Search for lepton flavour violating decays of a neutral heavy Higgs boson to $\mu\tau$ and e$\tau$ in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports a search for lepton flavor violating decays of a heavy neutral Higgs boson into mu-tau and e-tau modes using 13 TeV proton-proton collision data, setting upper limits on production cross sections.

Contribution

First search for these specific lepton flavor violating Higgs decays at 13 TeV, providing new constraints on non-standard Higgs boson models.

Findings

No signal observed in the 200-900 GeV mass range.

Upper limits on production cross section times branching ratio range from 1.6 to 51.9 fb.

Results improve constraints on lepton flavor violation in Higgs sector.

Abstract

A search for lepton flavour violating decays of a neutral non-standard-model Higgs boson in the $\mu\tau$ and e$\tau$ decay modes is presented. The search is based on proton-proton collisions at a center of mass energy $\sqrt{s} =$ 13 TeV collected with the CMS detector in 2016, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The $\tau$ leptons are reconstructed in the leptonic and hadronic decay modes. No signal is observed in the mass range 200-900 GeV. At 95% confidence level, the observed (expected) upper limits on the production cross section multiplied by the branching fraction vary from 51.9 (57.4) fb to 1.6 (2.1) fb for the $\mu\tau$ and from 94.1 (91.6) fb to 2.3 (2.3) fb for the e$\tau$ decay modes.