Lepton flavor violation in tau decays
Citations Over TimeTop 10% of 2002 papers
Abstract
We study lepton flavor violation (LFV) in tau decays induced by heavy Majorana neutrinos within two models: (I) the standard model with additional right-handed heavy Majorana neutrinos, i.e., a typical seesaw-type model; (II) the standard model with left-handed and right-handed neutral singlets, which are inspired by certain scenarios of $\mathrm{SO}(10)$ models and heterotic superstring models with ${E}_{6}$ symmetry. We calculate various LFV branching ratios and a T-odd asymmetry. The seesaw model I predicts very small branching ratios for LFV processes in most of the parameter space, although in a very restricted parameter region it can reach maximal branching ratios $Br(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}\ensuremath{\mu}\ensuremath{\gamma})\ensuremath{\sim}{10}^{\ensuremath{-}9}$ and $Br(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}3\ensuremath{\mu})\ensuremath{\sim}{10}^{\ensuremath{-}10}.$ In contrast, model II may show branching ratios $Br(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}e\ensuremath{\gamma})\ensuremath{\sim}{10}^{\ensuremath{-}8}$ and $Br(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}3e)\ensuremath{\lesssim}{10}^{\ensuremath{-}9}$ over a sizable region of the parameter space, large enough to be tested by experiments in the near future.