August 11, 2005 [email protected] - ISMD05 Kromer iz 1 ENERGY AND RAPIDITY DEPENDENCE OF ELECTRIC CHARGE CORRELATIONS AT 20 – 158 GeV BEAM ENERGIES AT THE CERN SPS (NA49) P. Christakoglou, A. Petridis, M. Vassiliou University of Athens, for the NA49 collaboration.
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August 11, [email protected] - ISMD05 Kromeriz1 ENERGY AND RAPIDITY DEPENDENCE OF ELECTRIC CHARGE CORRELATIONS AT 20 – 158 GeV BEAM ENERGIES.
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The Balance function is defined as a correlation in y of oppositely charged particles, minus the correlation of same charged particles, normalized to the total number of particles.
where P1: any rapidity interval in the detector
P2: relative rapidity interval
• Bass-Danielewicz-Pratt, Phys.Rev.Lett.85, 2000• D. Drijard et al, Nucl. Phys. B(155), 1979
The Balance Function is constructed in such way that can identify correlated pairs of oppositely charged particles on a statistical basis.
This term is the conditional probability of detecting a particle of type b in the bin P2 whilst there is a particle of type a in the bin P1.
The numerator counts the pairs that satisfy both criteria within an event and then is summed over all events. The denominator counts particles that were used for the creation of pairs within an event. It is then summed over all events.
Delayed hadronization scenario of an initially deconfined phase.S.A. Bass, P. Danielewicz, S. Pratt, Phys. Rev. Lett. 85, 2689 (2000).
J. Adams et al. (STAR collaboration), Phys. Rev. Lett. 90, 172301 (2003).
C. Alt et al. (NA49 collaboration), Phys. Rev. C 71, 034903 (2005).
Part of the decrease could be attributed to the presence of the resonances’ decay products.
P. Bozek, W. Broniowski, W. Florkowski, nucl-th/0310062.
P. Bozek, W. Broniowski, W. Florkowski, nucl-th/0402028.
Statistical hadronization model with the addition of hydrodynamic expansion. Several smaller fireballs with individual charge conservation + blast wave model.
S. Cheng et al., Phys. Rev. C 69, 054906 (2004).
Quark coalescence model of an initially deconfined phase reproduced the values of the width from STAR.
BF could give us insight about the time of hadronization.
Results @ √sNN =17.2 GeV show that:
The width of the BF takes its maximum value for p+p interactions. The width of the BF for shuffled and HIJING events doesn’t show any sign of system size or centrality dependence. The width decreases with increasing system size and centrality in Pb+Pb interactions. The centrality dependence is of the order of (17 ± 3)%.The effect is not apparent in the forward rapidity region.STAR experiment shows the same trend. The centrality dependence is of the order of (14 ± 2)%.
Preliminary results @ √sNN =8.8 GeV show that:The width of the BF behaves in a similar way as in the previous case for both real and shuffled data. The centrality dependence is of the order of (14.5 ± 5)%.The effect is not apparent in the forward rapidity region.
Preliminary results from the energy scan show that:We have a plateau of the parameter W in the energy range 30-80AGeV.Then this parameter rises towards RHIC (LHC?) energies.
C. Alt, T. Anticic, B. Baatar, D. Barna, J. Bartke, L. Betev, H. Bialkowska, C. Blume, B. Boimska, M. Botje, J. Bracinik, R. Bramm, P. Buncic, V. Cerny, P. Christakoglou, O. Chvala , J.G. Cramer, P. Csató, P. Dinkelaker, V. Eckardt, D. Flierl, Z. Fodor, P. Foka, V. Friese, J. Gál, M. Gazdzicki, V. Genchev , G. Georgopoulos, E. Gladysz, K. Grebieszkow, S. Hegyi, C. Höhne, K. Kadija, A. Karev, M. Kliemant, S. Kniege, V.I. Kolesnikov, E. Kornas, R. Korus, M. Kowalski, I. Kraus, M. Kreps, A. Laszlo, M. van Leeuwen, P. Lévai, L. Litov, B. Lungwitz, M. Makariev, A.I. Malakhov, M. Mateev, G.L. Melkumov, M. Mitrovski, J. Molnár, St. Mrówczynski, V. Nicolic, G. Pálla, A.D. Panagiotou, D. Panayotov, A. Petridis, M. Pikna, D. Prindle, F. Pühlhofer, R. Renfordt, C. Roland, G. Roland, M. Rybczynski, A. Rybicki, A. Sandoval, N. Schmitz, T. Schuster, P. Seyboth, F. Siklér, B. Sitar, E. Skrzypczak, G. Stefanek , R. Stock, C. Strabel, H. Ströbele, T. Susa, I. Szentpétery, J. Sziklai, P. Szymanski, V. Trubnikov, D. Varga, M. Vassiliou, G.I. Veres, G. Vesztergombi, D. Vranic, A. Wetzler, Z. Wlodarczyk, I.K. Yoo, J. Zimányi
NIKHEF, Amsterdam, Netherlands.Department of Physics, University of Athens, Athens, Greece.Comenius University, Bratislava, Slovakia.KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary.MIT, Cambridge, USA.Institute of Nuclear Physics, Cracow, Poland.Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany.Joint Institute for Nuclear Research, Dubna, Russia.Fachbereich Physik der Universität, Frankfurt, Germany.CERN, Geneva, Switzerland.Institute of Physics Swietokrzyska Academy, Kielce, Poland.Fachbereich Physik der Universität, Marburg, Germany.Max-Planck-Institut für Physik, Munich, Germany.Institute of Particle and Nuclear Physics, Charles University, Prague, Czech Republic.Department of Physics, Pusan National University, Pusan, Republic of Korea.Nuclear Physics Laboratory, University of Washington, Seattle, WA, USA.Atomic Physics Department, Sofia University St. Kliment Ohridski, Sofia, Bulgaria.Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria.Institute for Nuclear Studies, Warsaw, Poland.Institute for Experimental Physics, University of Warsaw, Warsaw, Poland.Rudjer Boskovic Institute, Zagreb, Croatia.