i'm reading through halzen and martin's chapter 12 on the weak interaction which they calculate the fermi coupling constant form oxygen beta decay using(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\Gamma = 1/\tau = G^2E_0^5/30\pi^3[/itex]

with [itex]E_0 = 1.81[/itex]MeV and [itex]\tau log 2 = 71[/itex] sec. they get [itex]G\approx 10^{-5}/m^2_N[/itex]. where m_N is the nucleon mass.

i cant reproduce this number, just plugging in is way off. are there factors of c or h that i need to include?

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# Fermi coupling constant

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