chigen::models::chi_2 Class Reference

#include <ColorSingletModels.h>

Inheritance diagram for chigen::models::chi_2:

Public Member Functions
	chi_2 ()
	chi_2 (double ecm)
virtual double	dsdt ()
	ClassDef (chi_2, 1)
virtual void	setSigma ()
virtual bool	setKin ()
bool	setTrialKin ()
	ClassDef (ColorSingletPartonicModel, 1)
	ClassDef (PartonicModel, 1)
virtual bool	next ()

Public Attributes
double	__S__
double	R20
double	alpS
double	Xmin
double	Xmax
double	Pfct
double	PhSp
double	sH2
double	tH2
double	uH2
double	eCM
int	pdgId
EvtSpinDensity	spinDensity
EvtId	evtId
double	mesonMass
double	mesonMass2
double	x1
double	x2
double	sH
double	tH
double	uH
double	sigma
double	MaxSigma
double	MaxSigmaBackup
int	nCall

Detailed Description

Definition at line 206 of file ColorSingletModels.h.

Constructor & Destructor Documentation

chigen::models::chi_2::chi_2 ( )

inline

Definition at line 209 of file ColorSingletModels.h.

                    :
            ColorSingletPartonicModel(
            CHI2_MASS, CHI2_PDG_ID, chigen::evtgen::chi_c2_evt_id,
            createSpinDensity(2, -1), CHI2_MASS, R20_CHI, 3.65e-06) {
            }

chigen::models::chi_2::chi_2 ( double  ecm )

inline

Definition at line 215 of file ColorSingletModels.h.

                              :
            ColorSingletPartonicModel(
            ecm, CHI2_PDG_ID, chigen::evtgen::chi_c2_evt_id,
            createSpinDensity(2, -1), CHI2_MASS, R20_CHI, 3.65e-06) {
            }

Member Function Documentation

chigen::PartonicModel::ClassDef ( PartonicModel  , 1    )

inherited

chigen::models::ColorSingletPartonicModel::ClassDef ( ColorSingletPartonicModel  , 1    )

inherited

chigen::models::chi_2::ClassDef	(	chi_2	,
		1
	)

virtual double chigen::models::chi_2::dsdt ( )

inlinevirtual

d sigma/ dt

Returns

d sigma/ dt

Reimplemented from chigen::models::ColorSingletPartonicModel.

Definition at line 221 of file ColorSingletModels.h.

                                  {
                return (128 * M_PI * pow3(alpS) * R20 * (6 * pow4(mesonMass2) - 12 * pow3(mesonMass2) * (sH + tH) + sH2 * (sH2 + 2 * sH * tH + 2 * tH2)
                        - 2 * mesonMass2 * sH * (sH2 + 7 * sH * tH + 6 * tH2) + pow2(mesonMass2) * (7 * sH2 + 24 * sH * tH + 12 * tH2))) / (27 * pow3(mesonMass) * pow4(mesonMass2 - sH) * pow3(sH));
            }

bool chigen::PartonicModel::next ( )

virtualinherited

Calculates the partonic cross section

Definition at line 22 of file PartonicModel.cxx.

References __chigen_cout__, i, chigen::random::random_engine, and sigma.

                               {
    nCall = 0;
    // trying 1000 attempts
    for (int i = 0; i < 1000; ++i) {
        ++nCall;
        if (!setKin()) {
            continue;
        };
        setSigma();
        if (sigma > MaxSigma) {
            //todo add proper info
            __chigen_cout__ <<
                    "sigma=" << std::setiosflags(ios::scientific) << sigma <<
                    " > MasSigma=" << std::setiosflags(ios::scientific) << MaxSigma <<
                    " Efct=" << sigma / MaxSigma << endl;
            MaxSigma = sigma;
            continue;
        };
        if (sigma / MaxSigma > chigen::random::random_engine->flat()) return true;

    }
    sigma = -1;
    return false;
}

bool chigen::models::ColorSingletPartonicModel::setKin ( )

virtualinherited

fills kinematic variables

Reimplemented from chigen::PartonicModel.

Definition at line 86 of file ColorSingletModels.cxx.

References exp(), chigen::ChiGenRandomEngine::flat(), log(), chigen::random::random_engine, sqrt(), X, and Y.

                                                   {
    PhSp = 1;

    //double Pfct = -1;
    double Amin = pow(Xmin, -Pfct), Amax = pow(Xmax, -Pfct);
    double X = pow(Amin + chigen::random::random_engine->flat()*(Amax - Amin), -1 / Pfct);
    PhSp *= -1 / Pfct * (Amax - Amin) * pow(X, Pfct + 1);
    sH = X*__S__;



    //    double Xmin = 1.1 * mChi2 / S;
    //    double Xmax=1;
    //    double X = Xmin + (1 - Xmin) * rndm.flat();
    //    PhSp *= (1 - Xmin);

    double Ymax = log(1 / X) / 2;
    double Y = Ymax * (2 * chigen::random::random_engine->flat() - 1);
    PhSp *= 2 * Ymax;

    x1 = sqrt(X) * exp(Y);
    x2 = sqrt(X) * exp(-Y);

    if (x1 * x2 * __S__ < mesonMass2) {
        return false;
    }

    sH = x1 * x2*__S__;

    tH = (mesonMass2 - sH) * chigen::random::random_engine->flat();
    PhSp = PhSp * (sH - mesonMass2);
    uH = mesonMass2 - sH - tH;
    sH2 = pow2(sH);
    tH2 = pow2(tH);
    uH2 = pow2(uH);
    return true;
}

void chigen::models::ColorSingletPartonicModel::setSigma ( )

virtualinherited

calculate f1*f2*dSigma/dT of the hard process for the selected kinematics

Reimplemented from chigen::PartonicModel.

