Speaker
Denise Aparecida Moreira De Godoy
(Laboratoire de Physique Subatomique et des Technologies Associe)
Description
In heavy-ion collisions at ultrarelativistic energies sufficiently high temperature and energy density can be reached to form the Quark-Gluon Plasma (QGP), a deconfined state of strongly-interacting matter. Heavy quarks, i.e. charm and beauty, are well suited to probe the interaction dynamics inside the medium, since they are mainly produced in initial hard scattering processes and experience the full evolution of the system.
The elliptic azimuthal anisotropy ($v_2$) of heavy-flavour hadrons at low transverse momentum is an observable sensitive to the collective motion of heavy quarks in the medium created in ultrarelativistic heavy-ion collisions. Moreover $v_2$ of heavy-flavour hadrons at high transverse momentum is sensitive to the path-length dependence of the energy loss of heavy quarks. Further insight into the parton energy loss within the QGP can be gained from measurements of the modification of the transverse momentum distributions of heavy flavours in heavy-ion collisions with respect to binary scaled pp collisions ($R_{\rm{AA}}$). In addiction, measurements of angular correlations between heavy-flavour hadrons and other charged hadrons in Pb-Pb collisions can give more differential access to heavy-quark energy loss and to possible modifications of the parton shower and hadronisation in the presence of the medium. Measurements of heavy-flavour correlations in pp collisions, apart from being the reference for nuclear collision systems, provide a testing ground for perturbative QCD calculations. Furthermore, heavy-flavour correlations in p-Pb collisions can be used to investigate cold nuclear matter effects and a potential existence of collective phenomena in such collisions.
The ALICE collaboration has measured the production of open heavy-flavour hadrons via their semi-electronic decays at mid-rapidity and via their semi-muonic decay channel at forward rapidity in pp collisions at $\sqrt{s}$ = 2.76 and 7 TeV, p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV, and Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. We will present the ALICE results on the elliptic azimuthal anisotropy of heavy-flavour decay leptons in Pb-Pb collisions, the nuclear modification factor of heavy-flavour decay leptons in p-Pb and Pb-Pb collisions, and the angular correlations between heavy-flavour decay electrons and charged particles in pp, p-Pb, and Pb-Pb collisions.
Author
Denise Aparecida Moreira De Godoy
(Laboratoire de Physique Subatomique et des Technologies Associe)