Abstract

This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at sqrt(s) = 7 TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the crosssection. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt = 16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb| = 1.03+0.16−0.19 is derived assuming that the Wt production through |Vts| and |Vtd| is small.

Autore Pugliese

• Ventura Andrea , Spagnolo Stefania Antonia , Gorini Edoardo

Tutti gli autori

• G. AAD , M. BIANCO , G. CHIODINI , E. GORINI , M. PRIMAVERA , S. SPAGNOLO , A. VENTURA , ET AL.

Titolo volume/Rivista

PHYSICS LETTERS. SECTION B

Anno di pubblicazione

2012

ISSN

0370-2693

ISBN

Non Disponibile

Numero di citazioni Wos

55

Ultimo Aggiornamento Citazioni

22/04/2018

Numero di citazioni Scopus

61

Ultimo Aggiornamento Citazioni

22/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile