Measurements of the electron and muon inclusive cross-sections in proton–proton collisions at √s=7 TeV with the ATLAS detector

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Measurements of the electron and muon inclusive cross-sections in proton–proton collisions at √ s = 7 TeV with the ATLAS detector ✩ .ATLAS Collaboration a r t i c l e i n f o a b s t r a c t This Letter presents measurements of the differential cross-sections for inclusive electron and muon production in proton–proton collisions at a centre-of-mass energy of √ s = 7 TeV, using data collected by the ATLAS detector at the LHC. The muon cross-section is measured as a function of p T in the range 4 < p T < 100 GeV and within pseudorapidity |η| < 2.5. In addition the electron and muon cross-sections are measured in the range 7 < p T < 26 GeV and within |η| < 2.0, excluding 1.37 < |η| < 1.52. Integrated luminosities of 1.3 pb −1 and 1.4 pb −1 are used for the electron and muon measurements, respectively. After subtraction of the W /Z /γ * contribution, the differential cross-sections are found to be in good agreement with theoretical predictions for heavy-flavour production obtained from Fixed Order NLO calculations with NLL high-p T resummation, and to be sensitive to the effects of NLL resummation. An understanding of electron and muon production in proton– proton (pp) collisions is a prerequisite for measurements and searches including these particles in the final state. Moreover, the inclusive production of these particles can be used to constrain theoretical predictions for heavy-flavour production, for which large uncertainties exist. At low transverse momentum (p T) the inclusive electron and muon spectra are dominated by decays of charm and beauty hadrons. The contribution from W and Z /γ * production, which dominates in the higher p T region, is well understood [1] and may be subtracted in order to obtain the heavy-flavour cross-section. In measurements of b-quark production in p ¯ p collisions, an excess over the theoretical expectation was observed in earlier experiments [2–5]. This discrepancy was later resolved by improved experimental measurements [6] and the use of Next to Leading Order (NLO) with Next to Leading Log (NLL) resummation theory applied to LEP data to extract the b-quark fragmentation function [7,8]. The Tevatron data were, however, not sensitive to the p T region where the deviation between the NLO …