Speaker
Description
The ALICE apparatus is devoted to collect pp, p-A and A-A collisions data provided by the LHC, to study the properties of strongly interacting matter under extremely high temperature and energy density conditions. In ALICE, the tracks momentum is evaluated exploiting a solenoid magnetic field of 0.5 T. Among the ALICE PID detectors, the HMPID (High Momentum Particle Identification Detector) is devoted to the identification of charged hadrons. It consists of seven identical RICH (Ring Imaging Cherenkov) counters, with liquid C$_6$F$_{14}$ as Cherenkov radiator (n $\approx$ 1.298 at $\lambda_{\rm{ph}}$ = 175 nm). Cherenkov photons and charged particles are detected by a MWPC, coupled with a pads segmented CsI coated photo-cathode. The HMPID provides 3$\sigma$ K-π and p-K separation up to $p_{\rm{T}}$ = 3 and 5 GeV/c, respectively. The detector performance depends on the experimental conditions, such as the event multiplicity and the intensity of the solenoid magnetic field. During the LHC RUN2 period (2015-2017), the HMPID collected data coming from pp, p-Pb, Pb-Pb and Xe-Xe collisions. pp data with B = 0.2 T have been also recorded. A review of the detector PID performance during LHC RUN2 period is shown. The contribution given, so far, by the HMPID to the ALICE physics measurements, performed with LHC RUN2 data, is also presented.
