Optical Glauber Modeling in high-energy nuclear collisions

The Optical Glauber Model is used in this study in order to understand the initial conditions in heavy-ion collisions and at the end understand the relationship between the particles produced after the collision. In the first part of this study, the initial geometrical features of the collision as a function of the impact parameter, such as the number of participating nucleons and the number of collisions between nucleons are obtained. Then, after obtaining numerical values for the number of participating nucleons, the study was focused on two distinct particles being produced after the collision and the relationship between them is also determined from the correlation as a function of the impact parameter.peer-reviewe

Measurements of transverse energy distributions in Au+Au collisions at sqrt [sNN ]=200 GeV

Transverse energy ( ET ) distributions have been measured for Au+Au collisions at sqrt[sNN ]=200 GeV by the STAR Collaboration at RHIC. ET is constructed from its hadronic and electromagnetic components, which have been measured separately. ET production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of ET per charged particle agrees well with measurements at lower collision energy, indicating that the growth in ET for larger collision energy results from the growth in particle production. The electromagnetic fraction of the total ET is consistent with a final state dominated by mesons and independent of centrality

Pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at sqrt[sNN ]=200 GeV

The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at sqrt[sNN ]=200 GeV are presented. The charged particle density at midrapidity, its pseudorapidity asymmetry, and centrality dependence are reasonably reproduced by a multiphase transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for pT below 5 GeV/c . The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2< pT <6 GeV/c , with a larger effect at backward rapidity than forward rapidity. Our measurements are in qualitative agreement with gluon saturation and in contrast to calculations based on incoherent multiple partonic scatterings

K*(892)0 production in relativistic heavy ion collisions at sqrt[sNN]=130 GeV

We report the first observation of K*(892)0--> pi K in relativistic heavy ion collisions. The transverse momentum spectrum of (K*0+K*0)/2 from central Au+Au collisions at sqrt[sNN]=130 GeV is presented. The ratios of the K*0 yield derived from these data to the yields of negative hadrons, charged kaons, and phi mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable e+e-, pp, and p-barp results. The data indicate no dramatic reduction of K*0 production in relativistic heavy ion collisions despite expected losses due to rescattering effects.alle Autoren: C. Adler11, Z. Ahammed23, C. Allgower12, J. Amonett14, B. D. Anderson14, M. Anderson5, G. S. Averichev9, J. Balewski12, O. Barannikova9,23, L. S. Barnby14, J. Baudot13, S. Bekele20, V. V. Belaga9, R. Bellwied31, J. Berger11, H. Bichsel30, A. Billmeier31, L. C. Bland2, C. O. Blyth3, B. E. Bonner24, A. Boucham26, A. Brandin18, A. Bravar2, R. V. Cadman1, H. Caines33, M. Calderón de la Barca Sánchez2, A. Cardenas23, J. Carroll15, J. Castillo26, M. Castro31, D. Cebra5, P. Chaloupka20, S. Chattopadhyay31, Y. Chen6, S. P. Chernenko9, M. Cherney8, A. Chikanian33, B. Choi28, W. Christie2, J. P. Coffin13, T. M. Cormier31, J. G. Cramer30, H. J. Crawford4, A. A. Derevschikov22, L. Didenko2, T. Dietel11, J. E. Draper5, V. B. Dunin9, J. C. Dunlop33, V. Eckardt16, L. G. Efimov9, V. Emelianov18, J. Engelage4, G. Eppley24, B. Erazmus26, P. Fachini2, V. Faine2, J. Faivre13, R. Fatemi12, K. Filimonov15, E. Finch33, Y. Fisyak2, D. Flierl11, K. J. Foley2, J. Fu15,32, C. A. Gagliardi27, N. Gagunashvili9, J. Gans33, L. Gaudichet26, M. Germain13, F. Geurts24, V. Ghazikhanian6, O. Grachov31, V. Grigoriev18, M. Guedon13, E. Gushin18, T. J. Hallman2, D. Hardtke15, J. W. Harris33, T. W. Henry27, S. Heppelmann21, T. Herston23, B. Hippolyte13, A. Hirsch23, E. Hjort15, G. W. Hoffmann28, M. Horsley33, H. Z. Huang6, T. J. Humanic20, G. Igo6, A. Ishihara28, Yu. I. Ivanshin10, P. Jacobs15, W. W. Jacobs12, M. Janik29, I. Johnson15, P. G. Jones3, E. G. Judd4, M. Kaneta15, M. Kaplan7, D. Keane14, J. Kiryluk6, A. Kisiel29, J. Klay15, S. R. Klein15, A. Klyachko12, T. Kollegger11, A. S. Konstantinov22, M. Kopytine14, L. Kotchenda18, A. D. Kovalenko9, M. Kramer19, P. Kravtsov18, K. Krueger1, C. Kuhn13, A. I. Kulikov9, G. J. Kunde33, C. L. Kunz7, R. Kh. Kutuev10, A. A. Kuznetsov9, L. Lakehal-Ayat26, M. A. C. Lamont3, J. M. Landgraf2, S. Lange11, C. P. Lansdell28, B. Lasiuk33, F. Laue2, J. Lauret2, A. Lebedev2, R. Lednický9, V. M. Leontiev22, M. J. LeVine2, Q. Li31, S. J. Lindenbaum19, M. A. Lisa20, F. Liu32, L. Liu32, Z. Liu32, Q. J. Liu30, T. Ljubicic2, W. J. Llope24, G. LoCurto16, H. Long6, R. S. Longacre2, M. Lopez-Noriega20, W. A. Love2, T. Ludlam2, D. Lynn2, J. Ma6, R. Majka33, S. Margetis14, C. Markert33, L. Martin26, J. Marx15, H. S. Matis15, Yu. A. Matulenko22, T. S. McShane8, F. Meissner15, Yu. Melnick22, A. Meschanin22, M. Messer2, M. L. Miller33, Z. Milosevich7, N. G. Minaev22, J. Mitchell24, C. F. Moore28, V. Morozov15, M. M. de Moura31, M. G. Munhoz25, J. M. Nelson3, P. Nevski2, V. A. Nikitin10, L. V. Nogach22, B. Norman14, S. B. Nurushev22, G. Odyniec15, A. Ogawa21, V. Okorokov18, M. Oldenburg16, D. Olson15, G. Paic20, S. U. Pandey31, Y. Panebratsev9, S. Y. Panitkin2, A. I. Pavlinov31, T. Pawlak29, V. Perevoztchikov2, W. Peryt29, V. A. Petrov10, M. Planinic12, J. Pluta29, N. Porile23, J. Porter2, A. M. Poskanzer15, E. Potrebenikova9, D. Prindle30, C. Pruneau31, J. Putschke16, G. Rai15, G. Rakness12, O. Ravel26, R. L. Ray28, S. V. Razin9,12, D. Reichhold8, J. G. Reid30, G. Renault26, F. Retiere15, A. Ridiger18, H. G. Ritter15, J. B. Roberts24, O. V. Rogachevski9, J. L. Romero5, A. Rose31, C. Roy26, V. Rykov31, I. Sakrejda15, S. Salur33, J. Sandweiss33, I. Savin10, J. Schambach28, R. P. Scharenberg23, N. Schmitz16, L. S. Schroeder15, A. Schüttauf16, K. Schweda15, J. Seger8, D. Seliverstov18, P. Seyboth16, E. Shahaliev9, K. E. Shestermanov22, S. S. Shimanskii9, G. Skoro9, N. Smirnov33, R. Snellings15, P. Sorensen6, J. Sowinski12, H. M. Spinka1, B. Srivastava23, E. J. Stephenson12, R. Stock11, A. Stolpovsky31, M. Strikhanov18, B. Stringfellow23, C. Struck11, A. A. P. Suaide31, E. Sugarbaker20, C. Suire2, M. Sumbera20, B. Surrow2, T. J. M. Symons15, A. Szanto de Toledo25, P. Szarwas29, A. Tai6, J. Takahashi25, A. H. Tang15, D. Thein6, J. H. Thomas15, M. Thompson3, V. Tikhomirov18, M. Tokarev9, M. B. Tonjes17, T. A. Trainor30, S. Trentalange6, R. E. Tribble27, V. Trofimov18, O. Tsai6, T. Ullrich2, D. G. Underwood1, G. Van Buren2, A. M. VanderMolen17, I. M. Vasilevski10, A. N. Vasiliev22, S. E. Vigdor12, S. A. Voloshin31, F. Wang23, H. Ward28, J. W. Watson14, R. Wells20, G. D. Westfall17, C. Whitten, Jr.6, H. Wieman15, R. Willson20, S. W. Wissink12, R. Witt33, J. Wood6, N. Xu15, Z. Xu2, A. E. Yakutin22, E. Yamamoto15, J. Yang6, P. Yepes24, V. I. Yurevich9, Y. V. Zanevski9, I. Zborovský9, H. Zhang33, W. M. Zhang14, R. Zoulkarneev10, and A. N. Zubarev

