39 #ifndef HEP_PHYSICAL_CONSTANTS_H
40 #define HEP_PHYSICAL_CONSTANTS_H
42 #include "CLHEP/Units/defs.h"
43 #include "CLHEP/Units/SystemOfUnits.h"
50 static const double pi = 3.14159265358979323846;
51 static const double twopi = 2*pi;
52 static const double halfpi = pi/2;
53 static const double pi2 = pi*pi;
58 static const double Avogadro = 6.02214179e+23/mole;
64 static const double c_light = 2.99792458e+8 *
m/s;
65 static const double c_squared = c_light * c_light;
72 static const double h_Planck = 6.62606896e-34 * joule*s;
73 static const double hbar_Planck = h_Planck/twopi;
74 static const double hbarc = hbar_Planck * c_light;
75 static const double hbarc_squared = hbarc * hbarc;
80 static const double electron_charge = - eplus;
81 static const double e_squared = eplus * eplus;
88 static const double electron_mass_c2 = 0.510998910 * MeV;
89 static const double proton_mass_c2 = 938.272013 * MeV;
90 static const double neutron_mass_c2 = 939.56536 * MeV;
91 static const double amu_c2 = 931.494028 * MeV;
92 static const double amu = amu_c2/c_squared;
98 static const double mu0 = 4*pi*1.e-7 * henry/
m;
99 static const double epsilon0 = 1./(c_squared*mu0);
104 static const double elm_coupling = e_squared/(4*pi*epsilon0);
105 static const double fine_structure_const = elm_coupling/hbarc;
106 static const double classic_electr_radius = elm_coupling/electron_mass_c2;
107 static const double electron_Compton_length = hbarc/electron_mass_c2;
108 static const double Bohr_radius = electron_Compton_length/fine_structure_const;
110 static const double alpha_rcl2 = fine_structure_const
111 *classic_electr_radius
112 *classic_electr_radius;
114 static const double twopi_mc2_rcl2 = twopi*electron_mass_c2
115 *classic_electr_radius
116 *classic_electr_radius;
120 static const double k_Boltzmann = 8.617343e-11 * MeV/kelvin;
125 static const double STP_Temperature = 273.15*kelvin;
126 static const double STP_Pressure = 1.*atmosphere;
127 static const double kGasThreshold = 10.*mg/cm3;
132 static const double universe_mean_density = 1.e-25*
g/cm3;
136 #ifdef ENABLE_BACKWARDS_COMPATIBILITY
138 using namespace CLHEP;