Showing papers by "Ludovico Pontecorvo published in 2010"
TL;DR: The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented in this paper, where the charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transversal momentum and charge multiplicity are measured for events with at least one charged particle in the kinematic range.
159 citations
TL;DR: A search for new heavy particles manifested as resonances in two-jet final states in 7 TeV proton-proton collisions by the LHC is presented, extending the reach of previous experiments.
Abstract: A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the LHC and correspond to an integrated luminosity of 315 nb(-1) collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% C. L. the q* mass interval 0: 30< m(q)*< 1:26 TeV, extending the reach of previous experiments.
137 citations
TL;DR: In this article, the ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons, and the drift time of the ionisation electrons is measured and used to assess the intrinsic uniformity of the CALorimeter gaps and estimate its impact on the constant term of the energy resolution.
Abstract: The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29(-0.04)(+0.05))% in the barrel and (0.54(-0.04)(+0.06))% in the endcaps. The same data are used to measure the drift velocity of ionization electrons in liquid argon, which is found to be 4.61 +/- 0.07 mm/mu s at 88.5 K and 1 kV/mm.
31 citations