Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

TL;DR

This paper reports a search for long-lived heavy particles decaying into leptons or multiple charged particles in 8 TeV proton-proton collisions, setting limits on various supersymmetric models with no observed signal.

Contribution

It introduces a novel search strategy focusing on decay products of long-lived particles, applicable across multiple models, using ATLAS data at 8 TeV.

Findings

No events observed in signal regions

Limits set on supersymmetric model parameters

Search strategy applicable to various scenarios

Abstract

Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at $\sqrt{s}$ = 8 TeV corresponding to an integrated luminosity of 20.3 fb$^{-1}$ collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.