作者机构：
Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Bern, CH-3012 Bern, Switzerland.;Univ Birmingham, Birmingham B15 2TT, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91121 USA.
通讯机构：
[Adams, J] A;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.
摘要：
We present the centrality-dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au+Au collisions at root s(NN)=62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9 <=eta <= 3.9 and 2.3 <=eta <= 3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy-independent limiting fragmentation behavior. Photons are observed to follow a centrality-independent limiting fragmentation behavior, while for charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, and net protons in nucleus-nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons, we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy-independent behavior of limiting fragmentation, whereas the behavior of baryons is energy dependent.
作者机构：
Argonne National Laboratory, Argonne, IL 60439, United States;University of Bern, 3012 Bern, Switzerland;University of Birmingham, Birmingham, United Kingdom;Brookhaven National Laboratory, Upton, NY 11973, United States;California Institute of Technology, Pasadena, CA 91125, United States
作者：
Adams, J.*;Aggarwal, M. M.;Ahammed, Z.;Amonett, J.;Anderson, B. D.;...
期刊：
PHYSICAL REVIEW C,2006年73(6) ISSN：2469-9985
通讯作者：
Adams, J.
作者机构：
[Adams, J.] Univ Birmingham, Birmingham, W Midlands, England.;Argonne Natl Lab, Argonne, IL 60439 USA.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.;Univ Calif Berkeley, Berkeley, CA 94720 USA.
通讯机构：
[Adams, J.] U;Univ Birmingham, Birmingham, W Midlands, England.
摘要：
Measurements of two-particle correlations on angular difference variables eta(1)-eta(2) (pseudorapidity) and phi(1)-phi(2) (azimuth) are presented for all primary charged hadrons with transverse momentum 0.15 <= p(t)<= 2 GeV/c and vertical bar eta vertical bar <= 1.3 from Au-Au collisions at root s(NN)=130 GeV. Large-amplitude correlations are observed over a broad range in relative angles where distinct structures appear on the same-side and away-side (i.e., relative azimuth less than pi/2 or greater than pi/2). The principal correlation structures include that associated with elliptic flow plus a strong, same-side peak. It is hypothesized that the latter results from correlated hadrons associated with semi-hard parton scattering in the early stage of the heavy-ion collision which produces a jet-like correlation peak at small relative angles. The width of the jet-like peak on eta(1)-eta(2) increases by a factor 2.3 from peripheral to central collisions, suggesting strong coupling of semi-hard scattered partons to a longitudinally-expanding medium. The new methods of jet analysis introduced here provide access to scattered partons at low transverse momentum well below the kinematic range where perturbative quantum chromodynamics and standard fragmentation models are applicable.
作者机构：
[Abelev, B. I.] Yale Univ, New Haven, CT 06520 USA.;Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Birmingham, Birmingham, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.
通讯机构：
[Abelev, B. I.] Y;Yale Univ, New Haven, CT 06520 USA.
作者机构：
[Spinka H.M.; Krueger K.; McClain C.J.; Cadman R.V.; Underwood D.G.] Argonne National Laboratory, Argonne, IL 60439, United States;[Gaillard L.; Jones P.G.; Timmins A.R.; Burton T.P.; Barnby L.S.; Nelson J.M.] University of Birmingham, Birmingham, United Kingdom;[Ullrich T.; Love W.A.; Longacre R.S.; Didenko L.; Christie W.; Potekhin M.; Sorensen P.; Perevoztchikov V.; Ljubicic T.; Hallman T.J.; Dunlop J.C.; van Buren G.; de Phillips M.; Lebedev A.; Zhang H.; Lauret J.; Bravar A.; Ludlam T.; Laue F.; Fachini P.; Bland L.C.; Fisyak Y.; Panitkin S.Y.; LeVine M.J.; Lynn D.; Landgraf J.M.; Fine V.; Tang A.H.; Xu Z.; Ogawa A.] Brookhaven National Laboratory, Upton, NY 11973, United States;[Relyea D.; Hughes E.W.] California Institute of Technology, Pasadena, CA 91125, United States;[Crawford H.J.; Judd E.G.; Engelage J.; Perkins C.] University of California, Berkeley, CA 94720, United States
通讯机构：
[Abelev, B.I.] Y;Yale University, New Haven, CT 06520, United States
作者机构：
Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Bern, CH-3012 Bern, Switzerland.;Univ Birmingham, Birmingham B15 2TT, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.
