1020 meson production in p Pb collisions with Alice detector at the LHC

Abstract

The study of resonance production in p-Pb collisions fills the gap between pp and heavy-ion (Pb-Pb, Xe-Xe) collisions and helps us understand initial state effects due to cold nuclear matter. In this thesis, we study the and#934; (1020) mesons production using invariant mass reconstruction from their decay daughters (kaons) in p-Pb collisions. The details of ALICE detector and its subsystems are described in this thesis. We present the measurement of and#934; mesons production in p-Pb collisions at and#8730;sNN = 8.16 TeV using the ALICE detector. The nuclear modification factors (RpPb) as a function of pT for and#966; mesons at and#8730;sNN =8.16TeV are presented and compared with RpPb measurements of K*0, and#934;, and#926;, and and#937; at and#8730;sNN = 5.02 TeV. At high pT (gt 8 GeV/c), the RpPb values of all hadrons are consistent with unity within uncertainties. The RpPb of and#934; mesons at and#8730;sNN =8.16 and 5.02 TeV show no significant energy dependence. The results are compared with EPOS-LHC, DPMJET and HIJING models predictions. We also present the first measurement of multiplicity and rapidity dependence of and#934; mesons production in p-Pb collisions at and#8730;sNN = 5.02 TeV. The measured pT distributions show a dependence on both multiplicity and rapidity at low pT, whereas no significant dependence is observed at high pT. A rapidity dependence is observed in the pT-integrated yield (dN/dy), whereas the mean transverse momentum (ltpTgt) shows a flat behavior as a function of rapidity. The rapidity asymmetry (Yasym) at low pT (lt 5 GeV/c) is more significant for higher multiplicity classes. At high pT, no significant rapidity asymmetry is observed in any of the multiplicity classes. The nuclear modification factor (QCP) as a function of pT shows a Cronin-like enhancement at intermediate pT, which is more prominent at higher rapidities (Pb-going direction) and in higher multiplicity classes. At high pT (gt 5 GeV/c), the (QCP) values are greater than unity and no significant rapidity dependence is observed.The results are compared with EPOS-LHC,DPMJET,Pythia8,EPOS3and HIJING models prediction