Papers by Gian Paul CR Mays Chavez
Fuel and Energy Abstracts, 2011
A measurement of the cross-section for ϒ(1S) → µ + µ − production in proton-proton collisions at ... more A measurement of the cross-section for ϒ(1S) → µ + µ − production in proton-proton collisions at centre of mass energy of 7 TeV is presented. The cross-section is measured as a function of the ϒ(1S) transverse momentum in two bins of rapidity, |y ϒ(1S) | < 1.2 and 1.2 < |y ϒ(1S) | < 2.4. The measurement requires that both muons have transverse momentum p µ T > 4 GeV and pseudorapidity |η µ | < 2.5 in order to reduce theoretical uncertainties on the acceptance, which depend on the poorly known polarization. The results are based on an integrated luminosity of 1.13 pb −1 , collected with the ATLAS detector at the Large Hadron Collider. The cross-section measurement is compared to theoretical predictions: it agrees to within a factor of two with a prediction based on the NRQCD model including colour-singlet and colour-octet matrix elements as implemented in PYTHIA while it disagrees by up to a factor of ten with the next-to-leading order prediction based on the colour-singlet-model.
Fuel and Energy Abstracts, 2011
A measurement of the Z/γ⁎Z/γ⁎ transverse momentum (pTZ) distribution in proton–proton collisions ... more A measurement of the Z/γ⁎Z/γ⁎ transverse momentum (pTZ) distribution in proton–proton collisions at s=7 TeV is presented using Z/γ⁎→e+e−Z/γ⁎→e+e− and Z/γ⁎→μ+μ−Z/γ⁎→μ+μ− decays collected with the ATLAS detector in data sets with integrated luminosities of 35 pb−1 and 40 pb−1, respectively. The normalized differential cross sections are measured separately for electron and muon decay channels as well as for their combination up to pTZ of 350 GeV for invariant dilepton masses 66 GeV&lt;mℓℓ&lt;116 GeV66 GeV&lt;mℓℓ&lt;116 GeV. The measurement is compared to predictions of perturbative QCD and various event generators. The prediction of resummed QCD combined with fixed order perturbative QCD is found to be in good agreement with the data.
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Papers by Gian Paul CR Mays Chavez