Identified Two-particle Correlations and Quantum Number Conservations in p-p and Pb-Pb Collisions at LHC Energies

Abstract: In this paper we continue the investigation of the effect of quantum number conservations of pions, kaons, and protons, with very high transverse momenta (up to 25 GeV/c), during parton fragmentation and hadronization in p-p and Pb-Pb collisions at LHC energies. The strength of the conservation effects are studied by identified two-particle correlations in Monte Carlo generated events in the mid-rapidity region ($|\eta| < 1$). The simulated p-p events were generated with PYTHIA 8, using its main default settings, at $\sqrt{s}=200$~GeV, $\sqrt{s}=2.76$~TeV, $\sqrt{s}=7$~TeV, and $\sqrt{s}=14$~TeV. In parallel to this, HIJING 1.36 was used to generate Pb-Pb events at $\sqrt{s_{\rm NN}}=2.76$~TeV with centralities $0-10\%$, $30-40\%$ and $80-90\%$. The extracted identified associated hadron spectra for charged pion, kaon, and proton show identified trigger-hadron dependent splitting between oppositely charged associated particle species in any nucleus-nucleus collisions. The Pb-Pb data exhibits a peculiar splitting pattern as a function of the transverse momentum of the associated particle $p_{T,assoc}$ both on the near and away side that is different from the patterns observed in p-p collisions. The splitting shows smooth evolution with collision energy and event multiplicity in p-p collisions while in Pb-Pb collisions different trend were observed for kaons and protons.