作者:
Adams, J.*;Aggarwal, M. M.;Ahammed, Z.;Amonett, J.;Anderson, B. D.;...
期刊:
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS,2007年34(5):799-816 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.;Bhabha Atom Res Ctr, Ctr Variable Energy Cyclotron, Kolkata 700064, W Bengal, India.;Kent State Univ, Kent, OH 44242 USA.;Univ Calif Davis, Davis, CA 95616 USA.
通讯机构:
[Adams, J.] U;Univ Birmingham, Birmingham, W Midlands, England.
摘要:
Measurements of two-particle correlations on transverse momentum p(t) for Au-Au collisions at root s(NN) = 130 GeV are presented. Significant large-momentum-scale correlations are observed for charged primary hadrons with 0.15 <= p(t) <= 2 GeV/c and pseudorapidity vertical bar eta vertical bar <= 1.3. Such correlations were not observed in a similar study at lower energy and are not predicted by theoretical collision models. Their direct relation to mean-p(t) fluctuations measured in the same angular acceptance is demonstrated. Positive correlations are observed for pairs of particles which have large p(t) values while negative correlations occur for pairs in which one particle has large p(t) and the other has much lower p(t). The correlation amplitudes per final state particle increase with collision centrality. The observed correlations are consistent with a scenario in which the transverse momentum of hadrons associated with initial-stage semi-hard parton scattering is dissipated by the medium to lower p(t).
作者:
Xiao, Z. G.*;Dong, X.;Liu, F.;Luo, X. F.;Wu, K. J.;...
期刊:
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS,2007年34(8):S915-S919 ISSN:0954-3899
通讯作者:
Xiao, Z. G.
作者机构:
[Xiao, Z. G.] Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China.;Univ Sci & Technol China, Hefei 230026, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA.
通讯机构:
[Xiao, Z. G.] C;Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China.
会议名称:
19th International Conference on Ultra-Relativistic Necleus-Nucleus Collisions
会议时间:
NOV 14-20, 2006
会议地点:
Shanghai, PEOPLES R CHINA
会议主办单位:
Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China.^Univ Sci & Technol China, Hefei 230026, Peoples R China.^Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.^Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA.
作者机构:
[Zhang Zong-Ye] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;CCAST, World Lab, Beijing 100080, Peoples R China.
通讯机构:
[Zhang Zong-Ye] C;Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.
摘要:
We report the statistical properties of three bus-transport networks (BTN) in three different cities of China. These networks are composed of a set of bus lines and stations serviced by these. Network properties, including the degree distribution, clustering and average path length are studied in different definitions of network topology. We explore scaling laws and correlations that may govern intrinsic features of such networks. Besides, we create a weighted network representation for BTN with lines mapped to nodes and number of common stations to weights between lines. In such a representation, the distributions of degree, strength and weight are investigated. A linear behavior between strength and degree s(k)∼k is also observed.
作者机构:
[Abelev, B. I.] Univ Illinois, Urbana, IL 61801 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.] U;Univ Illinois, Urbana, IL 61801 USA.
摘要:
Structural properties of the ship-transport network of China (STNC) are studied in the light of recent investigations of complex networks. STNC is composed of a set of routes and ports located along the sea or river. Network properties including the degree distribution, degree correlations, clustering, shortest path length, centrality, and betweenness are studied in different definitions of network topology. It is found that geographical constraint plays an important role in the network topology of STNC. We also study the traffic flow of STNC based on the weighted network representation, and demonstrate the weight distribution can be described by power-law or exponential function depending on the assumed definition of network topology. Other features related to STNC are also investigated.
作者机构:
[Wu Ke-Jun; Liu Feng; Wu, KJ] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构:
[Wu Ke-Jun] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
mean field;deformation;transverse flow;shadowing
摘要:
The ART(a Relativistic Transport) Model is applied for studying the UU collisions at a beam kinetic energy about 0.52GeV/nucleon. We discuss the time evolution and the centrality dependence for sideward flow of nucleons and pions at two extreme orientation UU collisions. It is found that the collective (side) flow is developed in the high density region and has a saturation in the expansion phase, so it is a sensitive probe for the reaction dynamics in the high density region. A distinct transition from pion flow to antiflow, which is relative to nucleons flow, occurs at the impact parameters of about 8fm and 2fm in tip-tip and body-body UU collisions, respectively. The pion flow is a result of the competition between the collective flow of baryon resonances and the shadowing of spectators through rescatterings and reabsorptions.
作者:
Abelev, B. I.*;Aggarwal, M. M.;Ahammed, Z.;Anderson, B. D.;Arkhipkin, D.;...
期刊:
PHYSICAL REVIEW C,2007年75(5) ISSN:2469-9985
通讯作者:
Abelev, B. I.
作者机构:
[Abelev, B. I.] Yale Univ, New Haven, CT 06520 USA.;Carnegie Mellon Univ, Pittsburgh, PA 15213 USA.;Univ Illinois, Chicago, IL USA.;Creighton Univ, Omaha, NE 68178 USA.;Acad Sci Czech Republ, Inst Nucl Phys, CZ-25068 Rez, Czech Republic.
