gen/lA/oleksii_jpsi_impl.hh

0001 // lAger: General Purpose l/A-event Generator
0002 // Copyright (C) 2016-2021 Sylvester Joosten <sjoosten@anl.gov>
0003 //
0004 // This file is part of lAger.
0005 //
0006 // lAger is free software: you can redistribute it and/or modify
0007 // it under the terms of the GNU General Public License as published by
0008 // the Free Shoftware Foundation, either version 3 of the License, or
0009 // (at your option) any later version.
0010 //
0011 // lAger is distributed in the hope that it will be useful,
0012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
0013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0014 // GNU General Public License for more details.
0015 //
0016 // You should have received a copy of the GNU General Public License
0017 // along with lAger.  If not, see <https://www.gnu.org/licenses/>.
0018 //
0019
0020 #ifndef OLEKSII_JPSI_IMPL_LOADED
0021 #define OLEKSII_JPSI_IMPL_LOADED
0022
0023 #include <complex>
0024
0025 namespace oleksii_jpsi_impl {
0026
0027 std::complex<double> fT1(const double q2, const double Egamma);
0028
0029 double TT(const double t, const double q2, const double Egamma,
0030           const double thetaCM, const double phiCM);
0031
0032 double Re_jpsi_T(const double q2, const double Egamma, const double T_0 = 0);
0033 double Im_jpsi_T(const double q2, const double Egamma, const double T_0 = 0);
0034 double Re_jpsi_fT(const double q2, const double Egamma, const double t,
0035                   const double T_0 = 0);
0036 double Im_jpsi_fT(const double q2, const double Egamma, const double t,
0037                   const double T_0 = 0);
0038
0039 // calculate the cross section
0040 // t: mandelstam t
0041 // q2: invariant mass of dilepton pair squared
0042 // Egamma: photon energy
0043 // thetaCM: electron theta in dilepton CM frame
0044 // phiCM: electron phi in dilepton CM frame
0045 double calc_xsec(const double t, const double q2, const double Egamma,
0046                  const double thetaCM, const double phiCM,
0047                  const double T_0 = 0);
0048 } // namespace oleksii_jpsi_impl
0049
0050 #endif