Ju n 20 05 Boost Invariance and Multiplicity Dependence of the Charge Balance Function in π + p and K + p Collisions at √ s = 22 GeV / c

(EHS/NA22 Collaboration) 1 Institute of Physics, AM-375036 Yerevan, Armenia 2 Institute of Particle Physics, Hua-Zhong Normal University, Wuhan 430070, China 3 Department of Physics, University of Antwerp, B-2610 Wilrijk, Belgium 4 Centro Brasileiro de Pesquisas Fisicas, BR-22290 Rio de Janeiro, Brazil 5 Radboud University Nijmegen/NIKHEF, NL-6525 ED Nijmegen, The Netherlands 6 Institute for High Energy Physics of Tbilisi State University, GE-380086 Tbilisi, Georgia; now at Northwestern Univ., Evanston, U.S.A. 7 Scobeltsyn Institute of Nuclear Physics, Lomonosow Moscow State University, RU-119899 Moscow, Russia Now at DESY, Hamburg, Germany Boost invariance and multiplicity dependence of the charge balance function are studied in πp and Kp collisions at 250 GeV/c incident beam momentum. Charge balance, as well as charge fluctuations, are found to be boost invariant over the whole rapidity region, but both depend on the size of the rapidity window. It is also found that the balance function becomes narrower with increasing multiplicity, consistent with the narrowing of the balance function when centrality and/or system size increase, as observed in current relativistic heavy ion experiments.