Search for Z' resonances decaying to ttbar in dilepton+jets final states in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper searches for Z' resonances decaying to top quark pairs in proton-proton collisions at 7 TeV, setting upper limits on production cross sections and excluding certain Z' mass ranges at 95% confidence level.

Contribution

It provides the first limits on Z' resonances decaying to top quark pairs in dilepton+jets final states at 7 TeV, excluding specific mass ranges for leptophobic topcolor Z' particles.

Findings

No significant excess over standard model background.

Excluded Z' masses below 1.3 TeV and 1.9 TeV for different widths.

Set upper limits on production cross sections for Z' resonances.

Abstract

A search for resonances decaying to top quark-antiquark pairs is performed using a dilepton+jets data sample recorded by the CMS experiment at the LHC in pp collisions at sqrt(s) = 7 TeV corresponding to an integrated luminosity of 5.0 inverse femtobarns. No significant deviations from the standard model background are observed. Upper limits are presented for the production cross section times branching fraction of top quark-antiquark resonances for masses from 750 to 3000 GeV. In particular, the existence of a leptophobic topcolor particle Z' is excluded at the 95% confidence level for resonance masses M[Z'] < 1.3 TeV for Gamma[Z'] = 0.012 M[Z'], and M[Z'] < 1.9 TeV for Gamma[Z'] = 0.10 M[Z'].