Zero-Mass Leptonic Decays ofWBosons

Abstract

The leptonic decays of the intermediate vector bosons with radiative corrections is studied in the limit where the mass of the charged lepton tends to zero. By means of a simple rule of calculation, we show the independence of the problem on the boson spin. Thus the ratio of the decay rates $\frac{(W\ensuremath{\rightarrow}e\ensuremath{\nu})}{(W\ensuremath{\rightarrow}\ensuremath{\mu}{\ensuremath{\nu}}^{\ensuremath{'}})}$ is obtainable from the corresponding ratio for a spin-zero boson interacting with a weak scalar current. While the radiative correction to the ratio of total decay rates is zero in this approximation, the result is also given for the nonzero correction in the case where discrimination against high-bremsstrahlung photon energies is applied. The spin independence is shown to be true for all boson spins (to the lowest order in $\ensuremath{\alpha}$).