Version: SMASH-3.1
constants.h
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1 /*
2  * Copyright (c) 2013-2021,2023
3  * SMASH Team
4  *
5  * GNU General Public License (GPLv3 or later)
6  */
7 #ifndef SRC_INCLUDE_SMASH_CONSTANTS_H_
8 #define SRC_INCLUDE_SMASH_CONSTANTS_H_
9 
10 #include <cmath>
11 #include <cstdint>
12 #include <limits>
13 
20 namespace smash {
21 
25 constexpr double hbarc = 0.197327053;
26 
28 constexpr double fm2_mb = 0.1;
29 
31 constexpr double gev2_mb = hbarc * hbarc / fm2_mb;
32 
34 constexpr double mev_to_gev = 1.e-3;
35 
37 constexpr double really_small = 1.0e-6;
38 
40 constexpr double very_small_double = 1.0e-15;
41 
45 constexpr double twopi = 2. * M_PI;
46 
48 constexpr double nuclear_density = 0.168;
49 
51 constexpr double small_number = 1.0e-4;
52 
58 constexpr double nucleon_mass = 0.938;
59 
65 constexpr double pion_mass = 0.138;
66 
72 constexpr double kaon_mass = 0.494;
73 
79 constexpr double omega_mass = 0.783;
80 
86 constexpr double delta_mass = 1.232;
92 constexpr double deuteron_mass = 1.8756;
93 
95 constexpr double fine_structure = 7.2973525698e-3;
96 
98 const double elementary_charge = std::sqrt(fine_structure * 4 * M_PI);
99 
103 constexpr int maximum_rndm_seed_in_pythia = 900000000;
104 
111 constexpr double minimum_sqrts_pythia_can_handle = 10.0; // GeV
112 
118 constexpr std::uint32_t ID_PROCESS_PHOTON =
119  std::numeric_limits<std::uint32_t>::max();
120 
121 } // namespace smash
122 
123 #endif // SRC_INCLUDE_SMASH_CONSTANTS_H_
Definition: action.h:24
constexpr double mev_to_gev
MeV to GeV conversion factor.
Definition: constants.h:34
constexpr double delta_mass
Delta mass in GeV.
Definition: constants.h:86
constexpr double gev2_mb
GeV^-2 <-> mb conversion factor.
Definition: constants.h:31
constexpr int maximum_rndm_seed_in_pythia
The maximum value of the random seed used in PYTHIA.
Definition: constants.h:103
constexpr std::uint32_t ID_PROCESS_PHOTON
Process ID for any photon process.
Definition: constants.h:118
constexpr double minimum_sqrts_pythia_can_handle
Energy in GeV, below which hard reactions via pythia are impossible.
Definition: constants.h:111
constexpr double very_small_double
A very small double, used to avoid division by zero.
Definition: constants.h:40
constexpr double twopi
.
Definition: constants.h:45
constexpr double small_number
Physical error tolerance.
Definition: constants.h:51
constexpr double deuteron_mass
Deuteron mass in GeV.
Definition: constants.h:92
constexpr double nucleon_mass
Nucleon mass in GeV.
Definition: constants.h:58
constexpr double nuclear_density
Ground state density of symmetric nuclear matter [fm^-3].
Definition: constants.h:48
constexpr double pion_mass
Pion mass in GeV.
Definition: constants.h:65
constexpr double hbarc
GeV <-> fm conversion factor.
Definition: constants.h:25
constexpr double really_small
Numerical error tolerance.
Definition: constants.h:37
constexpr double kaon_mass
Kaon mass in GeV.
Definition: constants.h:72
constexpr double fine_structure
Fine-struture constant, approximately 1/137.
Definition: constants.h:95
constexpr double omega_mass
omega mass in GeV.
Definition: constants.h:79
const double elementary_charge
Elementary electric charge in natural units, approximately 0.3.
Definition: constants.h:98
constexpr double fm2_mb
mb <-> fm^2 conversion factor.
Definition: constants.h:28