Performance of the High Momentum Particle IDentification detector of ALICE during the LHC run period 2015–2016.

In the period June 2015–September 2016 the LHC has delivered pp and Pb-Pb collisions respectively at √s=13 TeV and √ s NN =5.02 TeV for a total integrated luminosity in ALICE of 14 pb −1 . The High Momentum Particle IDentification detector (HMPID) is part of the ALICE experiment. It is based on seven Ring Imaging Cherenkov (RICH) modules, 1.3×1.3 m 2 each, with a proximity focusing geometry. The Cherenkov photon detection is achieved by pad segmented photocathodes, coated with 300 nm thick Caesium Iodide layer, installed in multiwire proportional chambers. Liquid C 6 F 14 (perfluorohexane) with n=1.2989 at λ=175 nm is used as Cherenkov radiator. The HMPID identifies with three sigma separation charged π and K in the momentum range 1–3 GeV/c and protons in the range 1.5–5 GeV/c. The scatter plots of the Cherenkov angle for both pp and Pb-Pb events are presented as preliminary Particle Identification (PID) performance. After the good results shown during 2010–2013, in this paper the HMPID performance in the period 2015–2016, with emphasis on the CsI quantum efficiency stability, are presented. Finally the perspectives of the detector operation in the period HL-LHC 2019–2022, are briefly discussed. [ABSTRACT FROM AUTHOR]