auto qperp = std::accumulate(
begin(out_partons), end(out_partons),
fastjet::PseudoJet{}
);
const auto jets = reshuffle(Born_jets, qperp);
if(weight_ == 0.) return;
if(! pass_resummation_cuts(jets)){
weight_ = 0.;
return;
}
std::vector<fastjet::PseudoJet> jet_partons = split(jets, ng_jets);
if(weight_ == 0.) return;
rescale_rapidities(
out_partons,
most_backward_FKL(jet_partons).rapidity(),
most_forward_FKL(jet_partons).rapidity()
);
if(! cluster_jets(out_partons).empty()){
weight_ = 0.;
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(Born_jets, out_partons)){
weight_ = 0.;
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 & p: out_partons){
outgoing_.emplace_back(Sparticle{pid::gluon, std::move(p)});
}
most_backward_FKL(outgoing_).type = ev.incoming().front().type;
most_forward_FKL(outgoing_).type = ev.incoming().back().type;
copy_AWZH_boson_from(ev);
assert(!outgoing_.empty());
reconstruct_incoming(ev.incoming());
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::gen_non_jet(
int count, double ptmin, double ptmax
){
// heuristic parameters for pt sampling
const double ptpar = 1.3 + count/5.;
const double temp1 = atan((ptmax - ptmin)/ptpar);
std::vector<fastjet::PseudoJet> partons(count);
for(size_t i = 0; i < (size_t) count; ++i){
const double r1 = ran_.flat();
const double pt = ptmin + ptpar*tan(r1*temp1);
const double temp2 = 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 + RHEJ::PhaseSpacePoint::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 partons;
}
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(
std::vector<fastjet::PseudoJet> const & Born_jets
) const{
assert(std::is_sorted(begin(Born_jets), end(Born_jets), rapidity_less{}));
assert(Born_jets.size() >= 2);
const double dy =
Born_jets.back().rapidity() - Born_jets.front().rapidity();
const double R = param.jet_R();
const int njets = Born_jets.size();
const double p_J_y_large = (njets-1)*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(
int ng, std::vector<fastjet::PseudoJet> const & Born_jets
){
RNGWrapper<CLHEP::Ranlux64Engine> rng{ran_};
const double p_J = probability_in_jet(Born_jets);
std::binomial_distribution<> bin_dist(ng, p_J);
const int ng_J = bin_dist(rng);
weight_ *= std::pow(p_J, -ng_J)*std::pow(1 - p_J, ng_J - ng);
return ng_J;
}
std::vector<fastjet::PseudoJet>
PhaseSpacePoint::reshuffle(
std::vector<fastjet::PseudoJet> const & Born_jets,
fastjet::PseudoJet const & q
){
if(q == fastjet::PseudoJet{0, 0, 0, 0}) return Born_jets;
std::vector<fastjet::PseudoJet> jets = resummation_jet_momenta(Born_jets, q);
if(jets.empty()){
weight_ = 0;
return {};
}
// transform delta functions to integration over resummation momenta
weight_ /= Jacobian(jets, q);
return jets;
}
std::vector<int> PhaseSpacePoint::distribute_jet_partons(
int ng_jets, std::vector<fastjet::PseudoJet> const & jets
){
size_t first_valid_jet = 0;
size_t num_valid_jets = jets.size();
const double R_eff = 5./3.*param.jet_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_ && jets[0].delta_R(jets[1]) > R_eff){
++first_valid_jet;
--num_valid_jets;
}
else if(unof_ && 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() == backward_FKL_idx;
}
) != 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() == forward_FKL_idx;
}
) != jet_partons.rend();
}
bool tagged_FKL_extremal(
std::vector<fastjet::PseudoJet> const & jet_partons
){
return tagged_FKL_backward(jet_partons) && tagged_FKL_forward(jet_partons);
}
} // namespace anonymous
#endif
std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
std::vector<fastjet::PseudoJet> const & jets,
int ng_jets
){
return split(jets, distribute_jet_partons(ng_jets, jets));
}
bool PhaseSpacePoint::pass_extremal_cuts(
fastjet::PseudoJet const & ext_parton,
fastjet::PseudoJet const & jet
) const{
if(ext_parton.pt() < param.min_ext_pt()) return false;
return (ext_parton - jet).pt()/jet.pt() < param.max_ext_soft_pt_fraction();
}
std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
std::vector<fastjet::PseudoJet> const & jets,
std::vector<int> const & np
){
assert(! jets.empty());
