Multi-minijet Contribution to Hadronic Spectra and Correlations in Pb-Pb Collisions at 2.76 TeV and beyond

英文摘要：

In heavy-ion collisions at very high energy the density of produced jets can be so high that the possibility of hadrons produced by recombination of shower partons in overlapping minijets may become important. We study such multi-minijet contribution to the hadron spectra and to dihadron correlation in Pb-Pb collisions at 2.76 TeV at LHC. We adjust the parameter controlling the momentum degradation of semihard partons by fitting the charged-particle distribution up to $p_T\sim 16$ GeV/c. The relative magnitudes of different identified hadrons and of various partonic components are fixed by the recombination formalism. We find that the coalescence of shower patons from adjacent miniijets can be as much as from single jets for meson production, and even more so for proton, but never dominant over other components. In 3-shower-parton recombination the ratio of 2-jet to 1-jet contributions increases with collision energy; its maximum can exceed 2 at 5.5 TeV. Two-hadron correlation exhibits a broad peak on transverse rapidities, confirming that minijets play a central role at low $p_T$.