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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Measurement of the low-mass Drell-Yan differential cross section at root s=7 TeV using the ATLAS detector. J. High Energy Phys., 06(6), 112–46pp.
Abstract: The differential cross section for the process Z/gamma* -> ll (l = e, mu) as a function of dilepton invariant mass is measured in pp collisions at root s = 7 TeV at the LHC using the ATLAS detector. The measurement is performed in the e and μchannels for invariant masses between 26 GeV and 66 GeV using an integrated luminosity of 1.6 fb(-1) collected in 2011 and these measurements are combined. The analysis is extended to invariant masses as low as 12 GeV in the muon channel using 35 pb(-1) of data collected in 2010. The cross sections are determined within fiducial acceptance regions and corrections to extrapolate the measurements to the full kinematic range are provided. Next-to-next-to-leading-order QCD predictions provide a significantly better description of the results than next-to-leading-order QCD calculations, unless the latter are matched to a parton shower calculation.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Gomez-Cadenas, J. J., Izmaylov, A., Monfregola, L., et al. (2014). Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector. Phys. Rev. D, 89(9), 092003–18pp.
Abstract: The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01 +/- 0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately measured, resulting in a ratio with respect to the prediction of 0.68 +/- 0.30 and 1.10 +/- 0.14, respectively.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2014). Measurement of the inclusive nu(mu) charged current cross section on iron and hydrocarbon in the T2K on-axis neutrino beam. Phys. Rev. D, 90(5), 052010–15pp.
Abstract: We report a measurement of the nu(mu) inclusive charged current cross sections on iron and hydrocarbon in the Tokai-to-Kamioka (T2K) on-axis neutrino beam. The measured inclusive charged current cross sections on iron and hydrocarbon averaged over the T2K on-axis flux with a mean neutrino energy of 1.51 GeVare (1.444 +/- 0.002(stat)(-0.157)(+0.189)- (syst)) x 10(-38) cm(2)/ nucleon and (1.379 +/- 0.009(stat)(-0.147)(+0.178) (syst)) x 10(-38) 38 cm(2)/ nucleon, respectively, and their cross-section ratio is 1.047 +/- 0.007(stat) +/- 0.035(syst). These results agree well with the predictions of the neutrino interaction model, and thus we checked the correct treatment of the nuclear effect for iron and hydrocarbon targets in the model within the measurement precisions.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Measurement of the inclusive isolated prompt photons cross section in pp collisions at root s=7 TeV with the ATLAS detector using 4.6 fb(-1). Phys. Rev. D, 89(5), 052004–24pp.
Abstract: A measurement of the cross section for the production of isolated prompt photons in pp collisions at a center-of-mass energy root s = 7 TeV is presented. The results are based on an integrated luminosity of 4.6 fb(-1) collected with the ATLAS detector at the LHC. The cross section is measured as a function of photon pseudorapidity eta(gamma) and transverse energy E-T(gamma) in the kinematic range 100 <= E-T(gamma) < 1000 GeV and in the regions vertical bar eta(gamma)vertical bar < 1.37 and 1.52 <= vertical bar eta(gamma)vertical bar < 2.37. The results are compared to leading-order parton-shower Monte Carlo models and next-to-leading-order perturbative QCD calculations. Next-to-leading-order perturbative QCD calculations agree well with the measured cross sections as a function of E-T(gamma) and eta(gamma) .
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2014). Measurement of the Inclusive Electron Neutrino Charged Current Cross Section on Carbon with the T2K Near Detector. Phys. Rev. Lett., 113(24), 241803–7pp.
Abstract: The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies similar to 1 GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged nu(e) charged current cross section on carbon is measured to be <sigma >(phi) = 1.11 +/- 0.10(stat) +/- 0.18(syst) x 10(-38) cm(2)/nucleon. The differential and total cross- section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23 x 10(-38) cm(2)/nucleon and the GENIE prediction is 1.08 x 10(-38) cm(2)/nucleon. The total nu(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.
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