Probing chirality structure in lepton-flavour-violating Higgs decay $h\to \tau \mu$ at the LHC

Abstract

A phenomenological study for determining the chirality structure in lepton-flavor-violating Higgs (hLFV) decays $h\to \tau \mu$ at the LHC is presented. We estimate the effects of the $\tau$ polarization in the analysis andthe importance of determining the relative visible momentum ratio $x$, and show the analysis with a collinear mass $m_{col1}$ by assuming one missing particle is appropriate. We find that the sensitivity would be generically affected up to $\pm$ $4-6$~\% in terms of the BR$(h\to \tau \mu )$ upper bound, and show the altered bounds on the $(|y_{\mu \tau }|,|y_{\tau \mu }|)$ plane. We further study the benchmark scenarios, and demonstrate the sensitivity study for the chirality structure using the relative visible momentum ratio. We find that the two fully polarized cases, the ${\tau }_R$ and ${\tau }_L$ scenarios consistent with the recently reported excess, are distinguishable at 2$\sigma$ level for 1000~fb${}^{-1}$. We also show that a further improved study potentially provides a similar sensitivity already for 139~fb${}^{-1}$.

Comments: Published in Phys. Rev. D 107, 055037, 27 pages, 8 figures and 5 tables