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27 results on '"Subrata Pal"'

1. Constraining the relativistic mean-field model equations of state with gravitational wave observations

Author

Prasanta Char, Rana Nandi, and Subrata Pal

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Solar mass, Equation of state, Nuclear Theory, 010308 nuclear & particles physics, Gravitational wave, Star (game theory), FOS: Physical sciences, Radius, 01 natural sciences, Nuclear Theory (nucl-th), Theoretical physics, Neutron star, Mean field theory, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Nuclear Experiment, 010306 general physics, Astrophysics::Galaxy Astrophysics, Energy (signal processing)
Abstract

The first detection of gravitational waves from the binary neutron star merger event GW170817 has started to provide important new constraints on the nuclear equation of state at high density. The tidal deformability bound of GW170817 combined with the observed two solar mass neutron star poses a serious challenge to theoretical formulations of realistic equations of state. We analyze a fully comprehensive set of relativistic nuclear mean-field theories by confronting them with the observational bounds and the measured neutron-skin thickness. We find that only a few models can withstand these bounds which predict a stiff overall equation of state but with a soft neutron-proton symmetry energy. Two possible indications are proposed: Circumstantial evidence of hadron-quark phase transition inside the star and new parametrizations that are consistent with ground state properties of finite nuclei and observational bounds. Based on extensive analysis of these sets, an upper limit on the radius of a $1.4M_\odot$ neutron star of $R_{1.4}\lesssim 12.9$ km is deduced., Matches with the published version

Published
2019

2. Collective flow in event-by-event partonic transport plus hydrodynamics hybrid approach

Author

Amaresh Jaiswal, Subrata Pal, and Rajeev S. Bhalerao

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Hadron, FOS: Physical sciences, Parton, Nuclear Theory (nucl-th), Nuclear physics, symbols.namesake, Distribution function, Boltzmann constant, Quark–gluon plasma, symbols, Production (computer science), Nuclear Experiment, Nucleon, Relativistic Heavy Ion Collider
Abstract

Complete evolution of the strongly interacting matter formed in ultrarelativistic heavy-ion collisions is studied within a coupled Boltzmann and relativistic viscous hydrodynamics approach. For the initial nonequilibrium evolution phase, we employ the AMPT model that explicitly includes event-by-event fluctuations in the number and positions of the participating nucleons as well as of the produced partons with subsequent parton transport. The ensuing near-equilibrium evolution of quark-gluon and hadronic matter is modeled within the (2+1)-dimensional viscous hydrodynamics. We probe the role of parton dynamics in generating and maintaining the spatial anisotropy in the preequilibrium phase. Substantial eccentricities epsilon_n are found to be generated in the event-by-event fluctuations in parton production from initial nucleon-nucleon collisions. For ultracentral heavy-ion collisions, the model is able to explain qualitatively the unexpected hierarchy of the harmonic flow coefficients v_n(p_T)(n=2-6) observed at LHC. We find that the results for v_n(p_T) are rather insensitive to the variation (within a range) of the time of switchover from AMPT parton transport to hydrodynamic evolution. The usual Grad and the recently proposed Chapman-Enskog-like (nonequilibrium) single-particle distribution functions are found to give very similar results for v_n(n=2-4). The model describes well both the RHIC and LHC data for v_n(p_T) at various centralities, with a constant shear viscosity to entropy density ratio of 0.08 and 0.12, respectively. The event-by-event distributions of v_{2,3} are in good agreement with the LHC data for midcentral collisions. The linear response relation v_n = k_n epsilon_n is found to be true for n=2,3, except at large values of epsilon_n, where a larger value of k_n is required, suggesting a small admixture of positive nonlinear response even for n=2,3., 8 pages, 9 figures, v2: Same as the published version. Title changed

Published
2015

3. Relativistic third-order viscous corrections to the entropy four-current from kinetic theory

Author

Radoslaw Ryblewski, Chandrodoy Chattopadhyay, Amaresh Jaiswal, and Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, Configuration entropy, FOS: Physical sciences, Four-current, Parton, Entropy of mixing, Boltzmann equation, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Computer Science::Graphics, Classical mechanics, Exact solutions in general relativity, Boltzmann's entropy formula, Entropy (arrow of time), Mathematical physics
Abstract

By employing a Chapman-Enskog like iterative solution of the Boltzmann equation in relaxation-time approximation, we derive a new expression for the entropy four-current up to third order in gradient expansion. We show that unlike second-order and third-order entropy four-current obtained using Grad's method, there is a non-vanishing entropy flux in the present third-order expression. We further quantify the effect of the higher-order entropy density in the case of boost-invariant one-dimensional longitudinal expansion of a system. We demonstrate that the results obtained using third-order evolution equation for shear stress tensor, derived by employing the method of Chapman-Enskog expansion, show better agreement with the exact solution of the Boltzmann equation as well as with the parton cascade BAMPS, as compared to those obtained using the third-order equations from the method of Grad's 14-moment approximation., 8 pages, 8 figures, published version

Published
2015

4. Multiplicity scaling in nuclear fragmentation

Author

Sandip Samaddar, Subrata Pal, B. Djerroud, and J. N. De

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Fragmentation (mass spectrometry), Multiplicity (chemistry), Scaling
Published
1998

6. Complete relativistic second-order dissipative hydrodynamics from the entropy principle

Author

Subrata Pal, Rajeev S. Bhalerao, and Amaresh Jaiswal

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, media_common.quotation_subject, FOS: Physical sciences, Second law of thermodynamics, Volume viscosity, Lattice QCD, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Classical mechanics, Distribution function, Cavitation, Dissipative system, Statistical physics, Entropy (arrow of time), Scaling, media_common
Abstract

We present a new derivation of relativistic dissipative hydrodynamic equations, which invokes the second law of thermodynamics for the entropy four-current expressed in terms of the single-particle phase-space distribution function obtained from Grad's 14-moment approximation. This derivation is complete in the sense that all the second-order transport coefficients are uniquely determined within a single theoretical framework. In particular, this removes the long-standing ambiguity in the relaxation time for bulk viscosity thereby eliminating one of the uncertainties in the extraction of the shear viscosity to entropy density ratio from confrontation with the anisotropic flow data in relativistic heavy-ion collisions. We find that in the one-dimensional scaling expansion, these transport coefficients prevent the occurrence of cavitation even for rather large values of the bulk viscosity estimated in lattice QCD., 5 pages, 2 figures, version to appear in PRC (Rapid Comm)

Published
2013

7. Low-mass dilepton production in a relativistic Hagedorn-resonance gas model

Author

Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Meson, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Resonance, Spectral line, Nuclear physics, Quark–gluon plasma, Mass spectrum, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, Low Mass
Abstract

Dilepton production in the low-invariant-mass region in p+p and Au + Au collisions at sNN=200 GeV and in Pb + Au collisions at 158 AGeV is studied in the relativistic hadron resonance gas model with Hagedorn mass spectrum that grows exponentially. The model provides good agreement with the observed yield and spectra of stable hadrons and resonances produced in both p+p and nucleus-nucleus collisions. While the measured dilepton yields in p+p collisions are well understood in the model with Dalitz and direct decays of conventional neutral meson sources, a sizable amount of the mesons produced from the Hagedorn states still cannot explain the large enhancement observed in the invariant mass region 200–700 MeV/c2 in Pb + Au and especially in Au + Au collisions. In a multiphase transport (AMPT) model, the dilepton produced from the standard hadronic sources in absence of Hagedorn states underpredicts the data to a larger extent. The study suggests that Hagedorn states in conjugation with in-medium modification of the properties of ρ mesons may be essential for the enhanced dilepton production.

Published
2012

8. Role of isospin physics in supernova matter and neutron stars

Author

B. K. Sharma and Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, FOS: Physical sciences, Astrophysics, Nuclear matter, Asymmetry, Nuclear Theory (nucl-th), Nuclear physics, Supernova, Stars, Neutron star, Neutron, Neutrino, Nuclear Experiment, Astrophysics::Galaxy Astrophysics, media_common
Abstract

We investigate the liquid-gas phase transition of hot protoneutron stars shortly after their birth following supernova explosion and the composition and structure of hyperon-rich (proto)neutron stars within a relativistic mean-field model where the nuclear symmetry energy has been constrained from the measured neutron skin thickness of finite nuclei. Light clusters are abundantly formed with increasing temperature well inside the neutrino-sphere for an uniform supernova matter. Liquid-gas phase transition is found to suppress the cluster yield within the coexistence phase as well as decrease considerably the neutron-proton asymmetry over a wide density range. We find symmetry energy has a modest effect on the boundaries and the critical temperature for the liquid-gas phase transition, and the composition depends more sensitively on the number of trapped neutrinos and temperature of the protoneutron star. The influence of hyperons in the dense interior of stars makes the overall equation of state soft. However, neutrino trapping distinctly delays the appearance of hyperons due to abundance of electrons. We also find that a softer symmetry energy further makes the onset of hyperon less favorable. The resulting structures of the (proto)neutron stars with hyperons and with liquid-gas phase transition are discussed., Comment: 11 pages, 7 figures, RevTex

Published
2010

9. Nuclear symmetry energy effects on liquid-gas phase transition in hot asymmetric nuclear matter

Author

Subrata Pal and B. K. Sharma

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, Condensed matter physics, Critical phenomena, media_common.quotation_subject, FOS: Physical sciences, Nuclear matter, Asymmetry, Symmetry (physics), Nuclear Theory (nucl-th), Nuclear physics, Isospin, Neutron, Nuclear Experiment, Nucleon, media_common
Abstract

The liquid-gas phase transition in hot asymmetric nuclear matter is investigated within relativistic mean-field model using the density dependence of nuclear symmetry energy constrained from the measured neutron skin thickness of finite nuclei. We find symmetry energy has a significant influence on several features of liquid-gas phase transition. The boundary and area of the liquid-gas coexistence region, the maximal isospin asymmetry and the critical values of pressure and isospin asymmetry all of which systematically increase with increasing softness in the density dependence of symmetry energy. The critical temperature below which the liquid-gas mixed phase exists is found higher for a softer symmetry energy., 5 pages, RevTex, 5 figures

Published
2010

10. Observation of charge-dependent azimuthal correlations and possible local strong parity violation in heavy-ion collisions

