INVESTIGADORES
MONTICELLI Fernando Gabriel
artículos
Título:
Evidence for the associated production of a W boson and a top quark in ATLAS at √s = 7 TeV
Autor/es:
ATLAS COLLABORATION, G. AAD, F. MONTICELLI, ET AL
Revista:
PHYSICS LETTERS B
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 213 p. 1 - 23
ISSN:
0370-2693
Resumen:
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
cross-section. The result is incompatible with the background-only
hypothesis at the 3.3 sigma level, the expected sensitivity assuming the
Standard Model production rate being 3.4 sigma. The corresponding
cross-section is determined and found to be sigma_Wt = 16.8 +/- 2.9
(stat) +/- 4.9 (syst) pb, in good agreement with the Standard Model
expectation. From this result the CKM matrix element |V_{tb}| =
1.03{+0.16}{-0.19} is derived assuming that the Wt production through
|V_{ts}| and |V_{td}| is small.