This Letter presents a search at the LHC for s-channel single top-quark production in proton-proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb-1. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of σs = 5.0 ± 4.3 pb, consistent with the Standard Model expectation.
|Titolo:||Search for s-channel single top-quark production in proton-proton collisions at √s=8 TeV with the ATLAS detector|
|Autori interni:||CONVENTI, Francesco Alessandro|
DI DONATO, CAMILLA
|Data di pubblicazione:||2015|
|Rivista:||PHYSICS LETTERS. SECTION B|
|Appare nelle tipologie:||1.1 Articolo in rivista|