Units and Constants

The natural unit system with \(\mathrm{GeV} \equiv 1\) is used inside DarkProp.

Refer to PDG 2020. https://pdg.lbl.gov/2021/reviews/contents_sports.html

namespace darkprop

namespace constants

Variables

constexpr double mp = 938.27208816 * units::MeV

proton mass

constexpr double mn = 939.56542052 * units::MeV

neutron mass

constexpr double me = 0.51099895 * units::MeV

electron mass

constexpr double mu = 931.49410242 * units::MeV

atomic mass unit

constexpr double alpha = 7.29735256931e-3

fine-structure constant

constexpr double alpha2 = alpha * alpha

constexpr double rEarth = 6371.0 * units::km

constexpr double rSun = 69634000000 * units::cm

constexpr double v0 = 220.0 * units::km / units::sec

constexpr double vesc = 544.0 * units::km / units::sec

constexpr double vearth = 240.0 * units::km / units::sec

namespace units

Variables

constexpr double GeV = 1.0

constexpr double eV = 1e-9 * GeV

constexpr double keV = 1e-6 * GeV

constexpr double MeV = 1e-3 * GeV

constexpr double TeV = 1e3 * GeV

constexpr double PeV = 1e6 * GeV

constexpr double fm = 1.0 / (197.3269804 * MeV)

constexpr double mm = 1e12 * fm

constexpr double cm = 10.0 * mm

constexpr double cm2 = cm * cm

constexpr double cm3 = cm2 * cm

constexpr double m = 1e3 * mm

constexpr double km = 1e3 * m

constexpr double au = 149597870700 * m

constexpr double pc = 3.08567758149e16 * m

constexpr double kpc = 1e3 * pc

constexpr double Mpc = 1e6 * pc

constexpr double barn = 1e-24 * cm * cm

constexpr double pb = 1e-36 * cm * cm

constexpr double sec = 299792458 * m

constexpr double minute = 60 * sec

constexpr double hour = 60 * minute

constexpr double day = 24 * hour

constexpr double year = 31556925.1 * sec

tropical year

constexpr double kg = sec / (1.0545718e-34 * m * m)

constexpr double gram = 1e-3 * kg

constexpr double g_cm3 = gram / (cm * cm * cm)

constexpr double N = kg * m / sec / sec

newton

constexpr double J = kg * m * m / sec / sec

joule

constexpr double F = m / 8.8541878128e-12

farad

const double A = std::sqrt(1.00000000055 * 4 * M_PI * 1e-7 * N)

ampere

const double C = A * sec

coulomb

Variables

constexpr double GeV = 1.0

constexpr double eV = 1e-9 * GeV

constexpr double keV = 1e-6 * GeV

constexpr double MeV = 1e-3 * GeV

constexpr double TeV = 1e3 * GeV

constexpr double PeV = 1e6 * GeV

constexpr double fm = 1.0 / (197.3269804 * MeV)

constexpr double mm = 1e12 * fm

constexpr double cm = 10.0 * mm

constexpr double cm2 = cm * cm

constexpr double cm3 = cm2 * cm

constexpr double m = 1e3 * mm

constexpr double km = 1e3 * m

constexpr double au = 149597870700 * m

constexpr double pc = 3.08567758149e16 * m

constexpr double kpc = 1e3 * pc

constexpr double Mpc = 1e6 * pc

constexpr double barn = 1e-24 * cm * cm

constexpr double pb = 1e-36 * cm * cm

constexpr double sec = 299792458 * m

constexpr double minute = 60 * sec

constexpr double hour = 60 * minute

constexpr double day = 24 * hour

constexpr double year = 31556925.1 * sec

tropical year

constexpr double kg = sec / (1.0545718e-34 * m * m)

constexpr double gram = 1e-3 * kg

constexpr double g_cm3 = gram / (cm * cm * cm)

constexpr double N = kg * m / sec / sec

newton

constexpr double J = kg * m * m / sec / sec

joule

constexpr double F = m / 8.8541878128e-12

farad

const double A = std::sqrt(1.00000000055 * 4 * M_PI * 1e-7 * N)

ampere

const double C = A * sec

coulomb

constexpr double mp = 938.27208816 * units::MeV

proton mass

constexpr double mn = 939.56542052 * units::MeV

neutron mass

constexpr double me = 0.51099895 * units::MeV

electron mass

constexpr double mu = 931.49410242 * units::MeV

atomic mass unit

constexpr double alpha = 7.29735256931e-3

fine-structure constant

constexpr double alpha2 = alpha * alpha

constexpr double rEarth = 6371.0 * units::km

constexpr double rSun = 69634000000 * units::cm

constexpr double v0 = 220.0 * units::km / units::sec

constexpr double vesc = 544.0 * units::km / units::sec

constexpr double vearth = 240.0 * units::km / units::sec