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Adamczyk, L.

Publications and source records attributed to Adamczyk, L..

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DOE OSTI2013

Improved luminosity determination in pp collisions at $\sqrt {s} = 7\ \mathrm{TeV}$ using the ATLAS detector at the LHC

The luminosity calibration for the ATLAS detector at the LHC during pp collisions at √s = 7 TeV in 2010 and 2011 is presented. Evaluation of the luminosity scale is performed using several luminosity-sensitive detectors, and comparisons are made of the long-term stability and accuracy of this calibration applied to the pp collisions at √s = 7 TeV. A luminosity uncertainty of δL/L= ± 3.5 % is obtained for the 47 pb -1 of data delivered to ATLAS in 2010, and an uncertainty of δL/L= ± 1.8 % is obtained for the 5.5 fb -1 delivered in 2011.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of the inclusive jet cross-section in pp collisions at $\sqrt{s}=2.76\ \mbox{TeV}$ and comparison to the inclusive jet cross-section at $\sqrt{s} =7\ \mbox{TeV}$ using the ATLAS detector

The inclusive jet cross-section has been measured in proton–proton collisions at $\sqrt{s}=2.76\ \mbox{TeV}$ in a dataset corresponding to an integrated luminosity of 0.20 pb -1 collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-k t algorithm with two radius parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section is presented as a function of the jet transverse momentum p T and jet rapidity y, covering a range of 20 ≤ p T < 430 GeV and |y| < 4.4. The ratio of the cross-section to the inclusive jet cross-section measurement at $\sqrt{s} =7\ \mbox{TeV}$, published by the ATLAS Collaboration, is calculated as a function of both transverse momentum and the dimensionless quantity x T = 2p T / √s, in bins of jet rapidity. The systematic uncertainties on the ratios are significantly reduced due to the cancellation of correlated uncertainties in the two measurements. Results are compared to the prediction from next-to-leading order perturbative QCD calculations corrected for non-perturbative effects, and next-to-leading order Monte Carlo simulation. Furthermore, the ATLAS jet cross-section measurements at $\sqrt{s}=2.76\ \mbox{TeV}$ and $\sqrt{s} =7\ \mbox{TeV}$ are analysed within a framework of next-to-leading order perturbative QCD calculations to determine parton distribution functions of the proton, taking into account the correlations between the measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of J/ψ Azimuthal Anisotropy in Au+Au Collisions at √s NN =200 GeV

The measurement of J/ψ azimuthal anisotropy is presented as a function of transverse momentum for different centralities in Au+Au collisions at √s NN>/sub>=200 GeV. The measured J/ψ elliptic flow is consistent with zero within errors for transverse momentum between 2 and 10 GeV/c. Our measurement suggests that J/ψ particles with relatively large transverse momenta are not dominantly produced by coalescence from thermalized charm quarks, when comparing to model calculations.

Adamczyk, L.↗