Author

L. H. Tarini, M. DePhillips, G. Eppley, I. Bnzarov, G. Van Buren, Michal Sumbera, Xu Cai, Hank Crawford, J. Pluta, S. S. Shi, T. S. McShane, J. Engelage, T. W. Ludlam, L. K. Mangotra, S. W. Wissink, A. Ridiger, J. M. Nelson, S. Baumgart, R. S. Longacre, Nikola Poljak, A. Geromitsos, Matthew Walker, J. H. Thomas, K. Kajimoto, Saskia Mioduszewski, Premomoy Ghosh, M. Zawisza, H. M. Spinka, D. Kettler, R. Manweiler, Hongfang Liu, Jongmin Lee, Yan Li, Jing-Han Chen, W. Peryt, R. E. Tribble, R. L. Ray, J. M. Landgraf, G. S. Averichev, S. Kabana, Y. P. Viyogi, T. J. Humanic, L. Kotchenda, Gerald W Hoffmann, Debasish Das, Raghunath Sahoo, B. Haag, C. A. Whitten, Feng Jin, M. Strikhanov, S. Heppelmann, A. Chikanian, J. L. Drachenberg, D. Staszak, Qian Yue, R. Varma, A. M. Poskanzer, V. N. Tram, J. Ulery, A. Lebedev, O. Catu, I. Sakrejda, M. Heinz, Lee Stuart Barnby, Yu A. Matulenko, B. S. Page, J. Konzer, G. Igo, L. Ruan, Anju Bhasin, H. Caines, Ki-Seok Choi, R. Corliss, R. Fatemi, Michael Joseph Betancourt, D. P. Kikola, B. Stringfellow, E. Hjort, Y. Fisyak, S. Bueltmann, Zebo Tang, J. Bouchet, S. Zhang, J. Sandweiss, Jana Bielcikova, B. E. Bonner, B. Erazmus, R. P. Redwine, K. Kauder, D. Arkhipkin, A. Hamed, Z. Chajecki, A. Feng, H. G. Ritter, Y. F. Wu, Christine Nattrass, T. Ljubicic, Subhasis Chattopadhyay, Andrew Rose, I. K. Yoo, J. X. Zuo, O. Barannikova, R. Bellwied, Y. Zhao, D. D. Koetke, L. G. Efimov, Y. Yang, K. Kang, S. J. Lindenbaum, X. R. Wang, K. Krueger, J. G. Cramer, V. Ghazikhanian, Jay Roberts, S. LaPointe, A. Kechechyan, Andre Mischke, M. Krus, N. Li, A. Kocoloski, Jaroslav Bielcik, J. A. Vanfossen, Neeraj Gupta, Haiyan Wang, D. Cebra, Russell Richard Betts, A. Iordanova, R. Cendejas, S. Dash, A. Bridgeman, A. Gordon, L. C. Bland, Z. J. Sun, Q. H. Xu, D. R. Gangadharan, E. G. Judd, S. Trentalange, J. L. Romero, S. M. Guertin, M. Estienne, Alexandre Alarcon Do Passo Suaide, C. Perkins, D. Thein, G. Wang, T. Peitzmann, M. Sharma, B. D. Anderson, R. N. Singaraju, L. Huo, A. P. Meschanin, P. Seyboth, E. J. Garcia-Solis, O. D. Tsai, Elena Bruna, Sudhir Raniwala, J. W. Harris, Z. Xu, G. Lin, Sergei A. Voloshin, N. G. Minaev, D. P. Mahapatra, R. S. Hollis, E. Finch, H. Bichsel, Anik Gupta, R. Derradi de Souza, B. I. Abelev, N. K. Pruthi, G. Odyniec, Y. Zoulkarneeva, M. Kopytine, P. Sorensen, X. H. Shi, M. R. Dutta Mazumdar, K. Yip, L. Liu, C. L. Jones, Bedangadas Mohanty, J. S. Wang, Jianping Cheng, M. Cherney, M. Elnimr, Basanta Kumar Nandi, J. E. Draper, M. J. Skoby, Frank Jm Geurts, J. C. Dunlop, M. C. Suarez, M. J. M. Codrington, H. Z. Huang, S. Vokal, Thomas Michael Cormier, E. Elhalhuli, Lokesh Kumar, Peter Graham Jones, P. Yepes, Yifu Sun, Zubayer Ahammed, I. Koralt, B. Biritz, Jifa Tian, V. A. Okorokov, M. C. Cervantes, A. H. Tang, O. V. Rogachevskiy, P. R. Pujahari, M. J. LeVine, T. D. S. Stanislaus, F. Videbæk, G. Webb, C. Roy, H. H. Wieman, Q. Wang, David Jonathan Hofman, T. P. Burton, M. J. Russcher, P. Chung, D. G. Underwood, E. P. Sichtermann, J. Kiryluk, Yannis K. Semertzidis, L. V. Nogach, M. J. Ng, M. Wada, J. Joseph, D. A. Morozov, Mikhail Tokarev, H. Masui, G. M.S. Vasconcelos, M. S. Daugherity, Jorn Henning Putschke, M. S. Ganti, J. Seele, Y. Pandit, A. V. Brandin, L. Didenko, J. Balewski, Rashmi Raniwala, R. Milner, H. Okada, W. Christie, V. I. Kravtsov, P. Chaloupka, N. Schmitz, P. Fachini, W. Xie, E. Shahaliev, Chitrasen Jena, Claude Andre Pruneau, H. F. Chen, Y. P. Lu, V. Perevoztchikov, F. Liu, X. Zhu, Ermes Braidot, G. Van Nieuwenhuizen, Peter Martin Jacobs, Xiang Sun, W. A. Love, Adam Ryszard Kisiel, Jing Zhou, Guo-Liang Ma, William Axel Leight, T. Ullrich, J. Takahashi, A. S. Hirsch, J. C. Webb, Mateusz Andrzej Ploskon, R. Witt, Marcelo Gameiro Munhoz, D. J. Prindle, P. Kravtsov, R. Zoulkarneev, P. Kurnadi, S. B. Nurushev, S. R. Klein, R. D. Majka, L. Eun, N. L. Subba, V. Yu Khodyrev, Donika Plyku, D. L. Olson, Subrata Pal, Donald M. McDonald, M. A. Lisa, Zhenyu Zhang, J. Sowinski, J. Y. Chen, S. Margetis, R. F. Clarke, J. Schambach, X. L. Wang, C. Zhong, B. K. Srivastava, M. R. Cosentino, Sevil Salur, Y. Wang, M. Shao, X. Dong, Madan M. Aggarwal, Fuqiang Wang, A. A. Derevschikov, W. M. Zhang, Andrey Vasiliev, T. J. Hallman, Y. Panebratsev, Janet Elizabeth Seger, T. J. M. Symons, A. M. Hoffman, F. Benedosso, Yong Xu, D. Grosnick, V. Kouchpil, K. S.F.F. Guimaraes, V. Dzhordzhadze, L. C. De Silva, Yi Zhang, W. L. Zhan, Rolf K. Reed, Frank Simon, T. G. Dedovich, T. Sakuma, S. C. Phatak, I. Selyuzhenkov, A. Szanto de Toledo, J. Kapitan, V. Fine, A. R. Timmins, S. M. Dogra, Bernd Surrow, T. Pawlak, A. K. Bhati, D. Keane, Nikolai Smirnov, Xiaoping Zhang, A. V. Alakhverdyants, C-H. Lee, T. K. Nayak, Pawan Kumar Netrakanti, B. Grube, W. Guryn, O. G. Grebenyuk, J. Fedorisin, C. A. Gagliardi, A. G. Knospe, M. Pachr, W. J. Llope, Jie Liu, Hanna Paulina Zbroszczyk, D. R. Beavis, M. Calderón De La Barca Sánchez, O. I. Mall, M. A.C. Lamont, B. V.K.S. Potukuchi, Yu-Gang Ma, N. Xu, P. Filip, C-Q. Li, S. Sakai, P. Pile, G. D. Westfall, R. P. Scharenberg, Christina Markert, Petr Jákl, H. S. Matis, W. W. Jacobs, J. Lauret, R. Lednicky, T. Tarnowsky, P. Djawotho, Sergey Timoshenko, Wolfgang Korsch, A. Ogawa, D. Tlusty, Mirko Planinic, Y. N. Gorbunov, Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), and STAR

Subjects
Quark, Nuclear and High Energy Physics, Particle physics, dependence rapidity dependence transverse momentum, Star, Nuclear Theory, Vacuum, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], dependence 62, FOS: Physical sciences, Relativistic Nuclear Collisions, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], scattering gold copper quantum chromodynamics, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, angular correlation topological Monte Carlo STAR Brookhaven RHIC Coll impact parameter, 0103 physical sciences, 11.30.Er, 11.30.Qc, 25.75.Ld, 25.75.Nq, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Physics, Quantum chromodynamics, Matter, 010308 nuclear & particles physics, Elliptic flow, Parity (physics), Observable, Fermion, Collaboration, NATURAL SCIENCES. Physics, PRIRODNE ZNANOSTI. Fizika, parity, Elliptic Flow, violation heavy ion, Time Projection Chamber, Perspective, Quark–gluon plasma, 200 GeV-cms/nucleon, Quark-Gluon Plasma, (3particle) charged particle, Hot Qcd, vacuum state correlation function, STAR detector
Abstract

Parity-odd domains, corresponding to non-trivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the orbital momentum of the system created in non-central collisions. To study this effect, we investigate a three particle mixed harmonics azimuthal correlator which is a \P-even observable, but directly sensitive to the charge separation effect. We report measurements of this observable using the STAR detector in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}$=200 and 62~GeV. The results are presented as a function of collision centrality, particle separation in rapidity, and particle transverse momentum. A signal consistent with several of the theoretical expectations is detected in all four data sets. We compare our results to the predictions of existing event generators, and discuss in detail possible contributions from other effects that are not related to parity violation., Comment: 17 pages, 14 figures, as accepted for publication in Physical Review C.

Published
2010

11. Identified particle production, azimuthal anisotropy, and interferometry measurements inAu+Aucollisions atsNN=9.2GeV

Author

G. Lin, P. Kurnadi, P. Djawotho, M. Heinz, Lee Stuart Barnby, J. E. Draper, M. J. Skoby, Frank Jm Geurts, E. Elhalhuli, Jifa Tian, J. Engelage, F. Benedosso, A. G. Knospe, Jaroslav Bielcik, T. G. Dedovich, A. Geromitsos, William Jacobs, Premomoy Ghosh, J. M. Landgraf, C-Q. Li, M. R. Dutta Mazumdar, T. Sakuma, S. C. Phatak, V. Fine, Russell Richard Betts, M. Strikhanov, Y. Xu, O. V. Rogachevskiy, R. P. Scharenberg, Christina Markert, M. K. Mitrovski, Shoko Sakai, H. S. Matis, H. Masui, Zhibing Li, Jake Y. Chen, E. Hjort, Y. F. Wu, D. G. Underwood, A. Ridiger, Christine Nattrass, B. Haag, J. Konzer, L. Didenko, J. C. Dunlop, K. Yip, K. Kang, K. Kajimoto, Saskia Mioduszewski, Mikhail Tokarev, W. A. Love, Zebo Tang, H. Caines, Ki-Seok Choi, M. Zawisza, H. M. Spinka, L. Xue, J. Lauret, Zubayer Ahammed, J. S. Wang, R. R. Debbe, Y. Wang, Thomas Humanic, E. P. Sichtermann, Y. Zoulkarneeva, C. Zhong, T. S. McShane, R. Lednicky, M. J. LeVine, J. M. Joseph, J. H. Thomas, G. Odyniec, J. Sandweiss, Z. Chajecki, D. D. Koetke, D. Kettler, J. Balewski, Madan M. Aggarwal, N. Xu, S. Timoshenko, Fuqiang Wang, P. Filip, L. Kotchenda, Q. Wang, M. J. Russcher, G. S. Averichev, J. Ulery, Rashmi Raniwala, I. Koralt, T. R. Schuster, C. Perkins, Ilya Selyuzhenkov, J. M. Rehberg, R. S. Longacre, H. G. Ritter, H. Z. Huang, L. H. Tarini, Sergei A. Voloshin, J. C. Webb, T. Peitzmann, J. L. Drachenberg, S. Zhang, L. V. Nogach, M. J. Ng, V. I. Kravtsov, P. Pile, G. D. Westfall, Claude Andre Pruneau, Sadhana Dash, O. Barannikova, R. Bellwied, I. Bnzarov, T. J. Hallman, E. G. Judd, G. J. van Nieuwenhuizen, T. J. M. Symons, Anthony Robert Timmins, C. L. Jones, S. Baumgart, Jing Zhou, Matthew Walker, Mirko Planinic, Jay Roberts, D. Thein, Adam Ryszard Kisiel, I. Sakrejda, Marcelo Gameiro Munhoz, D. J. Prindle, D. Tlusty, W. L. Zhan, S. Vokal, Y. Fisyak, A. Gupta, Petr Jákl, T. Ullrich, L. C. De Silva, Frank Simon, D. R. Gangadharan, Donika Plyku, P. Chung, S. M. Guertin, William Axel Leight, X. Zhu, S. R. Klein, T. Tarnowsky, N. L. Subba, M. A. Lisa, Debasish Das, Raghunath Sahoo, M. A.C. Lamont, Mateusz Andrzej Ploskon, R. Witt, R. Zoulkarneev, Vitaly Okorokov, R. Fatemi, Michael Joseph Betancourt, D. P. Mahapatra, M. Kopytine, D. L. Olson, L. C. Bland, Bernd Surrow, J. Kiryluk, J. H. Chen, Yifu Sun, W. Zhou, Y. P. Viyogi, Y. Yang, V. Yu Khodyrev, S. LaPointe, N. Li, Wei Xie, R. S. Hollis, Subrata Pal, Donald M. McDonald, L. Eun, A. A. Derevschikov, G. Igo, B. K. Srivastava, D. A. Morozov, G. M.S. Vasconcelos, X. L. Wang, K. Krueger, M. C. Suarez, C. A. Whitten, Feng Jin, Pawan Kumar Netrakanti, J. A. Vanfossen, J. Bouchet, A. Szanto de Toledo, B. Erazmus, J. Kapitan, L. Ruan, G. Wang, Qian Yue, A. V. Brandin, H. Okada, C. A. Gagliardi, K. Kauder, W. Xu, S. Margetis, R. Corliss, M. Pachr, T. D. S. Stanislaus, X. Dong, Y. Pandit, George Stephans, T. Pawlak, Y. Zhao, R. Varma, A. Rose, James Prewitt Hays-Wehle, Yu A. Matulenko, B. S. Page, Neeraj Gupta, D. Cebra, M. Estienne, A. V. Alakhverdyants, X. Lin, Z. J. Sun, H. H. Wieman, S. J. Lindenbaum, N. Schmitz, B. Grube, Q. H. Xu, Jongmin Lee, D. P. Kikola, L. K. Mangotra, R. L. Ray, P. Seyboth, B. Stringfellow, D. Staszak, R. N. Singaraju, E. Shahaliev, L. Huo, A. P. Meschanin, R. Manweiler, W. Guryn, R. Derradi de Souza, B. I. Abelev, T. Ljubicic, O. G. Grebenyuk, Jianping Cheng, Sudhir Raniwala, B. D. Anderson, J. Fedorisin, V. Ghazikhanian, J. G. Cramer, M. J. M. Codrington, M. Cherney, A. Kechechyan, Andre Mischke, Lokesh Kumar, M. Krus, R. Cendejas, Jana Bielcikova, Prabhat Ranjan Pujahari, J. L. Romero, M. Sharma, N. K. Pruthi, N. G. Minaev, E. Finch, G. Eppley, Xu Cai, J. Pluta, Jie Liu, Y. H. Zhu, Gerald W Hoffmann, J. Seele, Hanna Paulina Zbroszczyk, D. R. Beavis, J. W. Harris, R. Reed, P. Yepes, A. H. Tang, W. M. Zhang, Andrey Vasiliev, O. I. Mall, L-X. Han, M. Calderon De La Barca Sanchez, O. Catu, A. Kocoloski, P. G. Jones, Yu-Gang Ma, A. Hirsch, W. J. Llope, Janet Elizabeth Seger, A. M. Hoffman, Y. Li, T. Kollegger, F. Liu, Edmundo Javier Garcia-Solis, Ascelin Gordon, R. D. Majka, J. Sowinski, R. F. Clarke, J. Schambach, L. G. Efimov, Anju Bhasin, R. P. Redwine, Haiyan Wang, A. Lebedev, X. M. Sun, P. Sorensen, M. Shao, G. Van Buren, S. S. Shi, T. W. Ludlam, J. M. Nelson, W. Peryt, P. Fachini, Peter Martin Jacobs, D. J. Hofman, J. Takahashi, S. B. Nurushev, Bedangadas Mohanty, R. G. Fersch, M. Wada, Robert E. Tribble, I. K. Yoo, M. DePhillips, Michal Sumbera, A. A. P. Suaide, Hank Crawford, S. W. Wissink, Y. Zhang, Nikola Poljak, Y. N. Gorbunov, B. V. K. S. Potukuchi, Wolfgang Korsch, A. Bridgeman, J. Putschke, A. Ogawa, H. F. Chen, Thomas A. Trainor, Basanta Kumar Nandi, B. Biritz, A. M. Poskanzer, T. P. Burton, C. Roy, P. Chaloupka, B. E. Bonner, O. D. Tsai, S. Kabana, S. Trentalange, M. Elnimr, M. C. Cervantes, H. Liu, V. N. Tram, R. Milner, D. Arkhipkin, A. Hamed, Sevil Salur, E. Braidot, A. Iordanova, A. K. Bhati, D. Keane, R. Stock, Xiaoping Zhang, C-H. Lee, T. K. Nayak, Y. Panebratsev, D. Grosnick, V. Kouchpil, Z. Z. Xu, Samuel Heppelmann, Nikita Smirnov, Guo-Liang Ma, A. Chikanian, Z. P. Zhang, P. Kravtsov, F. Videbæk, G. Webb, M. S. Ganti, H. Bichsel, W. Christie, Chitrasen Jena, Y. P. Lu, V. Perevoztchikov, Sunil Dogra, S. Bueltmann, Subhasis Chattopadhyay, and Elena Bruna

