Open heavy-flavour studies with the ALICE experiment at the LHC
by Dr. Elisa Meninno (University and INFN Salerno)
at SMI - Boltzmanngasse 3, 1090 Wien ( 3-2-08 - Seminarraum )
by Dr. Elisa Meninno
According to perturbative Quantum Chromo Dynamics (pQCD) calculations,strongly interacting matter at very high temperatures and/or densities exists in a particular state, called Quark-Gluon Plasma (QGP), with deconfined quarks and gluons. Such conditions of high temperatures and densities prevailed in the early universe, a few mi- croseconds after the big bang. Heavy quarks (charm and beauty) are a powerful tool to study the properties of QGP, formed in heavy-ion collisions at the LHC. Because of their large masses, heavy quarks are produced in initial hard-scattering processes, and they subsequently experience the whole system evolution, interacting with the medium constituents.
The measurement of the nuclear modification factor of open heavy-flavour hadrons can provide important information about the properties of the parton in-medium energy loss, while the measurement of the azimuthal anisotropies at low transverse momentum gives insight into the participation of the heavy quarks in the collective expansion of the system and their possible thermalisation in the medium.
The charmed baryon-to-meson ratio Λ+c -to-D0 is sensitive to hadronisation mecha- nisms. In particular, it is expected to be enhanced with respect to the proton-proton baseline if charm quarks hadronise via recombination with the surrounding light quarks in the QGP. Measurements of charm-hadron production in small systems (pp and p-Pb collisions) are a fundamental reference for measurements in Pb-Pb collisions and allow to disentangle cold nuclear matter effects from those deriving from the presence of the QGP.
The ALICE detector has excellent performance in terms of particle identification ca- pabilities and of vertexing performance and it operates at low magnetic field (B=0.5 T). All these characteristics allow one to study the heavy flavour production at very low transverse momentum, complementing results reported by other LHC experiments at higher momenta. It is therefore possible the reconstruction of charmed mesons (D0, D+, D∗+, D+s ) and baryons (Λc and Ξ0c ) and of electrons from heavy flavour hadron decays at central rapidity down to very low pT . Moreover, heavy-flavour decay muons at forward rapidity are measured via the ALICE muon spectrometer.
In this seminar, a description of several analysis strategies will be presented, together with a review of the main ALICE results on open heavy flavour.