Showing papers by "G. Mirabelli published in 2016"

Centrality, rapidity, and transverse momentum dependence of isolated prompt photon production in lead-lead collisions at sNN =2.76 TeV measured with the ATLAS detector

Abstract: Prompt photon production in root S-NN = 2.76-TeV Pb + Pb collisions has been measured by the ATLAS experiment at the Large Hadron Collider using data collected in 2011 with an integrated luminosity ...

Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton–lead collisions at √sNN = 5.02 TeV with the ATLAS detector

Abstract: The centrality dependence of the mean charged-particle multiplicity as a function of pseudorapidity is measured in approximately 1 mu b(-1) of proton-lead collisions at a nucleon-nucleon centre-of-mass energy of root s(NN) = 502 TeV using the ATLAS detector at the Large Hadron Collider Charged particles with absolute pseudorapidity less than 27 are reconstructed using the ATLAS pixel detector The p + Pb collision centrality is characterised by the total transverse energy measured in the Pb-going direction of the forward calorimeter The charged-particle pseudorapidity distributions are found to vary strongly with centrality, with an increasing asymmetry between the proton-going and Pb-going directions as the collisions become more central Three different estimations of the number of nucleons participating in the p + Pb collision have been carried out using the Glauber model as well as two Glauber-Gribov inspired extensions to the Glauber model Charged-particle multiplicities per participant pair are found to vary differently for these three models, highlighting the importance of including colour fluctuations in nucleon-nucleon collisions in the modelling of the initial state of p + Pb collisions

Measurement of the t (t)over-bar production cross-section using e mu events with b-tagged jets in pp collisions at root s = 7 and 8 TeV with the ATLAS detector (vol 76, pg 642, 2014)

Abstract: The ATLAS measurement of the inclusive top quark pair ( $$t\bar{t}$$ ) cross-section $$\sigma _{t\bar{t}}$$ in proton–proton collisions at $$\sqrt{s}=8$$ $$\,\mathrm{TeV}$$ has been updated using the final 2012 luminosity calibration. The updated cross-section result is: $$\begin{aligned} \sigma _{t\bar{t}}= 242.9\pm 1.7\pm 5.5\pm 5.1\pm 4.2\,\mathrm pb, \end{aligned}$$ where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity and of the LHC beam energy. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. The measurement of the ratio of $$t\bar{t}$$ cross-sections at $$\sqrt{s}=8$$ $$\,\mathrm{TeV}$$ and $$\sqrt{s}=7$$ $$\,\mathrm{TeV}$$ , and the $$\sqrt{s}=8$$ $$\,\mathrm{TeV}$$ fiducial measurement corresponding to the experimental acceptance of the leptons, have also been updated.