CLHEP/Units/PhysicalConstants.h

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00001 // -*- C++ -*-
00002 // $Id: PhysicalConstants.h,v 1.5 2002/03/30 15:02:06 evc Exp $
00003 // ----------------------------------------------------------------------
00004 // HEP coherent Physical Constants
00005 //
00006 // This file has been provided by Geant4 (simulation toolkit for HEP).
00007 //
00008 // The basic units are :
00009 //              millimeter  
00010 //              nanosecond  
00011 //              Mega electron Volt  
00012 //              positon charge 
00013 //              degree Kelvin
00014 //              amount of substance (mole)
00015 //              luminous intensity (candela)
00016 //              radian  
00017 //              steradian 
00018 //
00019 // Below is a non exhaustive list of Physical CONSTANTS,
00020 // computed in the Internal HEP System Of Units.
00021 //
00022 // Most of them are extracted from the Particle Data Book :
00023 //        Phys. Rev. D  volume 50 3-1 (1994) page 1233
00024 // 
00025 //        ...with a meaningful (?) name ...
00026 //
00027 // You can add your own constants.
00028 //
00029 // Author: M.Maire
00030 //
00031 // History:
00032 //
00033 // 23.02.96 Created
00034 // 26.03.96 Added constants for standard conditions of temperature
00035 //          and pressure; also added Gas threshold.
00036 
00037 #ifndef HEP_PHYSICAL_CONSTANTS_H
00038 #define HEP_PHYSICAL_CONSTANTS_H
00039 
00040 #include "CLHEP/Units/SystemOfUnits.h"
00041 
00042 //
00043 //
00044 //
00045 static const double     pi  = 3.14159265358979323846;
00046 static const double  twopi  = 2*pi;
00047 static const double halfpi  = pi/2;
00048 static const double     pi2 = pi*pi;
00049 
00050 //
00051 // 
00052 //
00053 static const double Avogadro = 6.0221367e+23/mole;
00054 
00055 //
00056 // c   = 299.792458 mm/ns
00057 // c^2 = 898.7404 (mm/ns)^2 
00058 //
00059 static const double c_light   = 2.99792458e+8 * m/s;
00060 static const double c_squared = c_light * c_light;
00061 
00062 //
00063 // h     = 4.13566e-12 MeV*ns
00064 // hbar  = 6.58212e-13 MeV*ns
00065 // hbarc = 197.32705e-12 MeV*mm
00066 //
00067 static const double h_Planck      = 6.6260755e-34 * joule*s;
00068 static const double hbar_Planck   = h_Planck/twopi;
00069 static const double hbarc         = hbar_Planck * c_light;
00070 static const double hbarc_squared = hbarc * hbarc;
00071 
00072 //
00073 //
00074 //
00075 static const double electron_charge = - eplus; // see SystemOfUnits.h
00076 static const double e_squared = eplus * eplus;
00077 
00078 //
00079 // amu_c2 - atomic equivalent mass unit
00080 // amu    - atomic mass unit
00081 //
00082 static const double electron_mass_c2 = 0.51099906 * MeV;
00083 static const double   proton_mass_c2 = 938.27231 * MeV;
00084 static const double  neutron_mass_c2 = 939.56563 * MeV;
00085 static const double           amu_c2 = 931.49432 * MeV;
00086 static const double              amu = amu_c2/c_squared;
00087 
00088 //
00089 // permeability of free space mu0    = 2.01334e-16 Mev*(ns*eplus)^2/mm
00090 // permittivity of free space epsil0 = 5.52636e+10 eplus^2/(MeV*mm)
00091 //
00092 static const double mu0      = 4*pi*1.e-7 * henry/m;
00093 static const double epsilon0 = 1./(c_squared*mu0);
00094 
00095 //
00096 // electromagnetic coupling = 1.43996e-12 MeV*mm/(eplus^2)
00097 //
00098 static const double elm_coupling           = e_squared/(4*pi*epsilon0);
00099 static const double fine_structure_const   = elm_coupling/hbarc;
00100 static const double classic_electr_radius  = elm_coupling/electron_mass_c2;
00101 static const double electron_Compton_length = hbarc/electron_mass_c2;
00102 static const double Bohr_radius = electron_Compton_length/fine_structure_const;
00103 
00104 static const double alpha_rcl2 = fine_structure_const
00105                                    *classic_electr_radius
00106                                    *classic_electr_radius;
00107 
00108 static const double twopi_mc2_rcl2 = twopi*electron_mass_c2
00109                                              *classic_electr_radius
00110                                              *classic_electr_radius;
00111 //
00112 //
00113 //
00114 static const double k_Boltzmann = 8.617385e-11 * MeV/kelvin;
00115 
00116 //
00117 //
00118 //
00119 static const double STP_Temperature = 273.15*kelvin;
00120 static const double STP_Pressure    = 1.*atmosphere;
00121 static const double kGasThreshold   = 10.*mg/cm3;
00122 
00123 //
00124 //
00125 //
00126 static const double universe_mean_density = 1.e-25*g/cm3;
00127 
00128 #endif /* HEP_PHYSICAL_CONSTANTS_H */
00129 
00130 
00131 
00132 
00133 

Class Library for High Energy Physics (version 1.8)