assert(jets.size() == np.size());
assert(pass_resummation_cuts(jets));
const size_t most_backward_FKL_idx = 0 + unob_;
const size_t most_forward_FKL_idx = jets.size() - 1 - unof_;
std::vector<fastjet::PseudoJet> jet_partons;
// randomly distribute jet gluons among jets
for(size_t i = 0; i < jets.size(); ++i){
weight_ *= splitter_.Split(jets[i], np[i]);
if(weight_ == 0) return {};
assert(
std::all_of(
begin(splitter_.get_jcons()), end(splitter_.get_jcons()),
is_jet_parton
)
);
const auto first_new_parton = jet_partons.insert(
end(jet_partons),
begin(splitter_.get_jcons()), end(splitter_.get_jcons())
);
// mark uno and extremal FKL emissions here so we can check
// their position once all emissions are generated
auto extremal = end(jet_partons);
if((unob_ && i == 0) || i == most_backward_FKL_idx){
// unordered or FKL backward emission
extremal = std::min_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(
(i == most_backward_FKL_idx)?backward_FKL_idx:unob_idx
);
}
else if((unof_ && i == jets.size() - 1) || i == most_forward_FKL_idx){
// unordered or FKL forward emission
extremal = std::max_element(
first_new_parton, end(jet_partons), rapidity_less{}
);
extremal->set_user_index(
(i == most_forward_FKL_idx)?forward_FKL_idx:unof_idx
);
}
if(
extremal != end(jet_partons)
&& !pass_extremal_cuts(*extremal, jets[i])
){
weight_ = 0;
return {};
}
}
assert(tagged_FKL_extremal(jet_partons));
std::sort(begin(jet_partons), end(jet_partons), rapidity_less{});
if(
!extremal_ok(jet_partons)
|| !split_preserved_jets(jets, jet_partons)
){
weight_ = 0.;
return {};
}
return jet_partons;
}
bool PhaseSpacePoint::extremal_ok(
std::vector<fastjet::PseudoJet> const & partons
) const{
assert(std::is_sorted(begin(partons), end(partons), rapidity_less{}));
if(unob_ && partons.front().user_index() != unob_idx) return false;
if(unof_ && partons.back().user_index() != unof_idx) return false;
return
most_backward_FKL(partons).user_index() == backward_FKL_idx
&& most_forward_FKL(partons).user_index() == forward_FKL_idx;
}
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 = sorted_by_rapidity(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_];
}
template<class Particle>
Particle const & PhaseSpacePoint::most_forward_FKL(
std::vector<Particle> const & partons
) const{
const size_t idx = partons.size() - 1 - unof_;
assert(idx < partons.size());
return partons[idx];
}
template<class Particle>
Particle & PhaseSpacePoint::most_backward_FKL(
std::vector<Particle> & partons
) const{
return partons[0 + unob_];
}
template<class Particle>
Particle & PhaseSpacePoint::most_forward_FKL(
std::vector<Particle> & partons
) const{
const size_t idx = partons.size() - 1 - unof_;
assert(idx < partons.size());
return partons[idx];
}
namespace{
bool contains_idx(
fastjet::PseudoJet const & jet, fastjet::PseudoJet const & parton
){
auto const & constituents = jet.constituents();
const int idx = parton.user_index();
return std::find_if(
begin(constituents), end(constituents),
[idx](fastjet::PseudoJet const & con){return con.user_index() == idx;}
) != end(constituents);
}
}
/**
* final jet test:
* - number of jets must match Born kinematics
* - no partons designated as nonjet may end up inside jets
* - all other outgoing partons *must* end up inside jets
* - the extremal (in rapidity) partons must be inside the extremal jets
* - rapidities must be the same (by construction)
*/
bool PhaseSpacePoint::jets_ok(
std::vector<fastjet::PseudoJet> const & Born_jets,
std::vector<fastjet::PseudoJet> const & partons
) const{
fastjet::ClusterSequence cs(partons, param.jet_def());
const auto jets = sorted_by_rapidity(cs.inclusive_jets(param.jet_ptmin()));
if(jets.size() != Born_jets.size()) return false;
int in_jet = 0;
for(size_t i = 0; i < jets.size(); ++i){
assert(jets[i].has_constituents());
for(auto && parton: jets[i].constituents()){
if(is_nonjet_parton(parton)) return false;
}
in_jet += jets[i].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(! (
contains_idx(most_backward_FKL(jets), most_backward_FKL(partons))
