Physical Review C 71,6 (2005) 064906;
We present the first large-acceptance measurement of event-wise mean transverse momentum < p(t)> fluctuations for Au-Au collisions at nucleon-nucleon center-of-momentum collision energy root s(NN) = 130 GeV. The observed nonstatistical < 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 < 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 vertical bar eta vertical bar < 1,2 pi azimuth, and 0.15 <= p(t) <= 2 GeV/c. The width excess varies smoothly but nonmonotonically with collision centrality and does not display rapid changes with centrality which might indicate the presence of critical fluctuations. The reported < p(t)> fluctuation excess is qualitatively larger than those observed at lower energies and differs markedly from theoretical expectations. Contributions to < p(t)> fluctuations from semihard parton scattering in the initial state and dissipation in the bulk colored medium are discussed.
heavy-ion collisions;; transverse-momentum;; nuclear collisions;; dynamics;; physics;; model
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