List of physical constants useful that may be used for the matrix element definition.

Variables
constexpr double	ALPHA_EM = 1. / 137.035999
	Electromagnetic coupling constant \(\alpha_{\rm em}=\frac{e^2}{4\pi\epsilon_0\hbar c}\).

constexpr double	G_EM_SQ = 4. * M_PI * ALPHA_EM
	Electromagnetic charge (~0.303 in natural units)

constexpr double	ALPHA_QCD = 0.1184
	Strong coupling constant \(\alpha_{\rm QCD}\).

constexpr double	GEVM2_TO_PB = 0.389351824e9
	Conversion factor between GeV \(^{-2}\) and barn i.e. \(\hbar^2 c^2\) in GeV \(^{-2}\).

constexpr double	GEVM1_TO_M = 0.1973269804e-15
	Conversion factor between GeV \(^{-1}\) and metres i.e. \(\hbar c\) in GeV \(^{-1}\).

constexpr double	G_F = 1.1663787e-5
	Fermi coupling constant, in GeV \(^{-2}\).

Variable Documentation

◆ ALPHA_EM

constexpr double ALPHA_EM = 1. / 137.035999

constexpr

Definition at line 28 of file Constants.h.

constexpr double ALPHA_QCD = 0.1184

constexpr

Definition at line 34 of file Constants.h.

constexpr double G_EM_SQ = 4. * M_PI * ALPHA_EM

constexpr

Definition at line 31 of file Constants.h.

constexpr double G_F = 1.1663787e-5

constexpr

Definition at line 42 of file Constants.h.

constexpr double GEVM1_TO_M = 0.1973269804e-15

constexpr

Definition at line 40 of file Constants.h.

constexpr double GEVM2_TO_PB = 0.389351824e9

constexpr

Definition at line 37 of file Constants.h.