Heavy lepton pair production in nucleus-nucleus collisions at LHC energy - a case study

We present a study of tau(+)tau(-) lepton pair production in Pb + Pb collisions at root s(NN) = 5.5 TeV. The larger tau(+/-) mass (similar to 1.77 GeV) compared to e(+/-) and mu(+/-) leads to considerably small hadronic contribution to the tau(+)tau(-) pair invariant mass (M) distribution relative to the production from thermal partonic sources. The quark anti-quark annihilation processes via intermediary virtual photon. Z and Higgs bosons have been considered for the production of tau(+)tau(-). We observe that the contribution from Drell-Yan process dominates over thermal yield for tau(+)tau(-) pair mass from 4 to 20 GeV at the LHC energy. We also present the ratio of tau lepton pair yields for nucleus-nucleus collisions relative to yields from p + p collisions scaled by number of binary collisions at LHC energies as a function tau pair mass. The ratio is found to be significantly above unity for the mass range 4 to 6 GeV. This indicates the possibility of detecting tau(+)tau(-) pair from quark-gluon plasma (QGP) in the mass window 4 <= M(GeV) <= 6. (C) 2012 Elsevier B.V. All rights reserved.