通讯机构：
[Trainor, TA] A;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.
关键词：
Hadronization;Heavy ion collisions;Net-charge correlations;Net-charge fluctuations
摘要：
We present the first measurements of charge-dependent correlations on angular difference variables eta(1) - eta(2) (pseudorapidity) and phi(1) - phi(2) (azimuth) for primary charged hadrons with transverse momentum 0.15 <= p(t) <= 2 GeV/c and vertical bar eta vertical bar <= 1.3 from Au-Au collisions at root(s)NN = 130 GeV. We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium. (c) 2006 Elsevier B.V. All rights reserved.
作者：
Abelev, B. I.*;Aggarwal, M. M.;Ahammed, Z.;Amonett, J.;Anderson, B. D.;...
期刊：
PHYSICAL REVIEW C,2006年74(5) ISSN：2469-9985
通讯作者：
Abelev, B. I.
作者机构：
[Abelev, B. I.] Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.;Univ Birmingham, Birmingham, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.;Univ Calif Berkeley, Berkeley, CA 94720 USA.
通讯机构：
[Abelev, B. I.] A;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.
摘要：
We present the first statistically meaningful results from two-K-s(0) interferometry in heavy-ion collisions at root s(NN)=200 GeV. A model that takes the effect of the strong interaction into account has been used to fit the measured correlation function. The effects of single and coupled channels were explored. At the mean transverse mass < m(T)>=1.07 GeV, we obtain the values R=4.09 +/- 0.46(stat)+/- 0.31(sys) fm and lambda=0.92 +/- 0.23(stat)+/- 0.13(sys), where R and lambda are the invariant radius and chaoticity parameters, respectively. The results are qualitatively consistent with m(T) systematics established with pions in a scenario characterized by a strong collective flow.
作者：
Adams, J.*;Aggarwal, M. M.;Ahammed, Z.;Amonett, J.;Anderson, B. D.;...
期刊：
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS,2006年32(6):L37-L48 ISSN：0954-3899
通讯作者：
Adams, J.
作者机构：
[Adams, J.] Univ Birmingham, Birmingham, W Midlands, England.;Panjab Univ, Chandigarh 160014, India.;Ctr Variable Energy Cyclotron, Kolkata 700064, W Bengal, India.;Kent State Univ, Kent, OH 44242 USA.;Joint Inst Nucl Res Dubna, Particle Phys Lab, Dubna, Russia.
通讯机构：
[Adams, J.] U;Univ Birmingham, Birmingham, W Midlands, England.
摘要：
We present first measurements of the pseudorapidity and azimuth (eta, phi) bin-size dependence of event-wise mean transverse-momentum < pt > fluctuations for Au-Au collisions at root sNN = 200 GeV. We invert that dependence to obtain p(t) autocorrelations on differences (eta(Delta), phi(Delta)) interpreted to represent velocity/temperature distributions on (eta, phi). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary rapidly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au-Au collisions relative to peripheral or p-p collisions.
摘要：
We report on p-Lambda, p-(Lambda) over bar, (p) over bar-Lambda, and (p) over bar-(Lambda) over bar correlation functions constructed in central Au-Au collisions at root s(NN) = 200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p-Lambda and (p) over bar-(Lambda) over bar correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The p-(Lambda) over bar and (p) over bar-Lambda correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function.
作者机构：
[Abelev, B. I.] Yale Univ, New Haven, CT 06520 USA.;Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Birmingham, Birmingham, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.
通讯机构：
[Abelev, B. I.] Y;Yale Univ, New Haven, CT 06520 USA.