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Time projection chamber, Meson, 010308 nuclear & particles physics, Nuclear Theory, Elliptic flow, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Quark–gluon plasma, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, 010306 general physics, STAR detector
Abstract

We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from Au + Au collisions below the nominal injection energy at the BNL Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance solenoidal tracker at RHIC (STAR) detector at root s(NN) = 9.2 GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density dN/dy in rapidity y, average transverse momentum , particle ratios, elliptic flow, and Hanbury-Brown-Twiss (HBT) radii are consistent with the corresponding results at similar root s(NN) from fixed-target experiments. Directed flow measurements are presented for both midrapidity and forward-rapidity regions. Furthermore the collision centrality dependence of identified particle dN/dy, , and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for root s(NN) = 200 GeV, are suitable for the proposed QCD critical-point search and exploration of the QCD phase diagram at RHIC.

Published
2010

12. Long range rapidity correlations and jet production in high energy nuclear collisions

Author

M. DePhillips, Michal Sumbera, Hank Crawford, B. E. Bonner, P. R. Pujahari, S. W. Wissink, B. Haag, Nikola Poljak, L. Kotchenda, Bedangadas Mohanty, J. Lauret, O. D. Tsai, S. Kabana, B. Srivastava, M. Wada, M. Bystersky, L. C. Bland, F. Videbæk, T. P. Burton, N. Schmitz, M. Elnimr, I. K. Yoo, M. C. Cervantes, G. Webb, D. R. Gangadharan, Marcelo Gameiro Munhoz, D. J. Prindle, Zebo Tang, D. Thein, R. Milner, A. Shabetai, Debasish Das, A. Ridiger, Jongmin Lee, M. Heinz, Lee Stuart Barnby, A. H. Tang, K. Kang, Xiang Sun, R. L. Ray, B. Grube, M. Kopytine, Jie Liu, K. Kajimoto, E. G. Judd, Jaroslav Bielcik, Raghunath Sahoo, Hanna Paulina Zbroszczyk, M. A.C. Lamont, G. Igo, Mikhail Tokarev, S. Heppelmann, J. G. Cramer, Donika Plyku, Z. Chajecki, Sevil Salur, Y. Wang, M. A. Lisa, W. Guryn, William Axel Leight, L. Liu, C. L. Jones, D. R. Beavis, P. Filip, J. Bouchet, C. Perkins, M. R. Dutta Mazumdar, I. Sakrejda, M. S. Ganti, Z. J. Sun, H. Bichsel, M. C. Suarez, V. Fine, S. R. Klein, William Jacobs, N. L. Subba, J. Engelage, O. V. Rogachevskiy, T. Peitzmann, K. Kauder, Congbo Li, D. L. Olson, T. D. S. Stanislaus, A. Geromitsos, Premomoy Ghosh, D. Staszak, H. H. Wieman, J. X. Zuo, O. G. Grebenyuk, D. D. Koetke, S. Sakai, S. M. Guertin, G. Lin, P. Pile, W. A. Love, W. Christie, A. K. Bhati, D. Keane, Sudhir Raniwala, T. S. McShane, Anik Gupta, Alexandre Alarcon Do Passo Suaide, A. A. Derevschikov, D. Tlusty, J. Fedorisin, Nikolai Smirnov, Petr Jákl, L. V. Nogach, Y. Zoulkarneeva, Xiaoping Zhang, Ermes Braidot, Y. Yang, S. LaPointe, N. Li, D. P. Mahapatra, R. S. Hollis, Andrew Rose, Chitrasen Jena, Y. Zhao, Madan M. Aggarwal, Christine Nattrass, L. K. Mangotra, R. Manweiler, Hongfang Liu, O. I. Mall, Wei Xie, S. B. Nurushev, Sergei A. Voloshin, Mirko Planinic, A. G. Knospe, A. Gordon, S. Baumgart, C-H. Lee, T. K. Nayak, Fuqiang Wang, J. E. Draper, E. Shahaliev, Jorn Henning Putschke, M. Zawisza, P. Sorensen, X. H. Shi, Y. P. Lu, A. V. Brandin, M. J. Skoby, Frank Jm Geurts, L. G. Efimov, E. Elhalhuli, J. Konzer, Yong Xu, V. Perevoztchikov, B. D. Anderson, H. Okada, J. Joseph, G. M.S. Vasconcelos, Adam Ryszard Kisiel, Matthew Walker, S. E. Vigdor, J. Baudot, Jifa Tian, E. P. Sichtermann, Y. Panebratsev, D. Grosnick, V. Kouchpil, H. Caines, N. K. Pruthi, A. Kechechyan, Andre Mischke, Ki-Seok Choi, P. G. Jones, Christian Claude Kuhn, C. A. Whitten, Feng Jin, S. Vokal, Q. Wang, Yifu Sun, Christina Markert, Q. H. Xu, G. Eppley, J. Seger, R. Corliss, M. Krus, Y. Pandit, L. Didenko, R. Cendejas, Y. N. Gorbunov, Haiyan Wang, Jana Bielcikova, A. Szanto de Toledo, B. Erazmus, S. J. Lindenbaum, B. V.K.S. Potukuchi, Yi Zhang, Xu Cai, W. L. Zhan, J. Pluta, J. H. Thomas, M. J. Russcher, J. Kapitan, T. Ullrich, R. Fatemi, Michael Joseph Betancourt, H. G. Ritter, Y. P. Viyogi, Guo-Liang Ma, A. R. Timmins, S. M. Dogra, Y. Fisyak, M. S. Daugherity, Yu-Gang Ma, A. Hirsch, Rolf K. Reed, P. Kurnadi, Frank Simon, J. Balewski, Rashmi Raniwala, K. Yip, J. S. Wang, A. Chikanian, K. Krueger, A. Ogawa, Zhenyu Zhang, W. J. Llope, M. Sharma, R. N. Singaraju, L. Huo, A. P. Meschanin, T. Pawlak, M. R. Cosentino, J. A. Vanfossen, Claude Andre Pruneau, J. Sandweiss, R. E. Tribble, Gerald W Hoffmann, I. Selyuzhenkov, A. V. Alakhverdyants, J. C. Webb, J. Kiryluk, Sergey Timoshenko, P. Kravtsov, D. Kettler, F. Benedosso, W. He, Russell Richard Betts, Bernd Surrow, G. Wang, R. Zoulkarneev, M. Cherney, K. S.F.F. Guimaraes, Wolfgang Korsch, B. Stringfellow, Thomas Michael Cormier, E. Hjort, D. G. Underwood, G. S. Averichev, Lokesh Kumar, D. A. Morozov, P. Seyboth, E. J. Garcia-Solis, J. Sowinski, Lijuan Ruan, M. Sarsour, Gary Westfall, A. M. Poskanzer, Jing Zhou, Thomas Humanic, L. H. Tarini, L. Eun, R. Derradi de Souza, B. I. Abelev, S. Bueltmann, T. G. Dedovich, Pawan Kumar Netrakanti, M. Shao, Subhasis Chattopadhyay, T. J. Hallman, T. J. M. Symons, J. Ulery, T. Sakuma, Xuan Wang, T. Ljubicic, Jianping Cheng, Thomas A. Trainor, G. Odyniec, S. C. Phatak, L. C. De Silva, X. L. Wang, H. M. Spinka, C. Zhong, I. Bnzarov, S. S. Shi, Elena Bruna, H. Z. Huang, R. P. Scharenberg, C. A. Gagliardi, G. Van Buren, M. J. M. Codrington, X. Dong, H. S. Matis, M. Pachr, Neeraj Gupta, D. Cebra, V. Ghazikhanian, S. Trentalange, O. Barannikova, R. Bellwied, M. Estienne, V. N. Tram, I. Koralt, M. J. Ng, Marek Bombara, L. Gaillard, R. Lednicky, P. Djawotho, Zhongbin Xu, V. I. Kravtsov, G. Van Nieuwenhuizen, D. Arkhipkin, A. Hamed, E. Finch, A. Iordanova, T. W. Ludlam, Anju Bhasin, R. P. Redwine, J. M. Nelson, Yuanfang Wu, Yan Li, Jing-Han Chen, Basanta Kumar Nandi, W. Peryt, R. S. Longacre, T. Tarnowsky, B. Biritz, David Jonathan Hofman, H. Masui, V. A. Okorokov, P. Fachini, C. Roy, J. M. Landgraf, Peter Martin Jacobs, J. Takahashi, P. Chaloupka, S. Margetis, H. F. Chen, W. M. Zhang, Andrey Vasiliev, Nu Xu, A. M. Hoffman, F. Liu, J. L. Drachenberg, S. Zhang, M. Strikhanov, R. D. Majka, J. L. Romero, A. Feng, J. Y. Chen, R. F. Clarke, Jay Roberts, X. Zhu, Mateusz Andrzej Ploskon, R. Witt, S. Mioduszewski, V. Yu Khodyrev, Subrata Pal, Donald M. McDonald, Boris Hippolyte, J. C. Dunlop, Qian Yue, R. Varma, Yu A. Matulenko, B. S. Page, D. P. Kikola, Zubayer Ahammed, M. J. LeVine, M. Calderon De La Barca Sanchez, A. Lebedev, O. Catu, J. Schambach, A. Kocoloski, S. Dash, N. G. Minaev, J. W. Harris, and P. Yepes

Subjects
Nuclear and High Energy Physics, di-hadron, Hadron, FOS: Physical sciences, 01 natural sciences, Spectral line, Nuclear physics, correlations, 0103 physical sciences, Rapidity, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Physics, Jet (fluid), Range (particle radiation), 010308 nuclear & particles physics, Collaboration, NATURAL SCIENCES. Physics, PRIRODNE ZNANOSTI. Fizika, Deuterium, Perspective, Quark–gluon plasma, Quark-Gluon Plasma, High Energy Physics::Experiment, Atomic physics, Relativistic Heavy Ion Collider
Abstract

The STAR Collaboration at RHIC presents a systematic study of high transverse momentum charged di-hadron correlations at small azimuthal pair separation \dphino, in d+Au and central Au+Au collisions at $\rts = 200$ GeV. Significant correlated yield for pairs with large longitudinal separation \deta is observed in central Au+Au, in contrast to d+Au collisions. The associated yield distribution in \detano$\times$\dphi can be decomposed into a narrow jet-like peak at small angular separation which has a similar shape to that found in d+Au collisions, and a component which is narrow in \dphi and \textcolor{black}{depends only weakly on} $\deta$, the "ridge". Using two systematically independent analyses, \textcolor{black}{finite ridge yield} is found to persist for trigger $\pt > 6$ \GeVc, indicating that it is correlated with jet production. The transverse momentum spectrum of hadrons comprising the ridge is found to be similar to that of bulk particle production in the measured range ($2 < \pt < 4 \GeVc$)., Submitted to Phys. Rev. C, 9 pages, 6 figures

