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/********************************************************************************
Copyright 2013 Jan Kašpar
This file is part of Elegent (http://elegent.hepforge.org/).
Elegent is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Elegent is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Elegent. If not, see <http://www.gnu.org/licenses/>.
********************************************************************************/
#include "interface/FerreiraModel.h"
#include "interface/Constants.h"
#include "interface/Math.h"
using namespace std;
using namespace Elegent;
//----------------------------------------------------------------------------------------------------
FerreiraModel::FerreiraModel()
{
fullLabel.name = "Ferreira"; shortLabel.name = "ferreira";
integ_workspace_initialized = false;
}
//----------------------------------------------------------------------------------------------------
FerreiraModel::~FerreiraModel()
{
if (integ_workspace_initialized)
gsl_integration_workspace_free(integ_workspace_t);
}
//----------------------------------------------------------------------------------------------------
void FerreiraModel::Configure()
{
fullLabel.variant = "";
fullLabel.version = "arXiv:1408.1599v1";
fullLabel.mode = "";
shortLabel.variant = "";
shortLabel.version = "14";
shortLabel.mode = "";
}
//----------------------------------------------------------------------------------------------------
void FerreiraModel::Init()
{
// page 2 in [1]
a0 = 1.39; // GeV^-2
double W = cnts->sqrt_s / 1E3; // sqrt(s) in TeV
double L = log(W / 30.4469);
// Eq. (28) to (35) in [1]
al_i = 11.0935 + 1.35479 * log(W);
al_r = 0.208528 + 0.0419028 * log(W);
be_i = 4.44606586 + 0.3208411 * L + 0.0613381 * sqrt(0.5 + L*L);
be_r = 1.1506 + 0.12584 * log(W) + 0.017002 * log(W) * log(W);
ga_i = 10.025 + 0.79097 * log(W) + 0.088 * log(W) * log(W);
ga_r = 10.401 + 1.4408 * log(W) + 0.16659 * log(W) * log(W);
la_i = 14.02008 + 3.23842 * log(W) + 0.444594 * log(W) * log(W);
la_r = 3.31949 + 0.743706 * log(W);
N = sqrt(cnts->s * cnts->p_cms * cnts->p_cms / cnts->pi);
// integration parameters
precision_t = 1E-4;
upper_bound_t = -50.;
if (!integ_workspace_initialized)
{
integ_workspace_size_t = 100;
integ_workspace_t = gsl_integration_workspace_alloc(integ_workspace_size_t);
integ_workspace_initialized = true;
}
}
//----------------------------------------------------------------------------------------------------
void FerreiraModel::Print() const
{
printf(">> FerreiraModel::Print\n");
printf("\t%s\n", CompileFullLabel().c_str());
printf("\ta0 = %E GeV^-2\n", a0);
printf("\tal_i = %E, al_r = %E\n", al_i, al_r);
printf("\tbe_i = %E, be_r = %E\n", be_i, be_r);
printf("\tga_i = %E, ga_r = %E\n", ga_i, ga_r);
printf("\tla_i = %E, la_r = %E\n", la_i, la_r);
}
//----------------------------------------------------------------------------------------------------
double FerreiraModel::Psi(double ga, double t) const
{
double mt = -t;
double s1 = sqrt(1. + a0 * mt);
double s4 = sqrt(4. + a0 * mt);
return 2. * exp(ga) * (exp(-ga*s1)/s1 - exp(ga) * exp(-ga*s4)/s4);
}
//----------------------------------------------------------------------------------------------------
double FerreiraModel::R_ggg(double t) const
{
if (fabs(t) < 1E-10)
return 0.;
double t2 = t * t;
double t4 = t2 * t2;
double r = 0.45/t4 * (1. - exp(-0.005*t4)) * (1. - exp(-0.1*t2));
return (cnts->pMode == Constants::mPP) ? +r : -r;
}
//----------------------------------------------------------------------------------------------------
TComplex FerreiraModel::Amp(double t) const
{
double mt = -t;
// Eq. (18) in [1]
double re = al_r * exp(-be_r * mt) + la_r * Psi(ga_r, t);
double im = al_i * exp(-be_i * mt) + la_i * Psi(ga_i, t);
// Eq. (21) in [1]
re += R_ggg(t);
return N * TComplex(re, im);
}
//----------------------------------------------------------------------------------------------------
TComplex FerreiraModel::Amp_J0(double t, double *par, const void *vobj)
{
const FerreiraModel *obj = (FerreiraModel *) vobj;
const double &b = par[0]; // impact parameter in GeV^-1
return obj->Amp(t) * TMath::BesselJ0(b * sqrt(-t));
}
//----------------------------------------------------------------------------------------------------
TComplex FerreiraModel::Prf(double b_fm) const
{
double b = b_fm / cnts->hbarc; // b in GeV^-1
double par[] = { b };
TComplex I = ComplexIntegrate(Amp_J0, par, this, upper_bound_t, 0., 0., precision_t,
integ_workspace_size_t, integ_workspace_t, "FerreiraModel::Prf");
return I / 4. / cnts->p_cms / cnts->sqrt_s;
}

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