Search in leptonic channels for heavy resonances decaying to long-lived neutral particles

TL;DR

This paper reports a search for heavy resonances decaying into long-lived neutral particles that produce distinctive lepton pairs at secondary vertices, using CMS data from 7 TeV proton-proton collisions, setting upper limits on production cross sections.

Contribution

It introduces a novel search strategy for long-lived neutral particles decaying to leptons with displaced vertices in leptonic channels at the LHC.

Findings

No significant excess above standard model expectations was observed.

Upper limits on production cross section times branching fraction were established.

The analysis constrains models predicting long-lived neutral particles.

Abstract

A search is performed for heavy resonances decaying to two long-lived massive neutral particles, each decaying to leptons. The experimental signature is a distinctive topology consisting of a pair of oppositely charged leptons originating at a separated secondary vertex. Events were collected by the CMS detector at the LHC during pp collisions at sqrt(s) = 7 TeV, and selected from data samples corresponding to 4.1 (5.1) inverse femtobarns of integrated luminosity in the electron (muon) channel. No significant excess is observed above standard model expectations, and an upper limit is set with 95% confidence level on the production cross section times the branching fraction to leptons, as a function of the long-lived massive neutral particle lifetime.