Constant

Symbol

Value [cgs]

fine structure constant

$\alpha$

7.2973525693 × 10⁻³

Planck’s constant

h

6.62607015 × 10⁻²⁷

speed of light

c

2.99792458 × 10¹⁰

electron mass

m

9.1093837015 × 10⁻²⁸ = 0.51099895000 MeV

pion mass

${\pi }^{+}$

139.57077 MeV/c2

muon mass

$m_{\mu }$

1.883531627 × 10⁻²⁵ g