Electrons from decays of open charm and beauty hadrons in p-Pb collisions at √(s_NN)=5.02 TeV

Charm and beauty quarks serve as a probe to study the deconfined medium of a quark-gluon plasma observed in A-A collisions. Due to their large mass they are produced in the first moments of the collision and interact with the expanding medium. Cold nuclear matter effects such as the modification of the nuclear Parton Distribution Functions in the Pb nuclei, parton momentum (k_T) broadening from soft scattering processes and initial- and final-state parton energy loss play a role in nuclear collisions. These effects can be studied by a reference measurement in p-A collisions, where an extended medium is not believed to be formed. In this work the measurement of the production of electrons from semi-leptonic decays of heavy-flavor hadrons as function of the transverse momentum in p-Pb collisions at √(s_NN)=5.02 TeV with ALICE at the LHC is presented. The measurement of electrons from heavy-flavor hadron decays requires a precise determination of the electron background. For the first time in this kind of measurement with ALICE the main contribution to the electron background is estimated by tagging electrons from e⁺e^-γ Dalitz decays and γ-conversions, leading to a substantial reduction of the relative systematic uncertainties compared to previous measurements in pp collisions. A reference measurement for pp collisions at √(s)=5.02 TeV was interpolated from measurements in pp collisions at √(s)=2.76 TeV and √(s)=7 TeV. The determined nuclear modification factor of electrons measured in the p_T-range 0.5T<8 GeV/c and rapidity range -1.065cms<0.135 suggests binary-scaling of the production cross-section measured in p-Pb collisions. The result for the R_pPb suggests small cold nuclear matter effects for electrons from heavy-flavor hadron decays in agreement with predictions from different model calculations. An investigation of the multiplicity dependence of heavy-flavor production leads to linear increase of the self-normalized yields of electrons from heavy-flavor hadron decays as function of the charged-particle multiplicity estimated at mid-rapidity and backward rapidity in p-Pb collisions at √(s_NN)=5.02 TeV. The self-normalized yields show no p_T-dependence as function of the multiplicity, which indicates small or no differences between the charm and beauty production as function of multiplicity.