Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Fri, 14 Oct 2005 17:14:06 +0200 Fri, 14 Oct 2005 17:14:06 +0200 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3502 We present the first large-acceptance measurement of event-wise mean transverse momentum <pt> fluctuations for Au-Au collisions at nucleon-nucleon center-of-momentum collision energy sqrt[sNN] = 130 GeV. The observed nonstatistical <pt> 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 <pt> 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 |<1,2 pi azimuth, and 0.15 <= pt <= 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 <pt> fluctuation excess is qualitatively larger than those observed at lower energies and differs markedly from theoretical expectations. Contributions to <pt> fluctuations from semihard parton scattering in the initial state and dissipation in the bulk colored medium are discussed. J. Adams; Clemens Adler; Jens Berger; Thomas Dietel; Dominik Bernhard Flierl; Thorsten Kollegger; Jens Sören Lange; L. J. Ruan; Reinhard Stock; Christof Struck; et al.; STAR Collaboration article http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3502 Fri, 14 Oct 2005 17:14:06 +0200