PACS numbers: 12.38.Mh, 25.75.-q, 13.20.Fc ELECTRONS FROM HEAVY-FLAVOUR DECAYS AT MID-RAPIDITY MEASURED IN pp COLLISIONS AT ,√s = 7 TeV AND IN Pb-Pb COLLISIONS AT s_(NN)~(1/2)= 2.76 TeV WITH ALICE AT THE LHC

摘要

We present the production cross section of electrons from heavy-flavour hadron decays measured at mid-rapidity (|η| < 0.8) with ALICE in proton-proton collisions at √s = 7 TeV. The contribution from pure beauty decays is identified using the electron displacement from the interaction vertex. The results are compared to FONLL calculations and used as pp reference for Pb-Pb collisions after scaling to the same centre-of-mass energy. In Pb-Pb collisions at √s_(NN)~(1/2) = 2.76 TeV, the inclusive electron spectrum is measured at mid-rapidity for different centrality classes and compared to a cocktail of background electrons. The corresponding nuclear modification factor of cocktail-subtracted electrons indicates heavy-flavour suppression by a factor 1.5-5 at high p_T in most central Pb-Pb collisions.