Skip to main content
eScholarship
Open Access Publications from the University of California

UC Santa Cruz

UC Santa Cruz Previously Published Works bannerUC Santa Cruz

Measurement of the production cross-section of a single top quark in association with a W boson at 8 TeV with the ATLAS experiment

  • Author(s): The ATLAS collaboration;
  • Aad, G;
  • Abbott, B;
  • Abdallah, J;
  • Abdinov, O;
  • Aben, R;
  • Abolins, M;
  • AbouZeid, OS;
  • Abramowicz, H;
  • Abreu, H;
  • Abreu, R;
  • Abulaiti, Y;
  • Acharya, BS;
  • Adamczyk, L;
  • Adams, DL;
  • Adelman, J;
  • Adomeit, S;
  • Adye, T;
  • Affolder, AA;
  • Agatonovic-Jovin, T;
  • Agricola, J;
  • Aguilar-Saavedra, JA;
  • Ahlen, SP;
  • Ahmadov, F;
  • Aielli, G;
  • Akerstedt, H;
  • Åkesson, TPA;
  • Akimov, AV;
  • Alberghi, GL;
  • Albert, J;
  • Albrand, S;
  • Alconada Verzini, MJ;
  • Aleksa, M;
  • Aleksandrov, IN;
  • Alexa, C;
  • Alexander, G;
  • Alexopoulos, T;
  • Alhroob, M;
  • Alimonti, G;
  • Alio, L;
  • Alison, J;
  • Alkire, SP;
  • Allbrooke, BMM;
  • Allport, PP;
  • Aloisio, A;
  • Alonso, A;
  • Alonso, F;
  • Alpigiani, C;
  • Altheimer, A;
  • Alvarez Gonzalez, B;
  • Álvarez Piqueras, D;
  • Alviggi, MG;
  • Amadio, BT;
  • Amako, K;
  • Amaral Coutinho, Y;
  • Amelung, C;
  • Amidei, D;
  • Amor Dos Santos, SP;
  • Amorim, A;
  • Amoroso, S;
  • Amram, N;
  • Amundsen, G;
  • Anastopoulos, C;
  • Ancu, LS;
  • Andari, N;
  • Andeen, T;
  • Anders, CF;
  • Anders, G;
  • Anders, JK;
  • Anderson, KJ;
  • Andreazza, A;
  • Andrei, V;
  • Angelidakis, S;
  • Angelozzi, I;
  • Anger, P;
  • Angerami, A;
  • Anghinolfi, F;
  • Anisenkov, AV;
  • Anjos, N;
  • Annovi, A;
  • Antonelli, M;
  • Antonov, A;
  • Antos, J;
  • Anulli, F;
  • Aoki, M;
  • Aperio Bella, L;
  • Arabidze, G;
  • Arai, Y;
  • Araque, JP;
  • Arce, ATH;
  • Arduh, FA;
  • Arguin, JF;
  • Argyropoulos, S;
  • Arik, M;
  • Armbruster, AJ;
  • Arnaez, O;
  • Arnold, H;
  • Arratia, M;
  • Arslan, O;
  • Artamonov, A
  • et al.
Abstract

The cross-section for the production of a single top quark in association with a W boson in proton-proton collisions at √s = 8TeV is measured. The dataset corresponds to an integrated luminosity of 20.3 fb−1, collected by the ATLAS detector in 2012 at the Large Hadron Collider at CERN. Events containing two leptons and one central b-jet are selected. The W t signal is separated from the backgrounds using boosted decision trees, each of which combines a number of discriminating variables into one classifier. Production of W t events is observed with a significance of 7.7σ. The cross-section is extracted in a profile likelihood fit to the classifier output distributions. The W t cross-section, inclusive of decay modes, is measured to be 23.0 ± 1.3(stat.)− 3.5+ 3.2(syst.)±1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |Vtb| of 1.01 ± 0.10 and a lower limit of 0.80 at the 95% confidence level. The cross-section for the production of a top quark and a W boson is also measured in a fiducial acceptance requiring two leptons with pT> 25 GeV and |η| < 2.5, one jet with pT> 20 GeV and |η| < 2.5, and ETmiss > 20 GeV, including both W t and top-quark pair events as signal. The measured value of the fiducial cross-section is 0.85 ± 0.01(stat.)− 0.07+ 0.07(syst.)±0.03(lumi.) pb.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View