particledata.cc

Go to the documentation of this file.

/*
 *
 *    Copyright (c) 2014-2020
 *      SMASH Team
 *
 *    GNU General Public License (GPLv3 or later)
 *
 */
 
#include "smash/particledata.h"
 
#include <iomanip>
#include <iostream>
#include <vector>
 
#include "smash/constants.h"
#include "smash/iomanipulators.h"
 
namespace smash {
 
double ParticleData::effective_mass() const {
  const double m_pole = pole_mass();
  if (m_pole < really_small) {
    // prevent numerical problems with massless or very light particles
    return m_pole;
  } else {
    return momentum().abs();
  }
}
 
void ParticleData::set_history(int ncoll, uint32_t pid, ProcessType pt,
                               double time_last_coll,
                               const ParticleList &plist) {
  if (pt != ProcessType::Wall) {
    history_.collisions_per_particle = ncoll;
    history_.time_last_collision = time_last_coll;
  }
  history_.id_process = pid;
  history_.process_type = pt;
  switch (pt) {
    case ProcessType::Decay:
    case ProcessType::Wall:
      // only store one parent
      history_.p1 = plist[0].pdgcode();
      history_.p2 = 0x0;
      break;
    case ProcessType::Elastic:
    case ProcessType::HyperSurfaceCrossing:
    case ProcessType::FailedString:
      // Parent particles are not updated by the elastic scatterings,
      // hypersurface crossings or failed string processes
      break;
    case ProcessType::TwoToOne:
    case ProcessType::TwoToTwo:
    case ProcessType::TwoToThree:
    case ProcessType::StringSoftSingleDiffractiveAX:
    case ProcessType::StringSoftSingleDiffractiveXB:
    case ProcessType::StringSoftDoubleDiffractive:
    case ProcessType::StringSoftAnnihilation:
    case ProcessType::StringSoftNonDiffractive:
    case ProcessType::StringHard:
    case ProcessType::Bremsstrahlung:
      // store two parent particles
      history_.p1 = plist[0].pdgcode();
      history_.p2 = plist[1].pdgcode();
      break;
    case ProcessType::Thermalization:
    case ProcessType::MultiParticleThreeMesonsToOne:
    case ProcessType::MultiParticleThreeToTwo:
    case ProcessType::None:
      // nullify parents
      history_.p1 = 0x0;
      history_.p2 = 0x0;
      break;
  }
}
 
double ParticleData::xsec_scaling_factor(double delta_time) const {
  double time_of_interest = position_.x0() + delta_time;
  // cross section scaling factor at the time_of_interest
  double scaling_factor;
 
  if (formation_power_ <= 0.) {
    // use a step function to form particles
    if (time_of_interest < formation_time_) {
      // particles will not be fully formed at time of interest
      scaling_factor = initial_xsec_scaling_factor_;
    } else {
      // particles are fully formed at time of interest
      scaling_factor = 1.;
    }
  } else {
    // use smooth function to scale cross section (unless particles are already
    // fully formed at desired time or will start to form later)
    if (formation_time_ <= time_of_interest) {
      // particles are fully formed when colliding
      scaling_factor = 1.;
    } else if (begin_formation_time_ >= time_of_interest) {
      // particles will start formimg later
      scaling_factor = initial_xsec_scaling_factor_;
    } else {
      // particles are in the process of formation at the given time
      scaling_factor =
          initial_xsec_scaling_factor_ +
          (1. - initial_xsec_scaling_factor_) *
              std::pow((time_of_interest - begin_formation_time_) /
                           (formation_time_ - begin_formation_time_),
                       formation_power_);
    }
  }
  return scaling_factor;
}
 
std::ostream &operator<<(std::ostream &out, const ParticleData &p) {
  out.fill(' ');
  return out << p.type().name() << " (" << std::setw(5) << p.type().pdgcode()
             << ")" << std::right << "{id:" << field<6> << p.id()
             << ", process:" << field<4> << p.id_process()
             << ", pos [fm]:" << p.position() << ", mom [GeV]:" << p.momentum()
             << ", formation time [fm]:" << p.formation_time()
             << ", cross section scaling factor:" << p.xsec_scaling_factor()
             << "}";
}
 
std::ostream &operator<<(std::ostream &out, const ParticleList &particle_list) {
  auto column = out.tellp();
  out << '[';
  for (const auto &p : particle_list) {
    if (out.tellp() - column >= 201) {
      out << '\n';
      column = out.tellp();
      out << ' ';
    }
    out << std::setw(5) << std::setprecision(3) << p.momentum().abs3()
        << p.type().name();
  }
  return out << ']';
}
 
std::ostream &operator<<(std::ostream &out,
                         const PrintParticleListDetailed &particle_list) {
  bool first = true;
  out << '[';
  for (const auto &p : particle_list.list) {
    if (first) {
      first = false;
    } else {
      out << "\n ";
    }
    out << p;
  }
  return out << ']';
}
 
double ParticleData::formation_power_ = 0.0;
 
}  // namespace smash