Published
2009

13. Systematic measurements of identified particle spectra inpp,d+Au, andAu+Aucollisions at the STAR detector

Author

R. Manweiler, Hongfang Liu, H. Z. Huang, S. Vokal, A. M. Poskanzer, J. Engelage, J. Kiryluk, A. Kechechyan, Andre Mischke, M. Krus, R. Cendejas, D. A. Morozov, M. Heinz, Premomoy Ghosh, David Jonathan Hofman, J. M. Landgraf, O. I. Mall, Ermes Braidot, M. Calderon De La Barca Sanchez, O. Catu, Adam Ryszard Kisiel, J. S. Wang, M. Strikhanov, B. Haag, Zebo Tang, B. V.K.S. Potukuchi, H. J. Crawford, H. Bichsel, G. Odyniec, Y. Zoulkarneeva, D. Thein, M. Kopytine, M. Tokarev, T. D. S. Stanislaus, A. Kocoloski, S. Dash, A. Ridiger, H. Caines, Ki-Seok Choi, S. Heppelmann, J. Sandweiss, D. D. Koetke, J. E. Draper, F. Videbæk, M. S. Ganti, Y. P. Lu, Sergei A. Voloshin, V. Perevoztchikov, J. P. Coffin, B. E. Bonner, O. D. Tsai, W. Christie, M. Elnimr, W. M. Zhang, M. C. Cervantes, Andrey Vasiliev, Sevil Salur, A. Stadnik, Peter Martin Jacobs, J. Takahashi, S. B. Nurushev, M. Sharma, V. Fine, Z. Chajecki, C. Perkins, X. L. Wang, C. Zhong, David Lynn, Q. Wang, M. J. Russcher, M. van Leeuwen, X. Dong, H. H. Wieman, M. DePhillips, Michal Sumbera, D. Tlusty, Mirko Planinic, R. Fatemi, Y. Bai, S. W. Wissink, Y. Zhang, Nikola Poljak, Y. N. Gorbunov, L. C. Bland, Yu-Gang Ma, Janet Elizabeth Seger, N. G. Minaev, H. Zhang, K. Krueger, J. A. Vanfossen, S. S. Shi, A. M. Hoffman, Thomas Peitzmann, I. Selyuzhenkov, Z. Xu, G. Lin, J. W. Harris, Anthony R. Timmins, Jing Zhou, W. J. Llope, Sergey Timoshenko, K. Kang, R. L. Ray, D. Staszak, L. Kotchenda, J. Callner, W. He, M. Cherney, Thomas Michael Cormier, P. Yepes, S. Bueltmann, A. H. Tang, I. Sakrejda, Lokesh Kumar, J. H. Thomas, T. Ljubicic, F. Du, M. Sarsour, M. J. Skoby, C. A. Whitten, Feng Jin, A. Chikanian, V. N. Tram, E. Elhalhuli, Rama Narayana Singaraju, J. X. Zuo, Jifa Tian, V. Rykov, T. P. Burton, Bedangadas Mohanty, L. Liu, B. Erazmus, Bernd Surrow, Sudhir Raniwala, W. T. Waggoner, L. V. Nogach, M. J. Ng, M. C. Suarez, E. P. Sichtermann, Pawan Kumar Netrakanti, Jana Bielcikova, Morton Kaplan, S. J. Lindenbaum, F. Liu, Chang-Hwan Lee, Raimond Snellings, L. K. Mangotra, V. I. Kravtsov, P. Djawotho, A. P. Meschanin, J. Balewski, Rashmi Raniwala, Neeraj Gupta, D. Cebra, D. Arkhipkin, A. Hamed, N. Xu, P. Filip, S. LaPointe, Claude Andre Pruneau, Jie Liu, S. Trentalange, Xiangming Sun, G. D. Westfall, C. A. Gagliardi, P. Kurnadi, A. Gordon, M. Estienne, Y. Panebratsev, G. Van Buren, A. Iordanova, R. D. Majka, Petr Jákl, T. Ullrich, Xuan Wang, Zhenyu Zhang, C. Nepali, Hanna Paulina Zbroszczyk, Jorn Henning Putschke, M. Botje, A. Szanto de Toledo, A. Ogawa, R. Zoulkarneev, D. Grosnick, J. Y. Chen, V. Kouchpil, S. Margetis, R. F. Clarke, J. Schambach, Lee Stuart Barnby, H. F. Chen, M. R. Cosentino, J. Kapitan, D. Kettler, D. R. Beavis, W. R. Edwards, Anju Bhasin, A. V. Brandin, S. U. Chung, M. Wada, T. W. Ludlam, H. Okada, L. Eun, Jaroslav Bielcik, S. M. Dogra, C-Q. Li, Marcelo Gameiro Munhoz, D. J. Prindle, J. M. Nelson, S. Q. Zhang, F. Benedosso, A. Lebedev, S. E. Vigdor, J. H. Chen, M. Bystersky, Yan Li, W. Peryt, Christian Claude Kuhn, R. P. Scharenberg, Christina Markert, Yuanfang Wu, M. R. Dutta Mazumdar, T. Pawlak, O. V. Rogachevskiy, M. A. Lisa, H. S. Matis, Basanta Kumar Nandi, T. G. Dedovich, G. S. Averichev, W. A. Love, X. Lin, T. Sakuma, B. Biritz, R. S. Longacre, S. C. Phatak, V. A. Okorokov, W. W. Jacobs, S. M. Guertin, B. Grube, Alexandre Alarcon Do Passo Suaide, Madan M. Aggarwal, Fuqiang Wang, C. Roy, Yong Xu, C. De Silva, J. Lauret, W. Guryn, P. Chaloupka, Debasish Das, Raghunath Sahoo, Frank Simon, O. G. Grebenyuk, Rolf K. Reed, R. Lednicky, L. Molnar, M. A.C. Lamont, J. Fedorisin, K. Kajimoto, G. Igo, D. P. Mahapatra, B. D. Anderson, A. G. Knospe, Russell Richard Betts, D. G. Underwood, Lijuan Ruan, J. Bouchet, M. S. Daugherity, M. Shao, T. J. Hallman, J. Cheng, T. J. M. Symons, R. S. Hollis, J. Millane, I. K. Yoo, Andrew Rose, Y. Zhao, N. K. Pruthi, M. Zawisza, H. M. Spinka, G. Eppley, Xu Cai, J. Pluta, D. R. Gangadharan, E. G. Judd, J. Ulery, H. G. Ritter, O. Barannikova, R. Bellwied, L. Gaillard, M. Pachr, R. E. Tribble, V. Emelianov, A. K. Bhati, D. Keane, Gerald W Hoffmann, Nikolai Smirnov, J. Mitchell, L. G. Efimov, T. K. Nayak, Christine Nattrass, Subhasis Chattopadhyay, M. L. Miller, Elena Bruna, Guo-Liang Ma, A. S. Hirsch, J. C. Webb, P. Kravtsov, J. Sowinski, G. Wang, P. Seyboth, E. J. Garcia-Solis, R. Witt, R. Derradi de Souza, B. I. Abelev, S. Mioduszewski, V. Yu Khodyrev, J. Baudot, W. Zhan, Yanchu Wang, Subrata Pal, B. K. Srivastava, I. M. Vasilevski, M. J. M. Codrington, A. Gupta, S. Bhardwaj, Boris Hippolyte, A. Shabetai, T. S. McShane, J. C. Dunlop, Q. H. Xu, Zubayer Ahammed, Z. J. Sun, M. J. LeVine, J. Joseph, G. M.S. Vasconcelos, Y. Pandit, S. Baumgart, N. Schmitz, E. Shahaliev, J. L. Drachenberg, V. Ghazikhanian, A. Feng, Marek Bombara, J. L. Romero, Jay Roberts, Y. Fisyak, E. Finch, A. M. Vander Molen, E. Hjort, Thomas Humanic, P. Sorensen, Y. J. Sun, X. H. Shi, Peter Graham Jones, L. Didenko, S. Kabana, Y. P. Viyogi, S. R. Klein, T. Tarnowsky, N. L. Subba, D. L. Olson, A. A. Derevschikov, A. L. Trattner, J. G. Cramer, P. Fachini, K. S.F.F. Guimaraes, Qian Yue, R. Varma, Yu A. Matulenko, B. S. Page, and B. Stringfellow

Subjects
Elastic scattering, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Strangeness production, Strangeness, Kinetic energy, 01 natural sciences, 7. Clean energy, Charged particle, Hadronization, Nuclear physics, Baryon, 13. Climate action, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider
Abstract

Identified charged-particle spectra of pi(+/-), K(+/-), p, and (p) over bar at midrapidity (vertical bar y vertical bar < 0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d + Au collisions at root s(NN) = 200 GeV and for Au + Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm(3) for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase-transition temperature, suggesting that chemical freeze-out happens in the vicinity of hadronization and the chemical freeze-out temperature is universal despite the vastly different initial conditions in the collision systems. The extracted kinetic freeze-out temperature, while similar to the chemical freeze-out temperature in pp, d + Au, and peripheral Au + Au collisions, drops significantly with centrality in Au + Au collisions, whereas the extracted transverse radial flow velocity increases rapidly with centrality. There appears to be a prolonged period of particle elastic scatterings from chemical to kinetic freeze-out in central Au + Au collisions. The bulk properties extracted at chemical and kinetic freeze-out are observed to evolve smoothly over the measured energy range, collision systems, and collision centralities.

Published
2009

14. Resonance production in relativistic heavy ion collisions in a binary emission model

Author

Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, Resonance, Elastic collision, Nuclear physics, Baryon, Yield (chemistry), Quark–gluon plasma, Atomic physics, Nuclear Experiment, Relativistic Heavy Ion Collider
Abstract

Resonance particle ratios and spectra are calculated in the sequential binary emission model for hadrons produced from the decay of a single massive resonance formed in relativistic heavy ion collisions. The sequential model which is quite successful in reproducing the yield ratios for stable hadrons at energies currently available at the BNL Relativistic Heavy Ion Collider (RHIC) is found to describe remarkably well the yield ratios for the resonances K*(892){sup 0} and {phi} mesons. The model indicates a short expansion time between the average chemical and thermal freeze-out with negligible regeneration of the resonances via the inverse two-body elastic collision process. Model estimates of the yield ratios for the strange baryons {lambda}(1520) and {sigma}(1385) are presented.

