genie::utils::hadxs Namespace Reference

Simple functions and data for computing hadron interaction xsecs. More...

Namespaces
	berger

Functions
double	InelasticPionNucleonXSec (double Epion, bool isChargedPion=true)
double	TotalPionNucleonXSec (double Epion, bool isChargedPion=true)

Variables
static const int	kInelNDataPoints = 60
static const double	kInelMinLog10P = -0.975
static const double	kIneldLog10P = 0.05
static const double	kInelSig [kInelNDataPoints]
static const int	kTotNDataPoints = 60
static const double	kTotMinLog10P = -0.975
static const double	kTotdLog10P = 0.05
static const double	kTotSig [kTotNDataPoints]

Detailed Description

Simple functions and data for computing hadron interaction xsecs.

Author

Costas Andreopoulos <c.andreopoulos cern.ch> University of Liverpool

Created:

March 11, 2004

License:

Copyright (c) 2003-2024, The GENIE Collaboration For the full text of the license visit http://copyright.genie-mc.org

Function Documentation

double genie::utils::hadxs::InelasticPionNucleonXSec	(	double	Epion,
		bool	isChargedPion = true
	)

Definition at line 20 of file HadXSUtils.cxx.

References kIneldLog10P, kInelMinLog10P, kInelNDataPoints, kInelSig, genie::constants::kPi0Mass, genie::constants::kPionMass, genie::constants::kPionMass2, and genie::units::mb.

Referenced by genie::ReinSehgalCOHPiPXSec::XSec().

{
// Returns the interpolated inelastic pion-nucleon cross section.
// C++ adaptation of Hugh Gallagher's NeuGEN inel() function

  double mpi  = kPionMass;
  double mpi2 = kPionMass2;
  if (!isChargedPion) {
    mpi  = kPi0Mass;
    mpi2 = mpi * mpi;
  }
  double Epion2 = TMath::Power(Epion,2);
  double P      = TMath::Sqrt( TMath::Max(0.,Epion2-mpi2) );

  if(P<=0) return 0;

  double log10P  = TMath::Log10(P);
  int    N = (int) ((log10P - kInelMinLog10P)/kIneldLog10P) + 1;

  double xs=0.;
  if ((log10P - kInelMinLog10P) < 0.0) xs = (P/0.1059)*kInelSig[0];
  else if (N>kInelNDataPoints-2) xs = kInelSig[kInelNDataPoints-1];
  else {
   double log10Pn = kInelMinLog10P +  (N-1) * kIneldLog10P;
   double delta   = (kInelSig[N]-kInelSig[N-1])/kIneldLog10P;
   xs = kInelSig[N-1] + delta * (log10P-log10Pn);
  }
  return (xs * units::mb);
}

double genie::utils::hadxs::TotalPionNucleonXSec	(	double	Epion,
		bool	isChargedPion = true
	)

Definition at line 51 of file HadXSUtils.cxx.

References kIneldLog10P, kInelMinLog10P, kInelNDataPoints, genie::constants::kPi0Mass, genie::constants::kPionMass, genie::constants::kPionMass2, kTotdLog10P, kTotMinLog10P, kTotSig, and genie::units::mb.

Referenced by genie::ReinDFRPXSec::XSec(), and genie::ReinSehgalCOHPiPXSec::XSec().

{
// Returns the interpolated total pion-nucleon cross section.
// C++ adaptation of Hugh Gallagher's NeuGEN total() function.

  double mpi  = kPionMass;
  double mpi2 = kPionMass2;
  if (!isChargedPion) {
    mpi  = kPi0Mass;
    mpi2 = mpi * mpi;
  }
  double Epion2 = TMath::Power(Epion,2);
  double P      = TMath::Sqrt( TMath::Max(0.,Epion2-mpi2) );

  if(P<=0) return 0;

  double log10P  = TMath::Log10(P);
  int    N = (int) ((log10P - kInelMinLog10P)/kIneldLog10P) + 1;

  double xs=0.;
  if ((log10P - kInelMinLog10P) < 0.0) xs = (P/0.1059)*kTotSig[0];
  else if (N>kInelNDataPoints-2) xs = kTotSig[kInelNDataPoints-1];
  else {
   double log10Pn = kTotMinLog10P +  (N-1) * kTotdLog10P;
   double delta   = (kTotSig[N]-kTotSig[N-1])/kTotdLog10P;
   xs = kTotSig[N-1] + delta * (log10P-log10Pn);
  }
  return (xs * units::mb);
}

Variable Documentation

const double genie::utils::hadxs::kIneldLog10P = 0.05

static

Definition at line 35 of file HadXSUtils.h.

Referenced by InelasticPionNucleonXSec(), and TotalPionNucleonXSec().

const double genie::utils::hadxs::kInelMinLog10P = -0.975

static

Definition at line 34 of file HadXSUtils.h.

Referenced by InelasticPionNucleonXSec(), and TotalPionNucleonXSec().

const int genie::utils::hadxs::kInelNDataPoints = 60

static

Definition at line 33 of file HadXSUtils.h.

Referenced by InelasticPionNucleonXSec(), and TotalPionNucleonXSec().

const double genie::utils::hadxs::kInelSig[kInelNDataPoints]

static

Initial value:

= {
         1.596,   3.192,   5.692,   5.596,   3.788,   6.528,
        22.931,  43.462,  55.580,  36.761,  19.754,  12.588,
        12.914,  12.500,  13.707,  15.082,  19.671,  16.860,
        21.708,  29.128,  21.752,  22.444,  23.698,  23.847,
        23.067,  25.336,  25.366,  25.273,  24.646,  24.003,
        23.636,  23.615,  23.029,  22.667,  22.434,  21.901,
        21.763,  22.235,  20.177,  21.707,  20.827,  21.102,
        21.028,  21.155,  20.932,  20.577,  20.865,  21.122,
        21.193,  21.081,  20.611,  20.788,  20.591,  20.514,
        20.796,  20.813,  20.425,  20.460,  20.495,  20.530
  }

Definition at line 36 of file HadXSUtils.h.

Referenced by InelasticPionNucleonXSec().

const double genie::utils::hadxs::kTotdLog10P = 0.05

static

Definition at line 53 of file HadXSUtils.h.

Referenced by TotalPionNucleonXSec().

const double genie::utils::hadxs::kTotMinLog10P = -0.975

static

Definition at line 52 of file HadXSUtils.h.

Referenced by TotalPionNucleonXSec().

const int genie::utils::hadxs::kTotNDataPoints = 60

static

Definition at line 51 of file HadXSUtils.h.

const double genie::utils::hadxs::kTotSig[kTotNDataPoints]

static

Initial value:

= {
         3.252,   6.504,  12.316,  18.314,  22.600,  31.435,
        53.933,  84.872, 102.626,  87.084,  60.234,  39.922,
        32.804,  28.935,  27.952,  29.439,  36.824,  31.814,
        35.152,  50.062,  39.079,  35.741,  37.390,  35.575,
        34.043,  34.363,  34.171,  32.990,  32.110,  31.316,
        30.621,  29.918,  29.134,  28.461,  27.985,  27.208,
        26.749,  27.111,  25.047,  26.357,  25.393,  25.777,
        25.467,  25.305,  25.008,  24.814,  24.662,  24.481,
        24.453,  24.336,  24.099,  24.098,  24.010,  23.908,
        23.992,  24.058,  23.805,  23.808,  23.811,  23.815
  }

Definition at line 54 of file HadXSUtils.h.

Referenced by TotalPionNucleonXSec().