Event by event < p(t) > fluctuations in Au - Au collisions at s(NN)**(1/2) = 130-GeV
Aug, 2003Citations per year
Abstract:
We present the first large-acceptance measurement of event-wise mean transverse momentum mean p_t fluctuations for Au-Au collisions at nucleon-nucleon center-of-momentum collision energy sqrt{s_{NN}} = 130 GeV. The observed non-statistical mean p_t fluctuations substantially exceed in magnitude fluctuations expected from the finite number of particles produced in a typical collision. The r.m.s. fractional width excess of the event-wise mean p_t distribution is 13.7 +/- 0.1(stat) +/- 1.3(syst)% relative to a statistical reference, for the 15% most-central collisions and for charged hadrons within pseudorapidity range |eta|<1, 2pi azimuth and 0.15 < p_t < 2 GeV/c. The width excess varies smoothly but non-monotonically with collision centrality, and does not display rapid changes with centrality which might indicate the presence of critical fluctuations. The reported mean p_t fluctuation excess is qualitatively larger than those observed at lower energies and differs markedly from theoretical expectations. Contributions to mean p_t mean fluctuations from semi-hard parton scattering in the initial state and dissipation in the bulk colored medium are discussed.Note:
- 11 pages, 2 figures, submitted to Phys. Rev. C
- 24.60.Ky
- 25.75.Gz
- nucleus nucleus: colliding beams
- scattering: heavy ion
- gold
- hadron: multiple production
- transverse momentum: moment
- transverse momentum: fluctuation
- impact parameter: dependence
- charge dependence
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