Published
2008

15. Spin alignment measurements of theK*0(892)andϕ(1020)vector mesons in heavy ion collisions atsNN=200GeV

Author

Zhenyu Zhang, M. R. Cosentino, F. Benedosso, V. Fine, Jake Y. Chen, T. G. Dedovich, T. Sakuma, S. C. Phatak, F. Du, V. Rykov, L. V. Nogach, M. J. Ng, V. I. Kravtsov, H. Zhang, I. Sakrejda, J. X. Zuo, David Jonathan Hofman, Kyungeon Choi, L. Kotchenda, A. M. Vander Molen, A. Stadnik, R. S. Longacre, S. LaPointe, A. Gordon, Peter Martin Jacobs, G. Eppley, Y. F. Wu, Xu Cai, Gang Wang, J. Takahashi, Debasish Das, Raghunath Sahoo, J. Pluta, S. B. Nurushev, M. A.C. Lamont, G. Igo, D. Thein, T. P. Burton, J. Bouchet, J. Millane, P. Djawotho, M. Pachr, R. E. Tribble, Andrew Rose, Y. Zhao, Gerald W Hoffmann, Morton Kaplan, S. M. Guertin, M. Sharma, M. Kopytine, Alexandre Alarcon Do Passo Suaide, J. S. Wang, R. N. Singaraju, A. P. Meschanin, Raimond Snellings, N. G. Minaev, D. P. Mahapatra, G. Van Buren, Mikhail Tokarev, Xiangming Sun, R. S. Hollis, S. S. Shi, T. W. Ludlam, J. G. Cramer, J. M. Nelson, C. Nepali, Yinina Ma, T. D. S. Stanislaus, Jorn Henning Putschke, B. D. Anderson, A. V. Brandin, Yan Li, H. Okada, W. Peryt, V. Ghazikhanian, H. H. Wieman, W. Christie, N. K. Pruthi, S. E. Vigdor, C. A. Whitten, Marek Bombara, Christian Claude Kuhn, L. K. Mangotra, W. M. Zhang, Andrey Vasiliev, Adam Ryszard Kisiel, J. L. Romero, H. J. Crawford, R. Manweiler, Xiaoyu Wang, F. Laue, Shaobo Zhang, A. Chikanian, M. J. Skoby, S. Lange, E. Finch, R. Fatemi, Jana Bielcikova, Christine Nattrass, V. N. Tram, A. Szanto de Toledo, A. M. Poskanzer, J. L. Drachenberg, K. Krueger, S. J. Lindenbaum, Q. H. Xu, H. Z. Huang, S. Vokal, K. Kajimoto, J. Kapitan, S. M. Dogra, N. Xu, P. Filip, Z. J. Sun, Janet Elizabeth Seger, Thomas Peitzmann, P. Sorensen, G. D. Westfall, D. Arkhipkin, A. Hamed, Peter Graham Jones, A. M. Hoffman, A. Kechechyan, Andre Mischke, G. M.S. Vasconcelos, J. Callner, W. He, T. Pawlak, Petr Jákl, N. Gupta, A. Feng, T. J. Humanic, M. Cherney, Thomas Michael Cormier, Lokesh Kumar, J. W. Harris, R. Cendejas, N. Schmitz, Akash Kumar, E. Shahaliev, A. Iordanova, M. Sarsour, X. Lin, J. Kiryluk, Pijush Ghosh, L. Didenko, X-H. Shi, N. T. Porile, Jay Roberts, P. Seyboth, E. J. Garcia-Solis, C. Roy, Anthony R. Timmins, Qian Yue, D. A. Morozov, B. Grube, J. Baudot, M. Wada, F. Liu, P. Yepes, A. Ridiger, S. Bueltmann, A. H. Tang, Thorsten Sven Kollegger, R. Varma, Yu A. Matulenko, S. Heppelmann, W. Guryn, R. Derradi de Souza, B. I. Abelev, B. Haag, P. Chaloupka, D. D. Koetke, J. E. Draper, B. Stringfellow, S. R. Klein, O. G. Grebenyuk, T. Tarnowsky, N. L. Subba, D. L. Olson, Zebo Tang, J. Fedorisin, Sergei A. Voloshin, J. P. Coffin, Hong Liu, A. G. Knospe, T. S. McShane, Russell Richard Betts, I. A. Qattan, Z. Chajecki, M. J. M. Codrington, D. G. Underwood, Lijuan Ruan, A. A. Derevschikov, S. Baumgart, A. L. Trattner, R. D. Majka, C. Perkins, J. C. Dunlop, Z. Xu, G. Lin, M. Shao, S. Margetis, R. F. Clarke, J. Schambach, Anju Bhasin, T. J. Hallman, J. Cheng, T. J. M. Symons, Sergey Timoshenko, Jianhong Wu, Basanta Kumar Nandi, S. Kabana, J. Tian, E. Elhalhuli, I. Selyuzhenkov, Y. P. Viyogi, Zubayer Ahammed, M. J. LeVine, A. Lebedev, Vitaly Okorokov, M. M. de Moura, B. Biritz, M. Botje, Y. Fisyak, Bernd Surrow, W. T. Waggoner, P. Fachini, M. Calderon De La Barca Sanchez, K. S.F.F. Guimaraes, Pawan Kumar Netrakanti, O. Catu, C. A. Gagliardi, N. van der Kolk, A. Ogawa, A. Kocoloski, Madan M. Aggarwal, H. F. Chen, S. Dash, Thomas A. Trainor, W. R. Edwards, Fuqiang Wang, C-Q. Li, R. Witt, R. P. Scharenberg, Christina Markert, S. Mioduszewski, W. L. Zhan, H. S. Matis, V. Yu Khodyrev, Frank Simon, Subrata Pal, M. Heinz, Lee Stuart Barnby, Jaroslav Bielcik, B. K. Srivastava, I. M. Vasilevski, W. W. Jacobs, J. Lauret, M. R. Dutta Mazumdar, A. Gupta, S. Bhardwaj, Boris Hippolyte, O. V. Rogachevskiy, R. Lednicky, W. A. Love, Y. Panebratsev, D. Grosnick, V. Kouchpil, T. Dietel, B. E. Bonner, Mirko Planinic, O. D. Tsai, M. Elnimr, M. C. Cervantes, Sevil Salur, Y. Wang, V. Emelianov, A. K. Bhati, D. Keane, Y. N. Gorbunov, Nikolai Smirnov, R. Stock, J. Mitchell, L. G. Efimov, C-H. Lee, T. K. Nayak, J. Ulery, H. G. Ritter, Bedangadas Mohanty, O. Barannikova, R. Bellwied, L. Gaillard, M. S. Daugherity, L. C. Bland, L. Liu, M. C. Suarez, J. H. Chen, M. Bystersky, F. Videbæk, Sukalyan Chattopadhyay, M. DePhillips, Michal Sumbera, M. S. Ganti, Y. Bai, S. W. Wissink, Y. Zhang, Nikola Poljak, V. Perevoztchikov, E. W. Hughes, I. K. Yoo, Alexandre Shabetai, M. L. Miller, Y. Lu, D. R. Gangadharan, E. G. Judd, Guo-Liang Ma, A. S. Hirsch, J. C. Webb, P. Kravtsov, J. Sowinski, J. Engelage, J. M. Landgraf, M. Strikhanov, J. Sandweiss, K. Kang, B. V.K.S. Potukuchi, Jie Liu, Hanna Paulina Zbroszczyk, D. R. Beavis, X. L. Wang, C. Zhong, M. van Leeuwen, X. Dong, F. Jin, W. J. Llope, R. L. Ray, D. Staszak, J. H. Thomas, T. Ljubicic, H. Caines, Sudhir Raniwala, E. P. Sichtermann, J. Balewski, Rashmi Raniwala, Claude Andre Pruneau, D. Kettler, T. Ullrich, R. Zoulkarneev, L. Eun, G. S. Averichev, M. Zawisza, H. M. Spinka, H. Bichsel, G. Odyniec, Y. Zoulkarneeva, M. Potekhin, David Lynn, Q. Wang, M. J. Russcher, J. G. Ma, Jing Zhou, B. Erazmus, D. Cebra, S. Trentalange, M. Estienne, S. U. Chung, Marcelo Gameiro Munhoz, D. J. Prindle, M. A. Lisa, E. Braidot, and P. Kurnadi

Subjects
Physics, Density matrix, Nuclear and High Energy Physics, Angular momentum, Meson, Magnetic moment, Spins, 010308 nuclear & particles physics, Polarization (waves), 01 natural sciences, Nuclear physics, 0103 physical sciences, Quark–gluon plasma, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy
Abstract

We present the first spin alignment measurements for the K*{sup 0}(892) and (1020) vector mesons produced at midrapidity with transverse momenta up to 5 GeV/c at {radical}s{sub NN} = 200 GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in Au+Au collisions are {rho}{sub 00} = 0.32 {+-} 0.04 (stat) {+-} 0.09 (syst) for the K*{sup 0} (0.8 < p{sub T} < 5.0 GeV/c) and {rho}{sub 00} = 0.34 {+-} 0.02 (stat) {+-} 0.03 (syst) for the {phi} (0.4 < p{sub T} < 5.0 GeV/c) and are constant with transverse momentum and collision centrality. The data are consistent with the unpolarized expectation of 1/3 and thus no evidence is found for the transfer of the orbital angular momentum of the colliding system to the vector-meson spins. Spin alignments for K*{sup 0} and {phi} in Au+Au collisions were also measured with respect to the particle's production plane. The {phi} result, {rho}{sub 00} = 0.41 {+-} 0.02 (stat) {+-} 0.04 (syst), is consistent with that in p+p collisions, {rho}{sub 00} = 0.39 {+-} 0.03 (stat) {+-} 0.06 (syst), also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamicsmore » of vector mesons.« less

Published
2008

16. Forward Λ production and nuclear stopping power ind+Aucollisions atsNN=200GeV

Author

T. S. McShane, F. Laue, A. Szanto de Toledo, B. Erazmus, J. Kapitan, S. M. Dogra, P. Kurnadi, S. Baumgart, L. Kotchenda, M. S. Ganti, H. Bichsel, Zhenyu Zhang, Reinhard Stock, T. Pawlak, T. Dietel, M. R. Cosentino, Mirko Planinic, Vitaly Okorokov, W. Christie, K. Kang, T. P. Burton, F. Benedosso, Saskia Mioduszewski, X. Lin, V. Perevoztchikov, Bernd Surrow, X. L. Wang, E. W. Hughes, V. V. Belaga, J. Speltz, P. Sorensen, S. R. Klein, Jichao Wang, T. Tarnowsky, N. L. Subba, K. L. Kowalik, Y. N. Gorbunov, L. Didenko, L. K. Mangotra, D. L. Olson, C. Zhong, Y. P. Viyogi, A. A. Derevschikov, J. Engelage, M. DePhillips, R. Manweiler, B. Grube, P. G. Jones, A. N. Zubarev, S. M. Guertin, Alexandre Alarcon Do Passo Suaide, M. Zawisza, H. M. Spinka, V. Ghazikhanian, M. van Leeuwen, X. Dong, A. M. Poskanzer, Pawan Kumar Netrakanti, T. G. Dedovich, K. S.F.F. Guimaraes, J. Ulery, J. W. Harris, C-Q. Li, David Jonathan Hofman, T. Sakuma, Marcelo Gameiro Munhoz, D. J. Prindle, H. G. Ritter, R. P. Scharenberg, Christina Markert, H. Z. Huang, Subhasis Chattopadhyay, B. V.K.S. Potukuchi, Anju Bhasin, A. Bravar, M. Sharma, Michal Sumbera, J. L. Drachenberg, Yu-Gang Ma, A. Hirsch, S. C. Phatak, H. S. Matis, Premomoy Ghosh, J. M. Landgraf, D. P. Mahapatra, R. S. Hollis, O. Barannikova, William Jacobs, R. Bellwied, J. H. Thomas, A. Kechechyan, Andre Mischke, E. M. Kislov, J. G. Cramer, L. Gaillard, L. C. Bland, C. A. Gagliardi, M. L. Miller, P. Fachini, A. Stadnik, Anthony R. Timmins, Hank Crawford, N. G. Minaev, Marek Bombara, V. Fine, J. Lauret, A. Lebedev, N. van der Kolk, M. Strikhanov, Yuanfang Wu, R. Lednicky, Peter Martin Jacobs, M. A. Lisa, L. Ruan, A. A. Kuznetsov, Xiangming Sun, L. Liu, N. Gupta, Christine Nattrass, O. G. Grebenyuk, Y. Bai, R. L. Ray, J. L. Romero, E. Potrebenikova, D. Kettler, M. J. M. Codrington, M. M. de Moura, I-K. Yoo, S. L. Blyth, A. Feng, H. Caines, Y. Lu, P. Yepes, V. Eckardt, M. C. Suarez, Renaud Vernet, P. Filip, V. B. Dunin, Basanta Kumar Nandi, D. Staszak, Madan M. Aggarwal, Fuqiang Wang, Sergey Timoshenko, Guo-Liang Ma, J. Fedorisin, M. Kopytine, J. Fu, A. Chikanian, S. W. Wissink, J. Sandweiss, S. B. Nurushev, Jay Roberts, R. Snellings, G. Odyniec, N. K. Pruthi, Y. Zoulkarneeva, G. D. Westfall, I. Selyuzhenkov, T. Ljubicic, G. S. Averichev, M. Oldenburg, P. S. Sazhin, C. Roy, E. Finch, Z. Xu, G. Lin, M. Potekhin, P. Djawotho, A. G. Knospe, Russell Richard Betts, J. Baudot, W. Zhan, Sudhir Raniwala, Q. Yue, J. Takahashi, B. D. Anderson, J. C. Webb, P. Kravtsov, G. Van Buren, M. S. Daugherity, Nikola Poljak, David Lynn, D. G. Underwood, S. S. Shimanskiy, Petr Jákl, W. J. Llope, D. Relyea, A. Ogawa, E. P. Sichtermann, N. T. Porile, T. D. S. Stanislaus, Y. Li, M. J. Russcher, H. F. Chen, Thomas A. Trainor, W. R. Edwards, H. Gos, P. Chaloupka, H. H. Wieman, G. Eppley, T. W. Ludlam, J. Sowinski, Xu Cai, M. J. Horner, J. Pluta, A. I. Kulikov, A. Kumar, V. I. Yurevich, R. Varma, Yufeng Zhang, J. Balewski, Rashmi Raniwala, W. M. Zhang, Andrey Vasiliev, M. Shao, J. Callner, Yu A. Matulenko, J. M. Nelson, A. H. Tang, H. Liu, M. Botje, J. E. Draper, Claude Andre Pruneau, T. J. Hallman, T. J. M. Symons, F. Du, Nu Xu, R. Witt, J. G. Ma, W. Peryt, Janet Elizabeth Seger, D. Arkhipkin, Bedangadas Mohanty, A. Hamed, S. U. Chung, Wen-Qing Shen, B. Stringfellow, Frank Simon, A. M. Hoffman, M. Pachr, A. Iordanova, V. Yu Khodyrev, Subrata Pal, L. V. Nogach, T. Ullrich, A. I. Pavlinov, B. K. Srivastava, I. M. Vasilevski, Gerald W Hoffmann, F. Liu, R. Zoulkarneev, L. G. Efimov, M. Calderon De La Barca Sanchez, M. Heinz, Lee Stuart Barnby, J. Liu, O. Catu, C. A. Whitten, V. I. Kravtsov, Jaroslav Bielcik, R. D. Majka, S. Bhardwaj, Boris Hippolyte, D. Cebra, J. C. Dunlop, J. H. Chen, A. Kocoloski, M. Bystersky, Q. Li, S. Trentalange, S. Dash, J. Y. Chen, M. Estienne, S. Margetis, R. F. Clarke, J. Schambach, Yu Melnick, Morton Kaplan, M. R. Dutta Mazumdar, Robert E. Tribble, Zubayer Ahammed, M. J. LeVine, F. Jia, S. Lange, N. Schmitz, O. V. Rogachevskiy, Jana Bielcikova, S. J. Lindenbaum, E. Shahaliev, W. A. Love, Alexandre Shabetai, W. T. Waggoner, A. M. Vander Molen, B. Haag, E. Hjort, Y. Wang, I. A. Qattan, Z. Chajecki, C. Perkins, Thomas Humanic, B. E. Bonner, O. D. Tsai, S. Kabana, M. C. Cervantes, R. Fatemi, Sevil Salur, K. Krueger, Q. H. Xu, Thomas Peitzmann, Y. Panebratsev, D. Grosnick, V. Kouchpil, M. Wada, Z. J. Sun, W. He, M. Cherney, Thomas Michael Cormier, M. Sarsour, Samuel Heppelmann, Mikhail Tokarev, E. Garcia-Solis, R. N. Singaraju, A. P. Meschanin, J. Zhou, Adam Ryszard Kisiel, R. S. Longacre, S. Vokal, Debasish Das, Raghunath Sahoo, M. A.C. Lamont, A. Bellingeri-Laurikainen, G. Igo, V. Emelianov, A. K. Bhati, D. Keane, J. Bouchet, Y. Fisyak, J. Millane, Andrew Rose, Y. Zhao, Nikolai Smirnov, J. Mitchell, J. Kiryluk, H. Zhang, E. G. Judd, D. A. Morozov, S. Lehocka, I. Sakrejda, C-H. Lee, T. K. Nayak, A. Ridiger, Thorsten Sven Kollegger, J. X. Zuo, G. Wang, J. Wu, P. Seyboth, L. Martin, S. LaPointe, D. D. Koetke, C. J. McClain, C. Nepali, Jorn Henning Putschke, B. I. Abelev, A. V. Brandin, Sergei A. Voloshin, J. P. Coffin, Jianping Cheng, T. W. Henry, S. E. Vigdor, and Christian Claude Kuhn