Open charm yields in d+Au collisions at sqrt[sNN]=200 GeV

Midrapidity open charm spectra from direct reconstruction of D0(D0-bar)-->K± pi ± in d+Au collisions and indirect electron-positron measurements via charm semileptonic decays in p+p and d+Au collisions at sqrt[sNN]=200 GeV are reported. The D0(D0-bar) spectrum covers a transverse momentum (pT) range of 0.1<pT<3 GeV/c, whereas the electron spectra cover a range of 1<pT<4 GeV/c. The electron spectra show approximate binary collision scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon binary interaction at midrapidity for open charm production from d+Au collisions at BNL RHIC is d sigma NNcc-bar/dy=0.30±0.04(stat)±0.09(syst) mb. The results are compared to theoretical calculations. Implications for charmonium results in A+A collisions are discussed

K(892)* resonance production in Au+Au and p+p collisions at sqrt[sNN]=200GeV

The short-lived K(892)* resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements of K* in sqrt[sNN]=200GeV Au+Au and p+p collisions reconstructed via its hadronic decay channels K(892)*0-->K pi and K(892)*±-->K0S pi ± using the STAR detector at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The K*0 mass has been studied as a function of pT in minimum bias p+p and central Au+Au collisions. The K*pT spectra for minimum bias p+p interactions and for Au+Au collisions in different centralities are presented. The K*/K yield ratios for all centralities in Au+Au collisions are found to be significantly lower than the ratio in minimum bias p+p collisions, indicating the importance of hadronic interactions between chemical and kinetic freeze-outs. A significant nonzero K*0 elliptic flow (v2) is observed in Au+Au collisions and is compared to the K0S and Lambda v2. The nuclear modification factor of K* at intermediate pT is similar to that of K0S but different from Lambda . This establishes a baryon-meson effect over a mass effect in the particle production at intermediate pT (2<pT <= 4GeV/c)