Search for long-lived, massive particles in events with displaced vertices and missing transverse momentum in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector

TL;DR

This paper reports a search for long-lived, massive particles with displaced vertices and missing transverse momentum in 13 TeV proton-proton collisions, setting exclusion limits on gluino production up to 2.37 TeV.

Contribution

It introduces a novel search strategy targeting displaced vertices with high track multiplicity to detect long-lived particles in ATLAS data.

Findings

No significant excess over background observed.

Excludes gluino masses up to 2.37 TeV for certain lifetimes.

Provides new constraints on models of long-lived particles.

Abstract

A search for long-lived, massive particles predicted by many theories beyond the Standard Model is presented. The search targets final states with large missing transverse momentum and at least one high-mass displaced vertex with five or more tracks, and uses 32.8 fb$^{-1}$ of $\sqrt{s}$ = 13 TeV $pp$ collision data collected by the ATLAS detector at the LHC. The observed yield is consistent with the expected background. The results are used to extract 95\% CL exclusion limits on the production of long-lived gluinos with masses up to 2.37 TeV and lifetimes of $\mathcal{O}(10^{-2})$-$\mathcal{O}(10)$ ns in a simplified model inspired by Split Supersymmetry.