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Hadron, Lambda, 01 natural sciences, 7. Clean energy, Asymmetry, Particle identification, Nuclear physics, Baryon, 0103 physical sciences, Stopping power (particle radiation), Nuclear Experiment, 010306 general physics, Nucleon, Relativistic Heavy Ion Collider, media_common
Abstract

We report the measurement of {lambda} and {lambda} yields and inverse slope parameters in d+Au collisions at {radical}(s{sub NN})=200 GeV at forward and backward rapidities (y={+-}2.75), using data from the STAR forward time projection chambers. The contributions of different processes to baryon transport and particle production are probed exploiting the inherent asymmetry of the d+Au system. Comparisons to model calculations show that baryon transport on the deuteron side is consistent with multiple collisions of the deuteron nucleons with gold participants. On the gold side, HIJING-based models without a hadronic rescattering phase do not describe the measured particle yields, while models that include target remnants or hadronic rescattering do. The multichain model can provide a good description of the net baryon density in d+Au collisions at energies currently available at the BNL Relativistic Heavy Ion Collider, and the derived parameters of the model agree with those from nuclear collisions at lower energies.

Published
2007

17. Minijet deformation and charge-independent angular correlations on momentum subspace(η,ϕ)in Au-Au collisions atsNN=130GeV

Author

O. D. Tsai, Vitaly Okorokov, T. S. McShane, E. Sugarbaker, Y. Panebratsev, D. Grosnick, V. Kouchpil, C. Roy, S. Vokal, Sevil Salur, Y. Wang, A. Tai, J. Amonett, Bernd Surrow, R. S. Longacre, V. Emelianov, A. K. Bhati, D. Keane, Nikolai Smirnov, B. Erazmus, J. Mitchell, L. G. Efimov, C-H. Lee, T. K. Nayak, L. K. Mangotra, R. Manweiler, G. Eppley, Debasish Das, Raghunath Sahoo, I. K. Yoo, Y. G. Gorbunov, M. S. Daugherity, M. A.C. Lamont, A. Stolpovsky, Pawan Kumar Netrakanti, A. Bellingeri-Laurikainen, Hao-Ze Chen, L. Kotchenda, S. Hepplemann, Xu Cai, J. Pluta, S. V. Razin, J. Kiryluk, G. Igo, P. Seyboth, H. M. Liu, WL Zhan, A. M. Poskanzer, D. Cebra, M. Swanger, M. Calderon De La Barca Sanchez, Sergey Voloshin, Christine Nattrass, S. Trentalange, H. Gos, P. Chaloupka, J. Bouchet, O. Catu, M. Estienne, A. I. Pavlinov, F. Liu, E. G. Judd, B. Haag, Yu Melnick, C. A. Gagliardi, N. van der Kolk, A. Kechechyan, Andre Mischke, J. H. Thomas, D. A. Morozov, Andrew Rose, K. Schweda, Y. Zhao, G. Sood, N. Schmitz, E. Shahaliev, H. Bichsel, G. Odyniec, Y. Zoulkarneeva, Q. Li, J. E. Gonzalez, C. O. Blyth, Q. H. Xu, Jianping Cheng, C-Q. Li, Jay Roberts, K. Kang, A. H. Tang, M. Pachr, R. E. Tribble, L. C. Bland, A. Chikanian, M. Potekhin, Zhijia Sun, A. A. Kuznetsov, David Lynn, S. Kabana, Y. P. Viyogi, Bedangadas Mohanty, A. M. Vander Molen, L. Liu, M. J. Russcher, T. D. Gutierrez, R. D. Majka, X. L. Wang, C. Zhong, B. I. Bezverkhny, Gerald W Hoffmann, M. Botje, I. Sakrejda, P. Fachini, D. K. Mishra, E. Hjort, J. Baudot, A. Ridiger, Thorsten Sven Kollegger, R. P. Scharenberg, Gregory Rakness, R. N. Singaraju, A. P. Meschanin, E. M. Kislov, J. C. Webb, A. Stadnik, J. G. Cramer, S. M. Guertin, Alexandre Alarcon Do Passo Suaide, D. Arkhipkin, A. Kumar, D. Thein, S. Margetis, J. Schambach, Y. Guo, L. Ruan, M. J. Horner, M. van Leeuwen, X. Dong, W. Christie, S. Bekele, J. X. Zuo, J. Adams, Peter Martin Jacobs, A. Hamed, Wen-Qing Shen, V. Ghazikhanian, O. G. Grebenyuk, H. S. Matis, F. Du, J. G. Ma, M. Lopez-Noriega, M. Kopytine, J. Fu, V. B. Dunin, A. Ishihara, A. I. Kulikov, J. H. Chen, M. Bystersky, J. L. Romero, D. P. Mahapatra, W. M. Zhang, J. Wu, Yu Chen, J. Fedorisin, A. Bravar, Z. Chajecki, Gang Wang, Y. Lu, Marcelo Gameiro Munhoz, D. J. Prindle, Adam Ryszard Kisiel, H. Jiang, Andrey Vasiliev, P. S. Sazhin, E. Finch, M. Tokarev, J. Speltz, C. F. Moore, Nu Xu, M. Shao, M. DePhillips, J. Ulery, L. Martin, J. W. Harris, E. P. Sichtermann, L. V. Nogach, D. Magestro, R. Snellings, H. J. Crawford, H. G. Ritter, M. A. Lisa, Basanta Kumar Nandi, J. Porter, W. J. Dong, J. Balewski, S. LaPointe, Rashmi Raniwala, B. D. Anderson, C. Perkins, D. D. Koetke, Janet Elizabeth Seger, Michal Sumbera, S. B. Nurushev, Anthony R. Timmins, Claude Andre Pruneau, R. Bellwied, R. Fatemi, G. S. Averichev, P. Yepes, V. Eckardt, T. D. S. Stanislaus, Renaud Vernet, Yinina Ma, H. A. Choi, H. H. Wieman, M. Sharma, V. I. Kravtsov, J. Engelage, L. Gaillard, W. W. Jacobs, J. E. Draper, C. J. McClain, Anju Bhasin, K. Krueger, C. Mironov, T. Ullrich, John N. Wood, J. C. Dunlop, Y. Fisyak, Z. Xu, G. Lin, R. Zoulkarneev, Zhenyu Zhang, Reinhard Stock, M. R. Cosentino, Zubayer Ahammed, Premomoy Ghosh, Thomas Peitzmann, R. Picha, Anik Gupta, F. Retiere, Y. Bai, M. J. LeVine, S. Lehocka, J. Castillo, M. Kramer, J. M. Landgraf, J. P. Coffin, A. Lebedev, R. V. Cadman, W. He, J. Lauret, M. Cherney, Thomas Michael Cormier, M. Strikhanov, F. Jia, S. W. Wissink, Y. Zhang, R. L. Ray, E. Potrebenikova, M. Sarsour, T. J. Humanic, S. L. Blyth, T. G. Dedovich, M. M. de Moura, S. C. Phatak, H. Z. Huang, Christina Markert, J. Sandweiss, Z. Liu, Nikola Poljak, N. T. Porile, V. Fine, Beomkyu Kim, F. Laue, A. Szanto de Toledo, J. Kapitan, T. Ljubicic, R. Varma, W. T. Waggoner, Jian-Song Wang, Yu A. Matulenko, H. Caines, Sudhir Raniwala, B. Stringfellow, A. Shabetai, S. S. Shimanskiy, D. Relyea, Souvik Das, S. M. Dogra, A. Wetzler, R. Witt, N. G. Minaev, Morton Kaplan, S. Mioduszewski, V. Yu Khodyrev, Subrata Pal, S. Bharadwaj, B. K. Srivastava, I. M. Vasilevski, J. Gans, Boris Hippolyte, I. Selyuzhenkov, H. M. Spinka, R. Lednicky, L. Molnar, J. Reinnarth, T. Pawlak, G. Van Buren, T. W. Ludlam, J. M. Nelson, Yan Li, W. Peryt, Jorn Henning Putschke, A. V. Brandin, H. Zhang, S. E. Vigdor, Christian Claude Kuhn, Sergey Timoshenko, D. G. Underwood, P. Filip, Matthew J. Anderson, T. J. Hallman, T. J. M. Symons, J. Takahashi, J. W. Watson, A. Ogawa, Shengli Huang, Thomas A. Trainor, W. R. Edwards, T. Dietel, Mirko Planinic, G. D. Westfall, T. W. Henry, Petr Jákl, A. N. Zubarev, K. S.F.F. Guimaraes, V. V. Belaga, P. Sorensen, C. A. Whitten, S. Lange, Jana Bielcikova, S. J. Lindenbaum, Peter Graham Jones, L. Didenko, S. R. Klein, T. Tarnowsky, O. Barannikova, D. L. Olson, A. A. Derevschikov, Madan M. Aggarwal, Fuqiang Wang, M. Oldenburg, V. I. Yurevich, Frank Simon, M. Heinz, Lee Stuart Barnby, Jaroslav Bielcik, M. R. Dutta Mazumdar, O. V. Rogachevskiy, W. A. Love, Sukalyan Chattopadhyay, M. S. Ganti, V. Perevoztchikov, K. Filimonov, E. W. Hughes, K. L. Kowalik, Sergey Panitkin, M. L. Miller, Guo-Liang Ma, A. S. Hirsch, P. Kravtsov, Jeffrey G. Reid, J. Sowinski, V. A. Nikitin, B. V.K.S. Potukuchi, Vladimir Petrov, W. J. Llope, H. Long, Jie Liu, P. Djawotho, and B. E. Bonner

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Hadron, Elliptic flow, Parton, 01 natural sciences, Nuclear physics, Azimuth, Amplitude, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract

Measurements of two-particle correlations on angular difference variables η1 − η2 (pseudorapidity) and φ1 − φ2 (azimuth) are presented for all primary charged hadrons with transverse momentum 0.15 ≤ p_t ≤ 2 GeV/c and |η| ≤ 1.3 from Au-Au collisions at √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 π/2 or greater than π/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 η1 − η2 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.

Published
2006

18. Observation of antimagnetic rotation inCd108

Author

Sukalyan Chattopadhyay, P. V. Madhusudhana Rao, S. Muralithar, T. K. Ghosh, N. Madhavan, P. Datta, Anindya Goswami, R. K. Bhowmik, Ramesh Kumar, H. C. Jain, Sudeb Bhattacharya, R. P. Singh, M. Saha Sarkar, Subrata Pal, and P. K. Joshi

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Total angular momentum quantum number, Routhian, Yrast, Quantum electrodynamics, Angular momentum of light, Collective model, Semiclassical physics, Parity (physics), Atomic physics
Abstract

High spin levels in $^{108}\mathrm{Cd}$ have been populated through $^{100}\mathrm{Mo}(^{13}\mathrm{C},5n\ensuremath{\gamma})^{108}\mathrm{Cd}$ reaction using a 65 MeV $^{13}\mathrm{C}$ beam. The lifetime of the ${14}^{+},{16}^{+},{18}^{+}$, and ${20}^{+}$ levels of the positive parity yrast band of $^{108}\mathrm{Cd}$ have been measured using the Doppler shift attenuation method. The evaluated B(E2) values from the measured lifetimes have been compared with the B(E2) values calculated using the semiclassical model, which assume shears mechanism, and the values obtained from total Routhian surface (TRS) calculations. Both calculations show good agreement with the measured values. In addition, the large ${\mathcal{J}}^{(2)}/B(E2)$ ratio may indicate that a large contribution to the angular momentum of this band is generated by shears mechanism. Thus, the present work indicates that the states of the positive parity yrast band from ${16}^{+}$ onwards in $^{108}\mathrm{Cd}$, originate due to antimagnetic rotation.