&& contains_idx(most_forward_FKL(jets), most_forward_FKL(partons))
)) return false;
if(unob_ && !contains_idx(jets.front(), partons.front())) return false;
if(unof_ && !contains_idx(jets.back(), partons.back())) return false;
for(size_t i = 0; i < jets.size(); ++i){
assert(nearby_ep(jets[i].rapidity(), Born_jets[i].rapidity(), 1e-2));
}
return true;
}
namespace{
}
void PhaseSpacePoint::reconstruct_incoming(
std::array<Sparticle, 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(1e-7));
}
double PhaseSpacePoint::phase_space_normalisation(
int num_Born_jets, int num_out_partons
) const{
return pow(16*pow(M_PI,3), num_Born_jets - num_out_partons);
}
bool PhaseSpacePoint::momentum_conserved(double ep) const{
fastjet::PseudoJet diff;
for(auto const & in: incoming()) diff += in.p;
for(auto const & out: outgoing()) diff -= out.p;
return nearby_ep(diff, fastjet::PseudoJet{}, ep);
}
}
diff --git a/src/Splitter.cc b/src/Splitter.cc
index 512bfca..0be5546 100644
--- a/src/Splitter.cc
+++ b/src/Splitter.cc
@@ -1,210 +1,211 @@
/**
* Name: splitter.cc
* Author: Tuomas Hapola
*
* double Sample2jetPartons(int * np);
* bool Split(fastjet::PseudoJet j2split, int ncons);
* bool DistributeQperp(fastjet::PseudoJet qperp, int np, double miny, double maxy);
* void PrintConstituentInfo(std::vector<fastjet::PseudoJet> jets);
*
*/
#include <numeric>
+#include "RHEJ/Constants.hh"
#include "RHEJ/Splitter.hh"
#include "RHEJ/PhaseSpacePoint.hh"
namespace{
- constexpr double ccut=0.2; // min parton pt
+ constexpr double ccut=RHEJ::CMINPT; // min parton pt
template<class Iterator>
bool same_pt_and_rapidity(
Iterator begin, Iterator end,
fastjet::PseudoJet const & jet
){
static constexpr double ep = 1e-2;
const fastjet::PseudoJet reconstructed_jet = std::accumulate(
begin, end, fastjet::PseudoJet{}
);
return
(std::abs(reconstructed_jet.pt() - jet.pt()) < ep)
&& (std::abs(reconstructed_jet.rapidity() - jet.rapidity()) < ep)
;
}
bool all_in_one_jet(
std::vector<fastjet::PseudoJet> const & partons,
fastjet::JetDefinition jet_def, double min_jet_pt
){
fastjet::ClusterSequence ev(partons, jet_def);
const std::vector<fastjet::PseudoJet> testjet = ev.inclusive_jets(min_jet_pt);
return testjet.size() == 1u
&& testjet[0].constituents().size() == partons.size();
}
}
double HejSplit::Split(fastjet::PseudoJet const & j2split, int ncons){
assert(ncons >= 1);
double swt = 1.;
jcons.clear();
jcons.reserve(ncons);
if(ncons == 1){
jcons.emplace_back(j2split);
jcons.back().set_user_index(0);
return swt;
}
if(ncons == 2){
return Split2(j2split);
}
const double R_max = R_factor*rp;
assert(R_max < M_PI);
double pt_remaining = j2split.pt();
const double phi_jet = j2split.phi();
const double y_jet = j2split.rapidity();
for(int i = 0; i < ncons - 1; ++i){
/**
* Generate rapidity and azimuthal angle with a distance
* R = sqrt(delta_y^2 + delta_phi^2) < R_max
* from the jet centre
*/
const double R = R_max*ran.flat();
const double theta = 2*M_PI*ran.flat();
const double delta_phi = R*cos(theta);
const double delta_y = R*sin(theta);
/**
* Generate pt such that the total contribution of all partons
* along the jet pt axis does not exceed the jet pt
*/
const double pt_max = pt_remaining/cos(delta_phi);
assert(pt_max > 0);
if(pt_max < ccut) return false; // no pt remaining for this parton
const double pt = (pt_max - ccut)*ran.flat() + ccut;
pt_remaining -= pt*cos(delta_phi);
jcons.emplace_back(
pt*cos(phi_jet + delta_phi), pt*sin(phi_jet + delta_phi),
pt*sinh(y_jet + delta_y), pt*cosh(y_jet + delta_y)
);
jcons.back().set_user_index(i);
swt *= 2*M_PI*R*R_max*pt*(pt_max - ccut);
}
const fastjet::PseudoJet p_total = std::accumulate(
jcons.begin(), jcons.end(), fastjet::PseudoJet{}
);
// Calculate the pt of the last parton
const double last_px = j2split.px() - p_total.px();
const double last_py = j2split.py() - p_total.py();
const double last_pt = sqrt(last_px*last_px + last_py*last_py);
if(last_pt < ccut) return 0.;
// Calculate the rapidity of the last parton using the requirement that the
// new jet must have the same rapidity as the LO jet.
