Definitions

Physical Constants

Quantity	Symbol	Value
Speed of light in vacuum	$c$	$2.998\times {10}^8$  m s-1
Planck’s constant	$h$	$4.136\times {10}^{-24}$  GeV s
Planck’s constant reduced	$\mathrm{\hslash }\equiv h/2\pi$	$6.582\times {10}^{-25}$ GeV s
	$\mathrm{\hslash }c$	$1.973\times {10}^{-16}$ GeV m
		$197.3$ MeV fm
	${(\mathrm{\hslash }c)}^2$	$3.894\times {10}^{-32}$ GeV2 m2
Electron charge (magnitude)	$e$	$1.602\times {10}^{-19}$ C
Fine structure constant	$\alpha \equiv e^2/4\pi {\epsilon }_0\mathrm{\hslash }c$	$7.297\times {10}^{-3}=1/137.04$
Electron mass	$m_e$	0.511 MeV/$c^2$
Proton mass	$m_p$	1.00728 u
		0.9383 GeV/$c^2$
Neutron mass	$m_n$	1.00866 u
		0.9396 GeV/$c^2$
W boson mass	$M_W$	80.40 GeV/$c^2$
Z boson mass	$M_Z$	91.19 Gev/$c^2$
Fermi coupling constant	$G_F/{(\mathrm{\hslash }c)}^3$	$1.166\times {10}^{-5}$ GeV-2
Other useful quantities	$e^2/4\pi {\epsilon }_0$	$1.440$ MeV fm

Conversion Factors

1 eV	=	$1.602\times {10}^{-19}$ J = 11605 K				1 eV/$c^2$	=	$1.783\times {10}^{-36}$ kg
1 fermi $\equiv$ 1 fm	=	${10}^{-15}$ m				1 barn $\equiv 1$b	=	${10}^{-28}$m2
1 u	=	931.5 MeV/$c^2$

Natural Units When using natural units, where $\mathrm{\hslash }=c=1$ then the following conversion factors can be useful.

Times			1 GeV-1	=	$6.58\times {10}^{-25}$ s
Length			1 GeV-1	=	0.197 fm
Cross-section			1 GeV-2	=	0.389 mb