Published
2005

19. Quark recombination and elliptic flow

Author

Subrata Pal and Scott Pratt

Subjects
Coalescence (physics), Physics, Quark, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Hadron, Elliptic flow, FOS: Physical sciences, Boltzmann equation, Nuclear Theory (nucl-th), Phase space, High Energy Physics::Experiment, Nuclear Experiment, Anisotropy, Nucleon
Abstract

Elliptic flow systematics for different hadron species have been explained by quark coalescence models. It has been argued that the elliptic asymmetry v_2 should scale with the number of quarks that comprise the hadron. We show how these arguments are sensitive to the relative role of asymmetries in the phase space density vs. asymmetries in the effective volume of emission. We also discuss the degree to which coalescence arguments differ from thermal models. Illustrative calculations based on solving the Boltzmann equation are presented along with the results of blast-wave models. Although the issue is complicated, ambiguities might be clarified by measurements of source-size parameters for nucleons at higher transverse momenta., Comment: 16 pages, 5 figures

Published
2005

20. Photon and neutral pion production inAu+Aucollisions atsNN=130GeV

Author

B. D. Anderson, G. Eppley, Xu Cai, Marcelo Gameiro Munhoz, D. J. Prindle, J. Pluta, Madan M. Aggarwal, Fuqiang Wang, V. V. Belaga, R. E. Tribble, Gerald W Hoffmann, N. Xu, P. Filip, H. Zhang, Vladimir Petrov, E. Yamamoto, T. Dietel, A. K. Dubey, Souvik Das, D. Mishra, R. Witt, M. A. Lisa, A. Stolpovsky, Mirko Planinic, A. Kumar, B. Choi, L. Kotchenda, E. Sugarbaker, A. Lebedev, B. I. Bezverkhny, S. P. Chernenko, W. J. Llope, Sergey Voloshin, Subrata Pal, B. K. Srivastava, P. Seyboth, M. D. Trivedi, K. J. Foley, M. Oldenburg, M. Kaneta, P. Sorensen, F. Du, Peter Graham Jones, V. I. Yurevich, C. O. Blyth, Frank Simon, M. Castro, O. A. Grachov, X. Dong, A. Bravar, A. Rose, Rama Narayana Singaraju, T. W. Henry, G. D. Westfall, J. Gans, Hao-Ze Chen, S. Bhardwaj, Boris Hippolyte, A. H. Tang, Guy Paic, A. Chikanian, S. S. Shimanskii, Michal Sumbera, G. Renault, Alexander Kovalenko, L. V. Nogach, W. Christie, M. Heinz, Lee Stuart Barnby, F. Meissner, Y. Panebratsev, A. I. Kulikov, B. Lasiuk, J. C. Dunlop, D. Grosnick, C-Q. Li, Malgorzata Anna Janik, G. Rai, I. Sakrejda, J. Baudot, M. Calderon De La Barca Sanchez, C. Suire, A. Billmeier, J. G. Cramer, B. Erazmus, V. Faine, W. M. Zhang, Andrey Vasiliev, Zubayer Ahammed, Y. V. Zanevski, Sukalyan Chattopadhyay, B. Norman, M. Shao, H. Long, V. Grigoriev, J. Castillo, M. J. LeVine, R. P. Scharenberg, L. C. Bland, S. W. Wissink, L. Didenko, S. M. Guertin, M. Botje, A. A.P. Suaide, H. S. Matis, Janet Elizabeth Seger, J. Adams, R. L. Ray, E. Potrebenikova, S. K. Badyal, A. Boucham, D. Arkhipkin, D. P. Mahapatra, D. Cebra, Yu Chen, S. Trentalange, Matthew J. Anderson, W. W. Jacobs, D. Reichhold, A. I. Pavlinov, M. Estienne, W. A. Love, L. S. Schroeder, Zhenyu Zhang, F. Liu, M. B. Tonjes, V. Morozov, F. Retiere, Yu Melnick, M. M. de Moura, J. Lauret, S. Bekele, M. L. Miller, T. Ljubicic, V. A. Nikitin, S. V. Razin, M. S. Ganti, A. A. Kuznetsov, V. M. Leontiev, Olivier Ravel, S. Mahajan, A. Ridiger, Thorsten Sven Kollegger, J. Engelage, N. G. Minaev, H. Y. Zhang, Q. Li, D. Magestro, H. Caines, Sudhir Raniwala, L. Molnar, L. Gaudichet, J. Kiryluk, M. Kramer, K. E. Shestermanov, S. Stanislaus, T. D. Gutierrez, D. Hardtke, A. Tai, R. D. Majka, G. Sood, Z. M. Wang, John N. Wood, S. Heppelmann, T. S. McShane, Vitaly Okorokov, G. Rakness, C. Roy, Jay Roberts, H. Ward, H. Bichsel, G. Odyniec, S. Margetis, J. Schambach, Zhongyukun Xu, H. M. Spinka, P. Bhaskar, D. Flierl, Premomoy Ghosh, J. Amonett, L. Martin, J. Klay, Lianshou Liu, G. Skoro, C. Mironov, M. Germain, C. L. Kunz, C. P. Lansdell, C. A. Whitten, J. M. Landgraf, Z. Liu, B. V.K.S. Potukuchi, M. J. Mora-Corral, M. Potekhin, Y. Fisyak, V. Emelianov, Ian Johnson, Yu-Gang Ma, P. Szarwas, C. F. Moore, J. Balewski, Rashmi Raniwala, A. Klyachko, A. K. Bhati, R.J.M. Snellings, D. Keane, M. Strikhanov, S. Gronstal, J. H. Thomas, S. Lange, E. G. Judd, D. D. Koetke, J. E. Draper, S. C. Phatak, Claude Andre Pruneau, Nikolai Smirnov, David Lynn, Vladimir Tikhomirov, C. A. Gagliardi, S. J. Lindenbaum, H. G. Ritter, P.A. Zolnierczuk, R. Stock, J. Mitchell, T. Herston, H. Z. Huang, R. Lednický, P. Chaloupka, L. G. Efimov, J. E. Gonzalez, R. Bellwied, Bedangadas Mohanty, Christina Markert, J. Sandweiss, A. S. Konstantinov, T. Ullrich, J. P. Coffin, O. V. Rogachevski, R. Zoulkarneev, T. K. Nayak, V. Perevoztchikov, V. Trofimov, C. Struck, G. S. Averichev, Julien Faivre, K. Filimonov, B. E. Bonner, A. Ishihara, M. Lopez-Noriega, S. Kabana, Y. P. Viyogi, J. Takahashi, J. Putschke, T. J. Humanic, O. D. Tsai, J. G. Ma, S. U. Pandey, A. E. Yakutin, A. V. Brandin, J. W. Harris, Basanta Kumar Nandi, I.A. Savin, N. T. Porile, Sergey Panitkin, J. W. Watson, J. Marx, M. Guedon, A. M. VanderMolen, E. Gushin, G. J. Kunde, P. Yepes, V. Eckardt, S. E. Vigdor, M. A. Vasiliev, Yu A. Matulenko, M. Horsley, Christian Claude Kuhn, A. Ogawa, B. Stringfellow, Shengli Huang, Thomas A. Trainor, B. Surrow, Sevil Salur, A. S. Hirsch, P. Kravtsov, C. Adler, Jeffrey G. Reid, J. Sowinski, N.D. Gagunashvili, D. Thein, R. Wells, G. Van Buren, M. Kopytine, J. Fu, M. Tokarev, T. W. Ludlam, H. H. Wieman, L. K. Mangotra, R. Manweiler, M. R. Dutta Majumdar, J. M. Nelson, A. M. Poskanzer, N. Schmitz, E. Shahaliev, W. Peryt, V. Ghazikhanian, J. L. Romero, D. Seliverstov, E. Finch, I. Zborovský, X. L. Wang, P. Fachini, Peter Martin Jacobs, E. Hjort, J. Carroll, Gang Wang, S. K. Nayak, M. A. C. Lamont, S. B. Nurushev, Z. Milosevich, Z. Xu, A. P. Meschanin, Anik Gupta, R. V. Cadman, Jianhong Wu, Manish Sharma, Morton Kaplan, Frank Jm Geurts, R. S. Longacre, Debasish Das, Raghunath Sahoo, G. Igo, J. Zoulkarneeva, W. T. Waggoner, K. Schweda, Adam Ryszard Kisiel, H. J. Crawford, R. Fatemi, K. Krueger, A. N. Zubarev, R. Picha, M. Messer, M. Cherney, Thomas Michael Cormier, P. Nevski, F. Laue, A. Szanto de Toledo, T. Pawlak, Jinghui Yang, J. Porter, R.Kh. Kutuev, S. R. Klein, J. Berger, O. Barannikova, D. L. Olson, A. A. Derevschikov, V. B. Dunin, R. Willson, D. G. Underwood, Lijuan Ruan, Q. J. Liu, T. J. Hallman, and T. J. M. Symons

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, 010308 nuclear & particles physics, 01 natural sciences, Particle identification, Spectral line, Nuclear physics, Particle decay, Positron, Pion, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics
Abstract

We report inclusive photon measurements about midrapidity (\y\ gammagamma decay channel. The fractional contribution of the pi(0)-->gammagamma decay to the inclusive photon spectrum decreases by 20%+/-5% between p(t)=1.65 GeV/c and p(t)=2.4 GeV/c in the most central events, indicating that relative to pi(0)-->gammagamma decay the contribution of other photon sources is substantially increasing.

Published
2004

21. Anomalous increase in width of fission-fragment mass distribution as a probe for onset of quasifission reactions in deformed target-projectile system at near and sub-barrier energies

Author

Tinku Sarkar Sinha, T. K. Ghosh, K. S. Golda, Purba Bhattacharya, Dwaipayan Biswas, Sukalyan Chattopadhyay, and Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Mass distribution, Fission, Projectile, Anomalous behavior, Center of mass, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

Fission-fragment mass distribution has been studied for the $^{16}\mathrm{O}+^{232}\mathrm{Th},^{209}\mathrm{Bi}$ systems over an energy range of $102.8--78.6\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ and $81.6--72.6\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$, respectively, in a laboratory frame. The variance of the mass distribution $({\ensuremath{\sigma}}_{m}^{2})$ for the $^{16}\mathrm{O}+^{209}\mathrm{Bi}$ system varies linearly with center of mass energy, while a significant anomalous behavior is found for the system $^{16}\mathrm{O}+^{232}\mathrm{Th}$. Coupled with our earlier observation for the system $^{19}\mathrm{F}+^{232}\mathrm{Th}$ [T. K. Ghosh et al., Phys. Rev. C 69, 031603(R) (2004)], we propose that the accurate measurement of mass distribution is a powerful tool to look for the onset of a nonstatistical reaction mechanism in heavy-ion-induced fission of deformed heavy nuclei.

Published
2004

22. Anomalous increase in width of fission fragment mass distribution inF19+Th232

Author

Purba Bhattacharya, Tinku Sarkar Sinha, Subrata Pal, K. S. Golda, A. Saxena, P. K. Sahu, T. K. Ghosh, S. K. Datta, Sukalyan Chattopadhyay, and Nayana Majumdar

Subjects
Orientation (vector space), Physics, Nuclear and High Energy Physics, Range (particle radiation), Mass distribution, Fission, Coulomb barrier, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

Fission fragment mass distribution has been studied for the system $^{19}\mathrm{F}+^{232}\mathrm{Th}$ over an energy range of $105.4\phantom{\rule{0.3em}{0ex}}\text{MeV}$ to $84.2\phantom{\rule{0.3em}{0ex}}\text{MeV}$ in laboratory frame. For energies, above the Coulomb barrier, the variance of the mass distributions ${\ensuremath{\sigma}}_{m}^{2}$ varies linearly with temperature of the fused system, signifying statistical fusion-fission reaction. However, as energy decreases through the Coulomb barrier, a rapid increase in ${\ensuremath{\sigma}}_{m}^{2}$ is observed for the first time which may be a signal of onset of orientation dependent quasifission reaction.

