Search for Single Top tW Associated Production in the Dilepton Channel at CMS

TL;DR

This paper reports the first search for single top quark W-associated production (tW) in dileptonic channels at 7 TeV LHC data, observing an excess consistent with the Standard Model prediction.

Contribution

It introduces the first analysis of tW production in dileptonic final states at the LHC, using CMS data and novel background estimation techniques.

Findings

Observed an excess of events over background expectations.

Measured tW cross section consistent with Standard Model.

Used data-driven methods to estimate Z+jets background.

Abstract

We present a first study of the single top quark W-associated production (tW) in proton-proton collisions at the LHC at a centre-of-mass energy of 7TeV, using data collected with the CMS experiment. The search is performed in the dileptonic final states ee/e\mu/\mu\mu\ with a selection based on kinematical properties and b-tagging information. The contribution of the Z+jets processes to the background is estimated from a sideband in data. Two ttbar dominated control regions are used to constrain the normalization of top quark pair production in the signal region. An excess of events over the expected background is observed. Assigning this excess to events from tW production, the extracted tW cross section is in agreement with the Standard Model expectation.