通讯机构:
[Abelev, B. I.] Y;Yale Univ, New Haven, CT 06520 USA.
摘要:
We present STAR measurements of the azimuthal anisotropy parameter v(2) for pions, kaons, protons, Lambda,(Lambda) over bar,Xi+ (Xi) over bar, and Omega+ (Omega) over bar, along with v(4) for pions, kaons, protons, and Lambda+(Lambda) over bar at midrapidity for Au+Au collisions at root s(NN)=62.4 and 200 GeV. The v(2)(p(T)) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v(2) values at 62.4, 130, and 200 GeV are as little as 10-15% larger than those in Pb+Pb collisions at root s(NN)=17.3 GeV. At intermediate transverse momentum (p(T) from 1.5-5 GeV/c), the 62.4 GeV v(2)(p(T)) and v(4)(p(T)) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon v(2) is larger than antibaryon v(2) at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances v(2) or that antibaryon and baryon annihilation is larger in the in-plane direction.
作者机构:
[Xu Xin-Ping; Xu, XP; Liu Feng] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构:
[Xu Xin-Ping] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
random graphs;configuration model;correlations
摘要:
Recently, random graphs in which vertices are characterized by hidden variables controlling the establishment of edges between pairs of vertices have attracted much attention. This paper presents a specific realization of a class of random network models in which the connection probability between two vertices (i,j) is a specific function of degrees ki and kj. In the framework of the configuration model of random graphs, we find the analytical expressions for the degree correlation and clustering as a function of the variance of the desired degree distribution. The obtained expressions are checked by means of numerical simulations. Possible applications of our model are discussed.
作者机构:
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.;Univ Calif Berkeley, Berkeley, CA 94720 USA.
通讯机构:
[Mohanty, B.] A;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.
摘要:
We study the energy dependense of the transverse momentum (PT) spectra for charged pions, protons and anti-protons for An + An collisions at root(NN)-N-s = 62.4 and 200 GeV. Data are presented at mid-rapidity (broken vertical bar y broken vertical bar < 0.5) for 0.2 < PT < 12 GeV/c. In the intermediate PT region (2 < PT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher PT (PT > 7 GeV/c) the modification is similar for both energies. The p/pi(+) and (p) over bar/pi(-) ratios for central collisions at root(NN)-N-s = 62.4 GeV peak at PT similar or equal to 2 GeV/c. In the PT range where recombination is expected to dominate, the p/pi(+) ratios at 62.4 GeV are larger than at 200 GeV, while the (p) over bar/pi(-) ratios are smaller. For PT > 2 GeV/c, the (p) over bar/pi(-) ratios at the two beam energies are independent of P-T and centrality indicating that the dependence of the (p) over bar/pi(-) ratio on P-T does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence. (C) 2007 Elsevier B.V. All rights reserved.
作者:
Abelev, B. I.*;Adams, J.;Aggarwal, M. M.;Ahammed, Z.;Amonett, J.;...
期刊:
PHYSICAL REVIEW C,2007年75(6) ISSN:2469-9985
通讯作者:
Abelev, B. I.
作者机构:
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.;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 strange particle spectra and yields measured at midrapidity in root s = 200 GeV proton-proton (p + p) collisions at the BNL Relativistic Heavy Ion Collider (RHIC). We find that the previously observed universal transverse mass (m(T) = root PT2 + m(2)) scaling of hadron production in p + p collisions seems to break down at higher m(T) and that there is a difference in the shape of the m(T) spectrum between baryons and mesons. We observe midrapidity antibaryon to baryon ratios near unity for Lambda and Xi baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum < p(T)> on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared with previous measurements made at the CERN Super Proton Synchrotron and Intersecting Storage Rings and in Fermilab experiments and with leading-order and next-to-leading-order string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from p + p collisions at RHIC energies have large contributions from gluon jets rather than from quark jets.
作者:
Abelev, B. I.*;Aggarwal, M. M.;Ahammed, Z.;Anderson, B. D.;Arkhipkin, D.;...
期刊:
PHYSICAL REVIEW C,2007年76(2) ISSN:2469-9985
通讯作者:
Abelev, B. I.
作者机构:
[Abelev, B. I.] Univ Illinois, Chicago, IL 60607 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.] U;Univ Illinois, Chicago, IL 60607 USA.
摘要:
The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Lambda and (Lambda) over bar hyperon global polarization measurements in Au+Au collisions at root s(NN)=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of Lambda and (Lambda) over bar hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P-Lambda,P-(Lambda) over bar|<= 0.02, is compared with the theoretical values discussed recently in the literature.
作者:
Abelev, B. I.*;Aggarwal, M. M.;Ahammed, Z.;Anderson, B. D.;Arkhipkin, D.;...
期刊:
PHYSICAL REVIEW C,2007年76(1) ISSN:2469-9985
通讯作者:
Abelev, B. I.
