Evidence for the associated production of a W boson and a top quark in ATLAS at
详细信息 查看全文
- 作者：ATLAS Collaboration ; G. Aad ; B. Abbott ; J. Abdallah ; S. Abdel Khalek ; A.A. Abdelalim ; O. Abdinov ; B. Abi ; M. Abolins ; O.S. AbouZeid ; H. Abramowicz ; H. Abreu ; E. Acerbi ; B.S. Acharya ; L. Adamczyk ; D.L. Adams ; T.N. Addy ; J. Adelman ; S. Adomeit ; P. Adragna ; et al.
- 关键词：ATLAS ; Top quark ; W+t ; Single top-quark
- 刊名：Physics Letters B
- 出版年：2012
- 出版时间：17 September, 2012
- 年：2012
- 卷：716
- 期：1
- 页码：142-159
- 全文大小：1080 K
文摘
This Letter presents evidence for the associated production of a W boson and a top quark using of pp collision data at 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 cross-section. The result is incompatible with the background-only hypothesis at the 3.3¦Ò level, the expected sensitivity assuming the Standard Model production rate being 3.4¦Ò. The corresponding cross-section is determined and found to be , in good agreement with the Standard Model expectation. From this result the CKM matrix element is derived assuming that the Wt production through and is small.