Logo ROOT  
Reference Guide
 
Loading...
Searching...
No Matches
TGeoPhysicalConstants.h
Go to the documentation of this file.
1/*************************************************************************
2 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *
3 * All rights reserved. *
4 * *
5 * For the licensing terms see $ROOTSYS/LICENSE. *
6 * For the list of contributors see $ROOTSYS/README/CREDITS. *
7 *************************************************************************/
8
9// ----------------------------------------------------------------------
10// HEP coherent Physical Constants
11// Adapted for ROOT by Marko Petric
12//
13// This file has been provided by Geant4 (simulation toolkit for HEP).
14//
15// Below is a non exhaustive list of Physical CONSTANTS,
16// computed in the Internal HEP System Of Units.
17//
18// Most of them are extracted from the Particle Data Book :
19// Phys. Rev. D volume 50 3-1 (1994) page 1233
20//
21//
22// Author: M.Maire
23//
24// History:
25//
26// 23.02.96 Created
27// 26.03.96 Added constants for standard conditions of temperature
28// and pressure; also added Gas threshold.
29// 29.04.08 use PDG 2006 values
30// 03.11.08 use PDG 2008 values
31// 02.10.17 addopted constant from CLHEP 2.3.4.3
32
33#ifndef TGEO_PHYSICAL_CONSTANTS_H
34#define TGEO_PHYSICAL_CONSTANTS_H
35
36#include "TGeoSystemOfUnits.h"
37
38namespace TGeoUnit {
39
40//
41//
42//
43static constexpr double Avogadro = 6.02214179e+23 / mole;
44
45//
46// c = 299.792458 mm/ns
47// c^2 = 898.7404 (mm/ns)^2
48//
49static constexpr double c_light = 2.99792458e+8 * m / s;
50static constexpr double c_squared = c_light * c_light;
51
52//
53// h = 4.13566e-12 MeV*ns
54// hbar = 6.58212e-13 MeV*ns
55// hbarc = 197.32705e-12 MeV*mm
56//
57static constexpr double h_Planck = 6.62606896e-34 * joule * s;
58static constexpr double hbar_Planck = h_Planck / twopi;
59static constexpr double hbarc = hbar_Planck * c_light;
60static constexpr double hbarc_squared = hbarc * hbarc;
61
62//
63//
64//
65static constexpr double electron_charge = -eplus; // see SystemOfUnits.h
66static constexpr double e_squared = eplus * eplus;
67
68//
69// amu_c2 - atomic equivalent mass unit
70// - AKA, unified atomic mass unit (u)
71// amu - atomic mass unit
72//
73static constexpr double electron_mass_c2 = 0.510998910 * MeV;
74static constexpr double proton_mass_c2 = 938.272013 * MeV;
75static constexpr double neutron_mass_c2 = 939.56536 * MeV;
76static constexpr double amu_c2 = 931.494028 * MeV;
77static constexpr double amu = amu_c2 / c_squared;
78
79//
80// permeability of free space mu0 = 2.01334e-16 Mev*(ns*eplus)^2/mm
81// permittivity of free space epsil0 = 5.52636e+10 eplus^2/(MeV*mm)
82//
83static constexpr double mu0 = 4 * pi * 1.e-7 * henry / m;
84static constexpr double epsilon0 = 1. / (c_squared * mu0);
85
86//
87// electromagnetic coupling = 1.43996e-12 MeV*mm/(eplus^2)
88//
89static constexpr double elm_coupling = e_squared / (4 * pi * epsilon0);
90static constexpr double fine_structure_const = elm_coupling / hbarc;
94
96
98//
99//
100//
101static constexpr double k_Boltzmann = 8.617343e-11 * MeV / kelvin;
102
103//
104//
105//
106static constexpr double STP_Temperature = 273.15 * kelvin;
107static constexpr double STP_Pressure = 1. * atmosphere;
108static constexpr double kGasThreshold = 10. * mg / cm3;
109
110//
111//
112//
113static constexpr double universe_mean_density = 1.e-25 * g / cm3;
114
115} // namespace TGeoUnit
116
117#endif /* TGEO_PHYSICAL_CONSTANTS_H */
static constexpr double mg
static constexpr double electron_mass_c2
static constexpr double amu
static constexpr double atmosphere
static constexpr double cm3
static constexpr double proton_mass_c2
static constexpr double c_light
static constexpr double hbarc
static constexpr double electron_Compton_length
static constexpr double s
static constexpr double eplus
static constexpr double MeV
static constexpr double pi
static constexpr double neutron_mass_c2
static constexpr double amu_c2
static constexpr double hbarc_squared
static constexpr double Bohr_radius
static constexpr double mu0
static constexpr double kGasThreshold
static constexpr double henry
static constexpr double twopi
static constexpr double hbar_Planck
static constexpr double electron_charge
static constexpr double joule
static constexpr double mole
static constexpr double fine_structure_const
static constexpr double alpha_rcl2
static constexpr double m
static constexpr double STP_Temperature
static constexpr double elm_coupling
static constexpr double e_squared
static constexpr double universe_mean_density
static constexpr double k_Boltzmann
static constexpr double classic_electr_radius
static constexpr double twopi_mc2_rcl2
static constexpr double h_Planck
static constexpr double Avogadro
static constexpr double c_squared
static constexpr double epsilon0
static constexpr double kelvin
static constexpr double g
static constexpr double STP_Pressure