const double exp_2y_jet = (j2split.e() + j2split.pz())/(j2split.e() - j2split.pz());
const double bb = (p_total.e()+p_total.pz()) - exp_2y_jet*(p_total.e()-p_total.pz());
const double lasty = log((-bb+sqrt(bb*bb+4.*exp_2y_jet*last_pt*last_pt))/(2.*last_pt));
jcons.emplace_back(
last_px, last_py, last_pt*sinh(lasty), last_pt*cosh(lasty)
);
jcons.back().set_user_index(ncons-1);
assert(same_pt_and_rapidity(begin(jcons), end(jcons), j2split));
// Test that the last parton is not too far away from the jet centre.
if (jcons.back().delta_R(j2split) > R_max) return 0.;
if(! all_in_one_jet(jcons, jet_def, jetptmin)) return 0.;
return swt;
}
//! sample y-phi distance to jet pt axis for a jet splitting into two partons
/**
* @param wt Multiplied by the weight of the sampling point
* @returns The distance in units of the jet radius
*/
double HejSplit::sample_distance_2p(double & wt){
static constexpr double x_small = 0.1;
static constexpr double p_small = 0.4;
const double pR = ran.flat();
if(pR < p_small){
wt *= x_small/p_small;
return x_small/p_small*pR;
}
wt *= (1-x_small)/(1-p_small);
return (1-x_small)/(1-p_small)*(pR-p_small) + x_small;
}
// split jet into two partons
double HejSplit::Split2(fastjet::PseudoJet const & j2split){
static constexpr size_t ncons = 2;
jcons.resize(ncons);
std::array<double, ncons> R, phi, y, pt;
double wt = 1;
const double theta = 2*M_PI*ran.flat(); // angle in y-phi plane
// empiric observation: we are always within the jet radius
R[0] = sample_distance_2p(wt)*rp;
R[1] = -sample_distance_2p(wt)*rp;
for(size_t i = 0; i <= 1; ++i){
phi[i] = j2split.phi() + R[i]*cos(theta);
y[i] = j2split.rapidity() + R[i]*sin(theta);
}
for(size_t i = 0; i <= 1; ++i){
pt[i] = (j2split.py() - tan(phi[1-i])*j2split.px())/
(sin(phi[i]) - tan(phi[1-i])*cos(phi[i]));
if(pt[i] < ccut) return 0.;
jcons[i].reset_PtYPhiM(pt[i], y[i], phi[i]);
jcons[i].set_user_index(i);
}
assert(same_pt_and_rapidity(begin(jcons), end(jcons), j2split));
if(! all_in_one_jet(jcons, jet_def, jetptmin)) return 0.;
wt *= 2*M_PI*pt[0]*R[0]*rp*rp;
// from transformation of delta(R[1] - ...) to delta(pt[0] - ...)
const double dphi0 = phi[0] - j2split.phi();
const double ptJ = j2split.pt();
const double jacobian = cos(theta)*pt[1]*pt[1]/(ptJ*sin(dphi0));
return jacobian*wt;
}
void HejSplit::PrintConstituentInfo(std::vector<fastjet::PseudoJet> jets){
// tell the user what was done
// - the description of the algorithm used
// - extract the inclusive jets with pt > 5 GeV
// show the output as
// {index, rap, phi, pt, number of constituents}
//----------------------------------------------------------
std::cout << "Ran " << (jet_def).description() << std::endl << std::endl;
// label the columns
printf("%5s %15s %15s %15s %15s\n","jet #", "rapidity", "phi", "pt", "n constituents");
printf(" indices of constituents\n\n");
//njj[jets.size()] += 1;
// print out the details for each jet
for (unsigned int i = 0; i < jets.size(); i++) {
// get the constituents of the jet
std::vector<fastjet::PseudoJet> constituents = jets[i].constituents();
//nco[jets.size()] += int(constituents.size());
//if (int(constituents.size())>maxco)
//maxco = int(constituents.size());
printf("%5u %15.8f %15.8f %15.8f %8u\n",
i, jets[i].rap(), jets[i].phi(),
jets[i].perp(), (unsigned int) constituents.size());
printf(" ");
for (unsigned int j=0; j<constituents.size(); j++){
printf("%4u ", constituents[j].user_index());
if (j%10==9) printf("\n ");
}
printf("\n\n");
}
}

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