Energy dependence of particle multiplicities in central Au+Au collisions.

We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at root square[s(NN)] = 200 GeV. For the 6% most central collisions, we obtain dN(ch)/d(eta)/(/eta/<1) = 650+/-35(syst). Compared to collisions at root square[s(NN)] = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

[1]  C. Henderson,et al.  Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt[s(NN)]=130 GeV. , 2001, Physical review letters.

[2]  K. J. Foley,et al.  Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV. , 2001, Physical review letters.

[3]  S. Kahana,et al.  Inclusive particle spectra at (56 and 130) A GeV , 2001 .

[4]  T. C. Sangster,et al.  Centrality dependence of charged particle multiplicity in Au-Au collisions at square root of (s)NN = 130 GeV. , 2000, Physical review letters.

[5]  M. Gyulassy,et al.  Energy and centrality dependence of rapidity densities at RHIC energies. , 2000, Physical review letters.

[6]  C. T. Zhang,et al.  Baryon rapidity loss in relativistic Au + Au collisions. , 2000, Physical review letters.

[7]  S. Jeon,et al.  Interpretation of the First Data on Central Au+Au Collisions at Square-Root of s = 56 and 130 A GeV , 2000, nucl-th/0009032.

[8]  E. al.,et al.  An excitation function of K− and K+ production in Au+Au reactions at the AGS , 2000, nucl-ex/0008010.

[9]  J. D. Deus,et al.  Particle densities in heavy ion collisions at high energy and the dual string model , 2000, hep-ph/0008086.

[10]  B. D. Bates,et al.  Charged-particle multiplicity near midrapidity in central Au+Au collisions at sqrt[SNN]=56 and 130 GeV. , 2000, Physical review letters.

[11]  Central rapidity densities of charged particles at RHIC and LHC , 2000, hep-ph/0002163.

[12]  B. Back,et al.  Excitation function of K+ and π+ production in Au + Au reactions at 2-10 AGeV , 1999 .

[13]  J. Blaizot.  Signals of the quark-gluon plasma in nucleus-nucleus collisions , 1999, hep-ph/9909434.

[14]  P. Sarin,et al.  LAYOUT AND TESTS OF SILICON PAD DETECTORS FOR THE PHOBOS EXPERIMENT AT RHIC , 1998, nucl-ex/0208006.

[15]  M. Gyulassy,et al.  HIGING: A Monte Carlo model for multiple jet production in pp, pA, and AA collisions. , 1991, Physical review. D, Particles and fields.

[16]  M. Gyulassy,et al.  Jet Quenching in Dense Matter , 1990 .

[17]  Baden,et al.  Pseudorapidity distributions of charged particles produced in p-barp interactions at sqrt s =630 and 1800 GeV. , 1989 .

[18]  James D. Bjorken,et al.  Highly Relativistic Nucleus-Nucleus Collisions: The Central Rapidity Region , 1983 .