Measurement of the t-channel single top-quark production cross section in pp collisions at √s=7 TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 717:4-5 (2012) 330-350
Abstract:
We report a measurement of the cross section of single top-quark production in the t-channel using 1.04 fb-1 of pp collision data at s=7 TeV recorded with the ATLAS detector at the LHC. Selected events feature one electron or muon, missing transverse momentum, and two or three jets, exactly one of them identified as originating from a b quark. The cross section is measured by fitting the distribution of a multivariate discriminant constructed with a neural network, yielding σt=83±4(stat.)-19 +20(syst.) pb, which is in good agreement with the prediction of the Standard Model. Using the ratio of the measured to the theoretically predicted cross section and assuming that the top-quark-related CKM matrix elements obey the relation |Vtb|≫|Vts|, |Vtd|, the coupling strength at the W-t-b vertex is determined to be |Vtb|=1.13-0.13 +0.14. If it is assumed that |Vtb|≤1 a lower limit of |Vtb|>0.75 is obtained at the 95% confidence level. © 2012 CERN.Measurement of the top quark pair cross section with ATLAS in pp collisions at s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 717:1-3 (2012) 89-108
Abstract:
A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb-1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction. © 2012 CERN.Production of Z0 bosons in elastic and quasi-elastic ep collisions at HERA
(2012)
ATLAS measurements of the properties of jets for boosted particle searches
Physical Review D - Particles, Fields, Gravitation and Cosmology 86:7 (2012)
Abstract:
Measurements are presented of the properties of high transverse momentum jets, produced in proton-proton collisions at a center-of-mass energy of √s=7TeV. The data correspond to an integrated luminosity of 35pb -1 and were collected with the ATLAS detector in 2010. Jet mass, width, eccentricity, planar flow and angularity are measured for jets reconstructed using the anti-kt algorithm with distance parameters R=0.6 and 1.0, with transverse momentum pT>300GeV and pseudorapidity |η|<2. The measurements are compared to the expectations of Monte Carlo generators that match leading-logarithmic parton showers to leading-order, or next-to-leading-order, matrix elements. The generators describe the general features of the jets, although discrepancies are observed in some distributions. © 2012 CERN, for the ATLAS Collaboration Published by the American Physical Society under the terms of the http://creativecommons. org/licenses/by/3.0/ Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Underlying event characteristics and their dependence on jet size of charged-particle jet events in pp collisions at √(s)=7TeV with the ATLAS detector
Physical Review D - Particles, Fields, Gravitation and Cosmology 86:7 (2012)