Published
2004

23. Net charge fluctuations inAu+Aucollisions atsNN=130GeV

Author

A. Stolpovsky, L. Kotchenda, P. Bhaskar, M. Castro, C. A. Whitten, R. S. Longacre, M. J. Mora-Corral, S. Lange, Anik Gupta, J. H. Thomas, Y. Panebratsev, S. M. Guertin, Jianhong Wu, Frank Jm Geurts, S. J. Lindenbaum, Debasish Das, Raghunath Sahoo, D. P. Mahapatra, D. Grosnick, G. Rai, G. Renault, R. Lednický, Yu Chen, N. Xu, P. Filip, G. Igo, J. Zoulkarneeva, M. Heinz, Lee Stuart Barnby, G. D. Westfall, Malgorzata Anna Janik, W. T. Waggoner, F. Retiere, V. V. Belaga, S. B. Nurushev, G. S. Averichev, N. G. Minaev, H. Bichsel, G. Odyniec, G. Rakness, A. Lebedev, D. Thein, A. H. Tang, P. Sorensen, C. Mironov, Y. Fisyak, Zhongyukun Xu, M. Potekhin, A. Ridiger, L. C. Bland, Peter Graham Jones, Guy Paic, A. Chikanian, S. S. Shimanskii, B. E. Bonner, Ian Johnson, J. Balewski, Rashmi Raniwala, Lianshou Liu, W. A. Love, O. D. Tsai, I. Sakrejda, M. Kopytine, J. Fu, J. Marx, E. G. Judd, L. Didenko, S. Heppelmann, H. M. Spinka, David Lynn, D. Flierl, Claude Andre Pruneau, M. Tokarev, Adam Ryszard Kisiel, M. Botje, T. Ullrich, M. L. Miller, A. A.P. Suaide, Vitaly Okorokov, Hao-Ze Chen, H. J. Crawford, M. A. Vasiliev, L. Martin, C. Struck, P. Szarwas, R. Zoulkarneev, A. Boucham, D. Reichhold, B. D. Anderson, Michal Sumbera, A. I. Pavlinov, Julien Faivre, Sevil Salur, A. A. Kuznetsov, A. S. Hirsch, H. H. Wieman, A. Tai, P. Kravtsov, F. Liu, M. B. Tonjes, D. Arkhipkin, A. V. Brandin, S. Kabana, C. Suire, G. Sood, R. Fatemi, J. Takahashi, J. Putschke, J. W. Watson, C. A. Gagliardi, V. Morozov, V. Faine, J. Amonett, C. Adler, T. Herston, D. D. Koetke, J. E. Draper, J. Klay, L. K. Mangotra, J. G. Ma, V. M. Leontiev, Olivier Ravel, P. Seyboth, S. E. Vigdor, Christian Claude Kuhn, A. P. Meschanin, J. Castillo, K. Krueger, M. Calderon De La Barca Sanchez, S. W. Wissink, S. Bekele, R. Manweiler, V. Trofimov, Matthew J. Anderson, D. Hardtke, V. Emelianov, A. K. Bhati, Sergey Voloshin, R. D. Majka, Jeffrey G. Reid, A. Ogawa, D. Keane, S. Gronstal, Shengli Huang, B. Surrow, H. Y. Zhang, Nikolai Smirnov, R. Stock, B. I. Bezverkhny, J. Mitchell, J. Sowinski, R. Picha, Z. M. Wang, S. Margetis, J. Schambach, A. M. Poskanzer, J. P. Coffin, O. V. Rogachevski, B. Erazmus, L. G. Efimov, M. M. Moura, O. A. Grachov, X. Dong, R. V. Cadman, K. Filimonov, C-Q. Li, A. Bravar, W. Christie, R. P. Scharenberg, A. Ishihara, H. S. Matis, T. K. Nayak, K. J. Foley, J. E. Gonzalez, A. I. Kulikov, Bedangadas Mohanty, D. Cebra, Vladimir Petrov, S. P. Chernenko, E. Yamamoto, S. Trentalange, Manish Sharma, S. V. Razin, W. M. Zhang, Andrey Vasiliev, L. Gaudichet, E. Sugarbaker, Jinghui Yang, W. W. Jacobs, J. Lauret, M. Cherney, M. Shao, Thomas Michael Cormier, W. J. Llope, A. Cardenas, Yu Melnick, M. D. Trivedi, Madan M. Aggarwal, J. Kiryluk, Fuqiang Wang, S. Mahajan, Q. Li, D. Mishra, M. Oldenburg, L. Molnar, S. R. Klein, Janet Elizabeth Seger, O. Barannikova, D. L. Olson, A. Rose, Rama Narayana Singaraju, Marcelo Gameiro Munhoz, D. J. Prindle, B. Lasiuk, P. Nevski, M. Lopez-Noriega, N.D. Gagunashvili, G. Eppley, Jay Roberts, H. G. Ritter, H. Z. Huang, Basanta Kumar Nandi, H. Ward, M. Kaneta, F. Meissner, Xu Cai, J. Pluta, T. Dietel, Mirko Planinic, J. Baudot, V. I. Yurevich, R. Bellwied, A. S. Konstantinov, Frank Simon, H. Zhang, H. Long, A. A. Derevschikov, Sukalyan Chattopadhyay, M. S. Ganti, T. Kolleger, M. A. Lisa, V. Grigoriev, S. Stanislaus, C. L. Kunz, T. W. Henry, E. Potrebenikova, Y. V. Zanevski, V. A. Nikitin, M. Guedon, A. M. VanderMolen, R. E. Tribble, J. Adams, K. E. Shestermanov, C. F. Moore, A. N. Zubarev, C. Roy, Gerald W Hoffmann, V. Perevoztchikov, M. Messer, T. Ljubicic, H. Caines, Sudhir Raniwala, M. Germain, V. L. Rykov, B. V.K.S. Potukuchi, A. Klyachko, Sergey Panitkin, Yu-Gang Ma, A. K. Dubey, Vladimir Tikhomirov, P. Chaloupka, Souvik Das, D. Magestro, R. Witt, G. Skoro, J. W. Harris, Subrata Pal, B. K. Srivastava, E. Gushin, G. J. Kunde, C. O. Blyth, P. Yepes, V. Eckardt, J. Gans, S. Bhardwaj, Boris Hippolyte, B. Norman, S. U. Pandey, A. E. Yakutin, J. Engelage, J. C. Dunlop, John N. Wood, Zubayer Ahammed, M. J. LeVine, Premomoy Ghosh, J. M. Landgraf, Z. Liu, T. D. Gutierrez, S. K. Badyal, M. Strikhanov, L. S. Schroeder, P.A. Zolnierczuk, Christina Markert, J. Sandweiss, T. S. McShane, Y. P. Viyogi, K. Schweda, R. Wells, T. J. Humanic, R.Kh. Kutuev, J. Berger, M. R. Dutta Majumdar, I.A. Savin, N. T. Porile, N. Schmitz, E. Shahaliev, I. Zborovský, F. Laue, A. Szanto de Toledo, X. L. Wang, E. Hjort, T. Pawlak, J. Porter, J. Carroll, S. K. Nayak, Yu A. Matulenko, M. Horsley, V. Ghazikhanian, B. Stringfellow, Zhongbin Xu, J. L. Romero, V. B. Dunin, G. Van Buren, A. Kumar, E. Finch, B. Choi, R. Willson, D. G. Underwood, Lijuan Ruan, A. Billmeier, F. Du, T. W. Ludlam, Q. J. Liu, Alexander Kovalenko, J. G. Cramer, J. M. Nelson, T. J. Hallman, T. J. M. Symons, L. V. Nogach, W. Peryt, D. Seliverstov, P. Fachini, Peter Martin Jacobs, Gang Wang, M. A. C. Lamont, Z. Milosevich, Zhenyu Zhang, M. Kramer, C. P. Lansdell, R.J.M. Snellings, S. C. Phatak, and Morton Kaplan

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Jet (particle physics), 01 natural sciences, 7. Clean energy, Resonance (particle physics), Charged particle, Hadronization, Nuclear physics, Pion, Pseudorapidity, 0103 physical sciences, Atomic physics, 010306 general physics, STAR detector
Abstract

We present the results of charged particle fluctuations measurements in Au+Au collisions at rootS(NN)=130 GeV using the STAR detector. Dynamical fluctuations measurements are presented for inclusive charged particle multiplicities as well as for identified charged pions, kaons, and protons. The net charge dynamical fluctuations are found to be large and negative providing clear evidence that positive and negative charged p article production is correlated within the pseudorapidity range investigated. Correlations are smaller than expected based on model-dependent predictions for a resonance gas or a quark-gluon gas which undergoes fast hadronization and freeze-out. Qualitative agreement is found with comparable scaled p+p measurements and a heavy ion jet interaction generation model calculation based on independent particle collisions, although a small deviation from the 1/N scaling dependence expected from this model is observed.

Published
2003

24. Strangeness equilibration in heavy ion collisions

Author

Che Ming Ko, Subrata Pal, and Zi-Wei Lin

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Abundance (chemistry), Monte Carlo method, FOS: Physical sciences, High density, Elementary particle, Strangeness, Kinetic energy, 7. Clean energy, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Astrophysics::Galaxy Astrophysics, Physics, Particle properties, Annihilation, 010308 nuclear & particles physics, Strangeness production, Nuclear matter, Heavy ion, Chemical equilibrium
Abstract

Using a relativistic transport model for heavy ion collisions at energies that are below the threshold for kaon and antikaon production in nucleon-nucleon collisions, we study how their abundances approach the canonical equilibrium during the collisions. We find that kaons are far from chemical equilibrium at the initial and high density stage, and they approach equilibrium only during the expansion stage of the collisions when their production rate is small and becomes comparable to their annihilation rate. In contrast, antikaons approach chemical equilibrium much earlier but eventually fall out of equilibrium again as a result of their large annihilation cross sections in nuclear matter., 4 pages, Revtex, 3 figs incl

Published
2001

25. Charged particle rapidity distributions at relativistic energies

Author

Bin Zhang, Zi-Wei Lin, Bao-An Li, Che Ming Ko, and Subrata Pal

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Critical phenomena, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Observable, 01 natural sciences, Charged particle, Nuclear physics, Pion, Antiproton, 0103 physical sciences, High Energy Physics::Experiment, Rapidity, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics
Abstract

Using a multiphase transport model (AMPT), which includes both initial partonic and final hadronic interactions, we study the rapidity distributions of charged particles such as protons, antiprotons, pions, and kaons in heavy ion collisions at RHIC. The theoretical results for the total charged particle multiplicity at midrapidity are consistent with those measured by the PHOBOS Collaboration in central Au+Au collisions at $\sqrt{s}=56$ and $130A \mathrm{GeV}.$ We find that these hadronic observables are much more sensitive to the hadronic interactions than to the partonic interactions.

Published
2001

26. Antiflow of kaons in relativistic heavy ion collisions

Author

Che Ming Ko, Subrata Pal, Bin Zhang, and Zi-Wei Lin

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Meson, Proton, 010308 nuclear & particles physics, Elliptic flow, FOS: Physical sciences, Impulse (physics), Flow pattern, Nuclear matter, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, 0103 physical sciences, Transverse momentum, High Energy Physics::Experiment, Heavy ion, Nuclear Experiment, 010306 general physics
Abstract

We compare relativistic transport model calculations to recent data on the sideward flow of neutral strange K^0_s mesons for Au+Au collisions at 6 AGeV. A soft nuclear equation of state is found to describe very well the positive proton flow data measured in the same experiment. In the absence of kaon potential, the K^0 flow pattern is similar to that of protons. The kaon flow becomes negative if a repulsive kaon potential determined from the impulse approximation is introduced. However, this potential underestimates the data which exhibits larger antiflow. An excellent agreement with the data is obtained when a relativistic scalar-vector kaon potential, that has stronger density dependence, is used. We further find that the transverse momentum dependence of directed and elliptic flow is quite sensitive to the kaon potential in dense matter., 5 pages, Revtex, 4 figures

Published
2000

27. Hot hypernuclear matter in the modified quark-meson coupling model

Author

Walter Greiner, I. Zakout, Subrata Pal, H. Stöcker, and H.R. Jaqaman

Subjects
Quark, Physics, Coupling constant, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Meson, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Quark model, Scalar (mathematics), FOS: Physical sciences, Nuclear matter, Symmetry (physics), Nuclear Theory (nucl-th), Baryon, Nuclear physics, ddc:530, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Hot hypernuclear matter is investigated in an explicit SU(3) quark model based on a mean field description of nonoverlapping baryon bags bound by the self-consistent exchange of scalar $\sigma, \zeta$ and vector $\omega, \phi$ mesons. The $\sigma, \omega$ mean fields are assumed to couple to the u,d-quarks while the $\zeta, \phi$ mean fields are coupled to the s-quark. The coupling constants of the mean fields with the quarks are assumed to satisfy SU(6) symmetry. The calculations take into account the medium dependence of the bag parameter on the scalar fields $\sigma, \zeta$. We consider only the octet baryons $N,\Lambda,\Sigma,\Xi$ in hypernuclear matter. An ideal gas of the strange mesons $K$ and $K^{*}$ is introduced to keep zero net strangeness density. Our results for symmetric hypernuclear matter show that a phase transition takes place at a critical temperature around 180 MeV in which the scalar mean fields $\sigma, \zeta$ take nonzero values at zero baryon density. Furthermore, the bag contants of the baryons decrease significantly at and above this critical temperature indicating the onset of quark deconfinement. The present results imply that the onset of quark deconfinement in SU(3) hypernuclear matter is much stronger than in SU(2) nuclear matter., Comment: LaTeX/TeX 11 pages (dfg3r.tex), 9 figures in eps format

Published
2000

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