Multiplicity fluctuations in limited segments of momentum space in statistical models

Abstract

Multiplicity fluctuations in limited segments of momentum space are calculated for a classical pion gas within the statistical model. Results for the grand canonical, canonical, and micro-canonical ensemble are obtained, compared and discussed. We demonstrate that even in the large volume limit correlations between macroscopic subsystems due to energy and momentum conservation persist. Based on the microcanonical formulation we make qualitative predictions for the rapidity and transverse momentum dependence of multiplicity fluctuations. The resulting effects are of similar magnitude as the predicted enhancement due to a phase transition from a quark-gluon plasma to a hadron gas phase, or due to the critical point of strongly interacting matter, and qualitatively agree with recently published preliminary multiplicity fluctuation data of the NA49 SPS experiment.PACS numbers: 24.10.Pa, 24.60. Ky,

Statistical ensembles with finite bath: A description for an event generator

“…We concentrate mainly on particle number distributions and distributions of "conserved" charges and discuss the influence of acceptance cuts in momentum space, conservations laws, and resonance decay on the statistical properties of a sample of hadron resonance gas model events. We extend our previous studies of ideal particle and antiparticle gases [21,22] and of gases of altogether massless particles [23].…”

“…Their y i dependence is, however, rather sensitive to P z conservation. Angular correlations (not studied in this article), however, are strongly sensitive to joint P x and P y conservation [21,22].…”

“…[21][22][23] and [32,33]. Momentum bins are constructed such that each of the five bins constructed contains on average one fifth of the total yield of positively charged particles.…”

“…13 we show the primordial scaled variance ω + of positively charged hadrons in transverse momentum bins Analytical numbers are calculated according to the method developed in Refs. [21,22], using the acceptance bins defined in Table I, and are shown for comparison. The effects of energy-momentum and charge conservation on primordial multiplicity fluctuations and correlations in finite acceptance have been discussed in Refs.…”

“…The effects of energy-momentum and charge conservation on primordial multiplicity fluctuations and correlations in finite acceptance have been discussed in Refs. [21,22]. A few words attempt to summarize.…”