Erratum to: Measurement of D*(+/-) meson production and determination of F-2(c(c)over-bar) at low Q(2) in deep-inelastic scattering at HERA

Inclusive production of D* mesons in deep-inelastic ep scattering at HERA is studied in the range 5 LT Q(2) LT 100 GeV2 of the photon virtuality and 0.02 LT y LT 0.7 of the inelasticity of the scattering process. The observed phase space for the D* meson is (pT) (D*) GT 1.25 GeV and |eta( D*)| LT 1.8. The data sample corresponds to an integrated luminosity of 348 pb(-1) collected with the H1 detector. Single and double differential cross sections are measured and the charm contribution F-2(c (c) over bar) to the proton structure function F-2 is determined. The results are compared to perturbative QCD predictions at next-to-leading order implementing different schemes for the charm mass treatment and with Monte Carlo models based on leading order matrix elements with parton showers

Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA

A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) GT 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb

Jet production in ep collisions at low Q(2) and determination of alpha(s)

The production of jets is studied in deep-inelastic e(+) p scattering at low negative four momentum transfer squared 5 LT Q(2) LT 100 GeV2 and at inelasticity 0.2 LT y LT 0.7 using data recorded by the H1 detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb(-1). Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of Q(2) and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction xi. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling as

Measurement of the production cross section for W-bosons in association with jets in pp collisions at root s=7 TeV with the ATLAS detector

This Letter reports on a first measurement of the inclusive W + jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W-boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections sigma (W + GT = n)/sigma(W + GT = n - 1) for inclusive jet multiplicities n = 1-4. The results, based on an integrated luminosity of 1.3 pb(-1), have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-to-leading order calculations, studied here for n LT = 2, are found in good agreement with the data. Leading-order multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved

Measurement of the inclusive isolated prompt photon cross section in pp collisions at root s=7 TeV with the ATLAS detector

A measurement of the cross section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy root s = 7 TeV is presented. The measurement covers the pseudorapidity ranges vertical bar eta(gamma)vertical bar LT 1: 37 and 1: 52 LT = vertical bar eta(gamma)vertical bar LT 1: 81 in the transverse energy range 15 LT = E-T(gamma) LT 100 GeV. The results are based on an integrated luminosity of 880 nb(-1), collected with the ATLAS detector at the Large Hadron Collider. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed distribution of the transverse isolation energy in a narrow cone around the photon candidate. The results are compared to predictions from next-to-leading-order perturbative QCD calculations

Search for tb Resonances in Proton-Proton Collisions at root s=7 TeV with the ATLAS Detector

This Letter presents a search for tb resonances in 1.04 fb(-1) of LHC proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 7 TeV. Events with a lepton, missing transverse momentum, and two jets are selected and the invariant mass of the corresponding final state is reconstructed. The search exploits the shape of the tb invariant mass distribution compared to the expected standard model backgrounds. The model of a right-handed W(R) with standard model-like couplings is chosen as the benchmark model for this search. No statistically significant excess of events is observed in the data, and upper limits on the cross section times the branching ratio of W(R) resonances at 95% C.L. lie in the range of 6.1-1.0 pb for W(R) masses ranging from 0.5 to 2.0 TeV. These limits are translated into a lower bound on the allowed right-handed W(R) mass, giving mW(R) GT 1.13 TeV at 95% C.L

Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in root s=7 TeV proton-proton collisions

Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or mu. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1 fb(-1) of root s = 7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite-sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective production cross sections in excess of 9.9 fb for opposite-sign events containing supersymmetric particles with missing transverse momentum greater than 250 GeV are excluded at 95% CL For same-sign events containing supersymmetric particles with missing transverse momentum greater than 100 GeV, effective production cross sections in excess of 14.8 fb are excluded at 95% CL The latter limit is interpreted in a simplified electroweak gaugino production model excluding chargino masses up to 200 GeV, under the assumption that slepton decay is dominant. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved

Search for the Standard Model Higgs Boson in the Diphoton Decay Channel with 4.9 fb(-1) of pp Collision Data at root s=7 TeV with ATLAS

A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of 4.9 fb(-1) collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of root s = 7 TeV. In the diphoton mass range 110-150 GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5 GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110-150 GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113-115 GeV and 134.5-136 GeV

Measurement of tau polarization in W - GT tau nu decays with the ATLAS detector in pp collisions at root s=7 TeV

In this paper, a measurement of tau polarization in W - GT tau nu decays is presented. It is measured from the energies of the decay products in hadronic tau decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb(-1), were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the tau polarization is P-tau = -1.06 +/- 0.04 (stat)(-0.07)(+0.05) (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95 % CL interval [-1,-0.91]. Measurements of tau polarization have not previously been made at hadron colliders