作者机构:
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.;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 have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at root s(NN)=200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order >= 0.1 ns, in contrast to limits over ten times longer in BNL Alternating Gradient Synchrotron (AGS) studies and longer still at the CERN Super Proton Synchrotron (SPS). Upper limits of a few 10(-6) to 10(-7) per central Au+Au collision are set for strangelets with mass greater than or similar to 30 GeV/c(2).
作者机构:
[Abelev, B. I.] Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA.;Univ Birmingham, Birmingham B15 2TT, 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.
作者机构:
[Xu, Xinping] HuaZhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.;Giamgxi Normal Univ, Coll Phys & Elect Engn, Guilin 541004, Peoples R China.
通讯机构:
[Xu, Xinping] H;HuaZhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
game theory;complex networks;topology;social sciences
摘要:
Tournaments of the game of Go can be represented as a directed network in which the vertices are players and a directed link is pointing from the winner to the loser for each game. In this article, we present some interesting results for the network of Asian Go players, which is composed of 756 Go players and 9473 tournaments. It is found that the topological structure of this network displays the small-world property and a significant rich-club phenomenon where high-degree nodes are tightly interconnected. In addition, we consider the weighted version of the network, and find the weights obey power-law distributions, while the strengths follow stretched exponential distributions. The time evolution of the network structure is studied and the corresponding results discussed. The analysis of this work provides a deeper understanding for the competition network structure of Asian Go players.
作者:
Wang, W. L.*;Huang, F.;Zhang, Z. Y.;Yu, Y. W.(俞云伟);Liu, F.
期刊:
EUROPEAN PHYSICAL JOURNAL A,2007年32(3):293-297 ISSN:1434-6001
通讯作者:
Wang, W. L.
作者机构:
[Wang, W. L.] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.;CCAST, World Lab, Beijing 100080, Peoples R China.;Inst High Energy Phys, Beijing 100039, Peoples R China.
通讯机构:
[Wang, W. L.] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.
作者机构:
[Cadman, R. V.; Krueger, K.; McClain, C. J.; Spinka, H. M.; Underwood, D. G.] Argonne Natl Lab, Argonne, IL 60439 USA.;[Barnby, L. S.; Burton, T. P.; Gaillard, L.; Jones, P. G.; Nelson, J. M.; Timmins, A. R.] Univ Birmingham, Birmingham, W Midlands, England.;[Bland, L. C.; Bravar, A.; Christie, W.; DePhillips, M.; Didenko, L.; Dunlop, J. C.; Fachini, P.; Fine, V.; Fisyak, Y.; Hallman, T. J.; Landgraf, J. M.; Laue, F.; Lauret, J.; Lebedev, A.; LeVine, M. J.; Ljubicic, T.; Longacre, R. S.; Love, W. A.; Ludlam, T.; Lynn, D.; Ogawa, A.; Panitkin, S. Y.; Perevoztchikov, V.; Potekhin, M.; Sorensen, P.; Tang, A. H.; Ullrich, T.; Van Buren, G.; Xu, Z.; Zhang, H.] Brookhaven Natl Lab, Upton, NY 11973 USA.;[Hughes, E. W.; Relyea, D.] CALTECH, Pasadena, CA 91125 USA.;[Crawford, H. J.; Engelage, J.; Judd, E. G.; Perkins, C.] 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.
作者机构:
[Mohanty, B.] Bhabha Atom Res Ctr, Ctr Variable Energy Cyclotron, Kolkata 700064, W Bengal, India.;Argonne Natl Lab, Argonne, IL 60439 USA.;Univ Birmingham, Birmingham B15 2TT, W Midlands, England.;Brookhaven Natl Lab, Upton, NY 11973 USA.;CALTECH, Pasadena, CA 91125 USA.
通讯机构:
[Mohanty, B.] B;Bhabha Atom Res Ctr, Ctr Variable Energy Cyclotron, Kolkata 700064, W Bengal, India.
关键词:
particle production;perturbative quantum chromodynamics;fragmentation function;Cronin effect and x(T)-scating
摘要:
We present the transverse momentum (PT) spectra for identified charged pions, protons and anti-protons from p + p and d + Au collisions at root sNN = 200 GeV. The spectra are measured around midrapidity (vertical bar y vertical bar < 0.5) over the range of 0.3 < PT < 10 GeV/c with particle identification from the ionization energy loss and its relativistic rise in the time projection chamber and time-of-flight in STAR. The charged pion and proton + anti-proton spectra at high PT in p + p and d + Au collisions are in good agreement with a phenomenological model (EPOS) and with next-to-leading order perturbative quantum chromodynamic (NLO pQCD) calculations with a specific fragmentation scheme and factorization scale. We found that all proton, anti-proton and charged pion spectra in p + p collisions follow x(T)-scating for the momentum range where particle production is dominated by hard processes (p(T) greater than or similar to 2 GeV/c). The nuclear modification factor around midrapidity is found to be greater than unity for charged pions and to be even larger for protons at 2 < PT < 5 GeV/c. (c) 2006 Elsevier B.V. All rights reserved.
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.