Published for SISSA by Springer Received: November 11, 2012 Accepted: January 18, 2013 Published: February 14, 2013 Search in leptonic channels for heavy resonances JHEP02(2013)085 decaying to long-lived neutral particles The CMS collaboration E-mail:
[email protected] 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 sec- ondary vertex. Events were collected by the CMS detector at the LHC during pp collisions p at s = 7 TeV, and selected from data samples corresponding to 4.1 (5.1) fb−1 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. Keywords: Hadron-Hadron Scattering ArXiv ePrint: 1211.2472 Open Access, Copyright CERN, doi:10.1007/JHEP02(2013)085 for the benefit of the CMS collaboration Contents 1 Introduction1 2 The CMS detector2 3 Data and Monte Carlo simulation samples3 4 Event reconstruction and selection3 JHEP02(2013)085 4.1 Selection efficiency4 5 Background estimation and modelling5 5.1 Background normalisation5 5.2 Background shape5 6 Systematic uncertainties6 6.1 Track-finding efficiency7 6.2 Trigger efficiency measurement8 6.3 Effect of higher-order QCD corrections9 6.4 Background uncertainty9 7 Results 9 8 Summary 14 The CMS collaboration 16 1 Introduction Several models of new physics predict the existence of massive, long-lived particles which could manifest themselves through their delayed decays to leptons.