Lepton flavor violating tau decays in type-III seesaw mechanism

Abstract

In this paper, the lepton flavor violating $\tau \to \ell P(V)$ ($P,V={\pi }^0,\eta ,{\eta }^{\prime },{\rho }^0,\omega ,\varphi$) and $\tau \to 3\ell$ ($\ell =e,\mu$) decays are studied in the framework of the type-III seesaw model, in which new triplet fermions with a zero hypercharge (Y=0) interact with ordinary lepton doublets via Yukawa couplings, and affect tree-level leptonic Z-boson couplings. We investigate the experimental bound from the leptonic Z decay to get contraint on the exsiting parameters space. We predict that the upper limits on the branching ratios of $\tau \to \ell P(V)$ and $\tau \to 3\ell$ can reach the experimental current limits.

Comments: 15 pages, 1 figure, to match version in press in Phys.Rev.D