PT Journal
AU ATLAS Collaboration (Aad, Gea
   Cabrera Urban, S
   Castillo Gimenez, V
   Costa, MJ
   Ferrer, A
   Fiorini, L
   Fuster, J
   Garcia, C
   Garcia Navarro, JE
   Gonzalez de la Hoz, S
   Hernandez Jimenez, Y
   Higon-Rodriguez, E
   Irles Quiles, A
   Kaci, M
   King, M
   Lacasta, C
   Lacuesta, VR
   Marti-Garcia, S
   Mitsou, VA
   Moles-Valls, R
   Oliver Garcia, E
   Pedraza Lopez, S
   Perez Garcia-Estañ, MT
   Romero Adam, E
   Ros, E
   Salt, J
   Sanchez Martinez, V
   Soldevila, U
   Sanchez, J
   Torro Pastor, E
   Valero, A
   Valladolid Gallego, E
   Valls Ferrer, JA
   Vos, M
TI Search for s-channel single top-quark production in proton-proton collisions at root s=8 TeV with the ATLAS detector
SO Physics Letters B
JI Phys. Lett. B
PY 2015
BP 118
EP 136
VL 740
DI 10.1016/j.physletb.2014.11.042
LA English
DE ATLAS; Top quark; Electroweak production; s-Channel
AB 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 topquark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of sigma(s) = 5.0 +/- 4.3 pb, consistent with the Standard Model expectation.
ER