Search for supersymmetry in events with a $\tau$ lepton pair and missing transverse momentum in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports a search for supersymmetric particles in proton-proton collisions at 13 TeV, focusing on events with tau lepton pairs and missing transverse momentum, setting new limits on particle masses.

Contribution

It presents the first search for electroweak supersymmetry involving tau leptons at 13 TeV with CMS, providing new exclusion limits on tau slepton, chargino, and neutralino masses.

Findings

No excess over standard model background observed.

Sets upper limits on tau slepton pair production cross section.

Excludes tau slepton masses up to 710 GeV in certain models.

Abstract

A search for the electroweak production of supersymmetric particles in proton-proton collisions at a center-of-mass energy of 13 TeV is presented in final states with a $\tau$ lepton pair. Both hadronic and leptonic decay modes are considered for the $\tau$ leptons. Scenarios involving the direct pair production of $\tau$ sleptons, or their indirect production via the decays of charginos and neutralinos, are investigated. The data correspond to an integrated luminosity of 35.9 fb$^{-1}$ collected with the CMS detector in 2016. The observed number of events is consistent with the standard model background expectation. The results are interpreted as upper limits on the cross section for $\tau$ slepton pair production in different scenarios. The strongest limits are observed in the scenario of a purely left-handed low mass $\tau$ slepton decaying to a nearly massless neutralino. Exclusion limits are also set in the context of simplified models of chargino-neutralino and chargino pair production with decays to $\tau$ leptons, and range up to 710 and 630 GeV, respectively.