Separation of electrons from charm- and beauty hadron decays in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with ALICE

20 May 2014, 16:30
spectrum (darmstadtium)



Board: F-59
Poster Open Heavy Flavour and Quarkonia Poster session


Martin Völkl


The ALICE Collaboration at the LHC studies nucleus-nucleus collisions with the aim of investigating the properties of the high energy density state of strongly-interacting matter produced in heavy-ion collisions, the Quark-Gluon Plasma (QGP). Heavy quarks (charm and beauty) are an effective probe to investigate the properties of the QGP. They are produced almost exclusively in the initial partonic scattering processes and they interact strongly with the surrounding matter throughout its evolution. Moreoever, the in-medium parton energy loss is expected to depend both on the parton mass and its colour charge making flavour-separated measurements of charm and beauty useful to test models of in-medium energy loss. Experimentally one way to measure heavy quarks is via electrons from semileptonic decays of heavy-flavour hadrons. The comparison of the $p_{\rm T}$ spectra of heavy-flavour decay electrons in pp and Pb-Pb collisions gives insight into the energy loss of heavy quarks in the QGP. To achieve a flavour-separated measurement of heavy-flavour decay electrons, first the electrons have to be identified. This is done using the excellent particle identification capabilities of ALICE. In addition the electrons have to be separated according to their source (e.g. charm and beauty hadron decays, $\pi^{0}$ Dalitz decays, photon conversion etc.). This separation is done statistically using the impact parameter of the electrons. The latter is typically larger for electrons from hadrons containing a beauty quark due to the larger mean proper decay length ($c\tau\approx500 \mu \mathrm{m}$) of these hadrons compared to other hadrons decaying into electrons. In this poster the current status of the analysis is presented for pp collisions at $\sqrt{s}$ = 7 TeV and for Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV.
On behalf of collaboration: ALICE

Primary author

Martin Völkl

Presentation Materials