SimpleParticle.h

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/*
 * Thermal-FIST package
 * 
 * Copyright (c) 2014-2019 Volodymyr Vovchenko
 *
 * GNU General Public License (GPLv3 or later)
 */
#ifndef SIMPLEPARTICLE_H
#define SIMPLEPARTICLE_H
 
#include <cmath>
 
namespace thermalfist {
  struct SimpleParticle {
    double px, py, pz;       
    double m;                
    double p0;               
    long long PDGID;         
    long long MotherPDGID;   
    int epoch;               
    bool processed;          
 
    double r0, rx, ry, rz;   

    SimpleParticle(double inPx = 0., double inPy = 0., double inPz = 0., double inM = 0., long long inPDGID = 0., long long inMotherPDGID = 0,
      double inR0 = 0., double inRx = 0., double inRy = 0., double inRz = 0.) :
      px(inPx),
      py(inPy),
      pz(inPz),
      m(inM),
      p0(sqrt(m*m + px * px + py * py + pz * pz)),
      PDGID(inPDGID), MotherPDGID(inMotherPDGID), 
      epoch(0), processed(false),
      r0(inR0), rx(inRx), ry(inRy), rz(inRz)
    { }

    double GetP() const {
      return sqrt(p0*p0 - m * m);
    }

    double GetPt() const {
      return sqrt(px*px + py * py);
    }

    double GetMt() const {
      return sqrt(m*m + px * px + py * py);
    }

    double GetY() const {
      return 0.5*log((p0 + pz) / (p0 - pz));
    }

    double GetEta() const {
      //return atanh(pz/GetP());
      return 0.5*log((GetP() + pz) / (GetP() - pz));
    }

    double GetTau() const {
      return sqrt(r0 * r0 - rz * rz);
    }
    
    double GetEtaS() const {
      return 0.5 * log((r0 + rz) / (r0 - rz));
    }

    void RapidityBoost(double dY) {
      pz = GetMt() * sinh(GetY() + dY);
      p0 = sqrt(m*m + px * px + py * py + pz * pz);
 
      double tau = GetTau();
      double etas = GetEtaS();
      etas += dY;
 
      r0 = tau * cosh(etas);
      rz = tau * sinh(etas);
    }
  };
 
} // namespace thermalfist
 
#endif