CP asymmetry in τ → Kπντ within non-minimal SU(5)

Abstract

Direct CP asymmetry in semi-leptonic τ decays is an intriguing hint for new physics beyond the standard model. We investigate the CP asymmetry in {tau}^{-}to {K}_S^0{pi}^{-}{nu}_{tau } and τ− → K−π0ντ decays in the context of the non-minimal SU(5) model, with 45-dimensional Higgs multiplet. We show that the associate color-triplet scalar, which is a natural example of a scalar leptoquark, can mediate the tau to soverline{u}{nu}_{tau } transition and account for the observed 2.8 σ discrepancy in {A}_{textrm{CP}}left({tau}^{-}to {K}_S^0{pi}^{-}{nu}_{tau}right) compared to the SM expectation. We also predict a sizable ACP(τ− → K−π0ντ), of mathcal{O} (10−3), which can be experimentally accessible in current and near future experiments.