Allowed beta-decay momentum spectrum
= Allowed beta-decay momentum spectrum
{title2=$d\Gamma/dp=C F(Z,E)p^2(E_0-E)^2$}
With a momentum-independent allowed nuclear <matrix element>, negligible <nuclear recoil> and negligible <neutrino mass>, the <electron> spectrum in <natural units> is $d\Gamma/dp=C F(Z,E)p^2(E_0-E)^2$, where $E=\sqrt{p^2+m_e^2}$. Transforming to an <energy> spectrum requires the <Jacobian determinant> $dp/dE=E/p$.