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Obtaining the nuclear gluon distribution from heavy quark decaysto lepton pairs in pA collisions

Description: We have studied how lepton pairs from decays of heavy-flavoured mesons produced in pA collisions can be used to determine the modifications of the gluon distribution in the nucleus. Since heavyquark production is dominated by the gg channel, the ratio of correlated lepton pair cross sections from DD-bar and BB-bar decays in pA and pp collisions directly reflects the ratio R{sub g}A= f{sub g}A/f{sub g}p. We have numerically calculated the lepton pair cross sections from these decays in pp and pA collisions at SPS, RHIC and LHC energies. We find that ratio of the pA to pp cross sections agrees quite well with the input R{sub g}A. Thus, sufficiently accurate measurements could be used to determine the nuclear modification of the gluon distribution over a greater range of x and Q2 than presently available, putting strong constraints on models.
Date: May 10, 2001
Creator: Eskola, K.J.; Kolhinen, V.J. & Vogt, R.
Partner: UNT Libraries Government Documents Department

D-meson enhancement in pp collisions at the LHC due to nonlinear gluon evolution

Description: When nonlinear effects on the gluon evolution are included with constraints from HERA, the gluon distribution in the free proton is enhanced at low momentum fractions, x {approx}< 0.01, and low scales, Q{sup 2} {approx}< 10 GeV{sup 2}, relative to standard, DGLAP-evolved, gluon distributions. Consequently, such gluon distributions can enhance charm production in pp collisions at center of mass energy 14 TeV by up to a factor of five at midrapidity, y {approx} 0, and transverse momentum p{sub T} {yields} 0 in the most optimistic case. We show that most of this enhancement survives hadronization into D mesons. Assuming the same enhancement at leading and next-to-leading order, we show that the D enhancement may be measured by D{sup 0} reconstruction in the K{sup -}{pi}{sup +} decay channel with the ALICE detector.
Date: August 22, 2004
Creator: Dainese, A.; Vogt, R.; Bondila, M.; Eskola, K.J. & Kolhinen, V.J.
Partner: UNT Libraries Government Documents Department

Heavy Quarks

Description: No abstract prepared.
Date: March 27, 2006
Creator: Baines, J.; Baranov, S.P.; Behnke, O.; Bracinfk, J.; Cacciari,M.; Corradi, M. et al.
Partner: UNT Libraries Government Documents Department