Definition at line 77 of file ColorSingletModels.cxx.

References chigen::pythia::pdf, and sigma.

                                                     {
    // hard cross section
    sigma = dsdt();
    // Multiply by PDF's
    sigma = sigma * chigen::pythia::pdf->xf(1, x1, mesonMass2) * chigen::pythia::pdf->xf(1, x2, mesonMass2) / x1 / x2;
    // Correct on change of integration variables
    sigma = sigma*PhSp;
}

bool chigen::models::ColorSingletPartonicModel::setTrialKin ( )

inherited

Calculates trial kinematics

Definition at line 124 of file ColorSingletModels.cxx.

References exp(), log(), chigen::random::random_engine, sigma, sqrt(), X, xmin, and Y.

                                                        {
    PhSp = 1;

    double xmin = 0.67;
    double X = 1.1 * xmin;
    PhSp *= (1 - xmin);
    double Ymax = log(1 / xmin) / 2;
    double Y = 0;
    PhSp *= 2 * Ymax;


    x1 = sqrt(X) * exp(Y);
    x2 = sqrt(X) * exp(-Y);

    if (x1 * x2 * __S__ < mesonMass2) {
        return false;
    }
    sH = X*__S__;
    tH = (mesonMass2 - sH) * chigen::random::random_engine->flat();
    PhSp = PhSp * (sH - mesonMass2);
    uH = mesonMass2 - sH - tH;

    //    MaxSigma = 100000*setSigma();
    setSigma();
    MaxSigma = 16 * 10000 * sigma;
    MaxSigmaBackup = MaxSigma;
    return true;
}

Member Data Documentation

double chigen::models::ColorSingletPartonicModel::__S__

inherited

Proton mass take into account

Definition at line 61 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::models::ColorSingletPartonicModel::alpS

inherited

Definition at line 63 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::PartonicModel::eCM

inherited

C.m. energy

Definition at line 44 of file PartonicModel.h.

Referenced by chigen::ChiGen::ChiGen(), chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel(), chigen::PartonicModel::PartonicModel(), and chigen::PythiaChiGen::PythiaChiGen().

EvtId chigen::PartonicModel::evtId

inherited

EvtGen id

Definition at line 56 of file PartonicModel.h.

Referenced by chigen::PartonicModel::PartonicModel().

double chigen::PartonicModel::MaxSigma

inherited

Maximal sigma

Definition at line 76 of file PartonicModel.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::PartonicModel::MaxSigmaBackup

inherited

Definition at line 76 of file PartonicModel.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::PartonicModel::mesonMass

inherited

Meson mass and its squared

Definition at line 60 of file PartonicModel.h.

Referenced by chigen::PartonicModel::PartonicModel(), and chigen::PndChiGenExclusive::PndChiGenExclusive().

double chigen::PartonicModel::mesonMass2

inherited

Definition at line 60 of file PartonicModel.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel(), and chigen::PartonicModel::PartonicModel().

int chigen::PartonicModel::nCall

inherited

number of attempts

Definition at line 81 of file PartonicModel.h.

int chigen::PartonicModel::pdgId

inherited

Meson id

Definition at line 48 of file PartonicModel.h.

Referenced by chigen::PartonicModel::PartonicModel().

double chigen::models::ColorSingletPartonicModel::Pfct

inherited

Definition at line 64 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::models::ColorSingletPartonicModel::PhSp

inherited

Definition at line 66 of file ColorSingletModels.h.

double chigen::models::ColorSingletPartonicModel::R20

inherited

Definition at line 62 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::PartonicModel::sH

inherited

Mandelstam variables of the hard process

Definition at line 68 of file PartonicModel.h.

double chigen::models::ColorSingletPartonicModel::sH2

inherited

Definition at line 67 of file ColorSingletModels.h.

double chigen::PartonicModel::sigma

inherited

dsdt

Definition at line 72 of file PartonicModel.h.

EvtSpinDensity chigen::PartonicModel::spinDensity

inherited

Spin density corresponding to this polarization

Definition at line 52 of file PartonicModel.h.

Referenced by chigen::PartonicModel::PartonicModel().

double chigen::PartonicModel::tH

inherited

Definition at line 68 of file PartonicModel.h.

double chigen::models::ColorSingletPartonicModel::tH2

inherited

Definition at line 67 of file ColorSingletModels.h.

double chigen::PartonicModel::uH

inherited

Definition at line 68 of file PartonicModel.h.

double chigen::models::ColorSingletPartonicModel::uH2

inherited

Definition at line 67 of file ColorSingletModels.h.

double chigen::PartonicModel::x1

inherited

Momentum fractions of the incoming partons

Definition at line 64 of file PartonicModel.h.

double chigen::PartonicModel::x2

inherited

Definition at line 64 of file PartonicModel.h.

double chigen::models::ColorSingletPartonicModel::Xmax

inherited

Definition at line 64 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

double chigen::models::ColorSingletPartonicModel::Xmin

inherited

Definition at line 64 of file ColorSingletModels.h.

Referenced by chigen::models::ColorSingletPartonicModel::ColorSingletPartonicModel().

---

The documentation for this class was generated from the following file:

• ColorSingletModels.h