作者机构：
Argonne National Laboratory, Argonne, Illinois 60439;[Adams, J.; Barnby, L.S.] University of Birmingham, Birmingham, United Kingdom;Brookhaven National Laboratory, Upton, New York 11973;California Institute of Technology, Pasadena, California 91125;University of California, Berkeley, California 94720
期刊：
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS,2006年32(8):1121-1129 ISSN：0954-3899
通讯作者：
Lu, Y.
作者机构：
[Lu, Y.] Huazhong Normal Univ, Cent China Normal Univ, Inst Particle Phys, IOPP, Wuhan 430079, Peoples R China.;Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA.;Goethe Univ Frankfurt, Inst Theoret Phys, D-60438 Frankfurt, Germany.;Brookhaven Natl Lab, Upton, NY 11973 USA.;FIAS, D-60438 Frankfurt, Germany.
通讯机构：
[Lu, Y.] H;Huazhong Normal Univ, Cent China Normal Univ, Inst Particle Phys, IOPP, Wuhan 430079, Peoples R China.
摘要：
The transverse momentum dependence of the anisotropic flow $v_2$ for $\pi$, $K$, nucleon, $\Lambda$, $\Xi$ and $\Omega$ is studied for Au+Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV within two independent string-hadron transport approaches (RQMD and UrQMD). Although both models reach only 60% of the absolute magnitude of the measured $v_2$, they both predict the particle type dependence of $v_2$, as observed by the RHIC experiments: $v_2$ exhibits a hadron-mass hierarchy (HMH) in the low $p_T$ region and a number-of-constituent-quark (NCQ) dependence in the intermediate $p_T$ region. The failure of the hadronic models to reproduce the absolute magnitude of the observed $v_2$ indicates that transport calculations of heavy ion collisions at RHIC must incorporate interactions among quarks and gluons in the early, hot and dense phase. The presence of an NCQ scaling in the string-hadron model results suggests that the particle-type dependencies observed in heavy-ion collisions at intermediate $p_T$ might be related to the hadronic cross sections in vacuum rather than to the hadronization process itself. Comment: 10 pages, 5 figures; A new author (H. Petersen) is added; A new figure (fig.1) on time evolution of elliptic flow and number of collisions is added; Version accepted for publication in J. Phys. G
作者机构：
[Ablikim, M.] Inst High Energy Phys, Beijing 100039, Peoples R China.;CCAST, Beijing 100080, Peoples R China.;Guangxi Normal Univ, Guilin 541004, Peoples R China.;Henan Normal Univ, Xinxiang 453002, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430070, Peoples R China.
通讯机构：
[Ablikim, M.] I;Inst High Energy Phys, Beijing 100039, Peoples R China.
作者机构：
Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Bern, CH-3012 Bern, Switzerland.;Univ Birmingham, Birmingham B15 2TT, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.
通讯机构：
[Adams, J] A;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.
摘要：
We present the directed flow (v(1)) measured in Au+Au collisions at root s(NN)=62.4 GeV in the midpseudorapidity region parallel to eta parallel to < 1.3 and in the forward pseudorapidity region 2.5 <parallel to eta parallel to < 4.0. The results are obtained using the three-particle cumulant method, the event plane method with mixed harmonics, and for the first time at the Relativistic Heavy Ion Collider, the standard method with the event plane reconstructed from spectator neutrons. Results from all three methods are in good agreement. Over the pseudorapidity range studied, charged particle directed flow is in the direction opposite to that of fragmentation neutrons.
摘要：
We present the first measurement of pseudorapidity distribution of photons in the region 2.3 < or = eta < or = 3.7 for different centralities in Au+Au collisions at square root of (S(NN)) = 62.4 GeV. We find that the photon yield scales with the number of participating nucleons at all collision centralities studied. The pseudorapidity distribution of photons, dominated by pi0 decays, has been compared to those of charged pions, photons, and inclusive charged particles from heavy-ion and nucleon-nucleon collisions at various energies. The photon production has been shown to be consistent with the energy and centrality independent limiting fragmentation scenario.
