Quantum-Statistical Space-Time Approach to Bose-Einstein Correlations and Multiplicity Distributions

Abstract

A systematic quantum-statistical (density matrix) study of Bose-Einstein correlations (BEC’s) is performed. The minimum number of independent parameters that enter into BEC’s is determined. Expressions for the higher order correlation functions are derived, and the relation between BEC’s and multiplicity distributions is clarified. New results concerning the interplay between the chaotic and the coherent component are presented. The investigation of the isospin dependence of BEC’s leads to the prediction of quantum-statistical π+π− correlations and, related with it, the appearance of squeezed states in particle physics. Soft pions are found to play a specially important part in BEC’s, both with respect to the experimental detection of the new correlation and in the clarification of the role of coherence. A significant increase of the available statistics in BEC’s is necessary in order to test experimentally the new theoretical predictions. Two model sources are investigated: a “static” source and an expanding one. A comparison with a model proposed by Gyulassy, Kauffmann and Wilson is performed.

Multipion Bose-Einstein correlations inpp,p-Pb, and Pb-Pb collisions at energies available at the CERN Large Hadron Collider

“…The building blocks of Bose-Einstein correlations are the pair-exchange magnitudes T ij and the coherent fraction G in the absence of multipion phases [5,18,19,39]. Multipion phases are expected when the spacetime point of maximum pion emission is momentum dependent.…”

“…In the case of no coherent emission, the pair-exchange magnitudes T ij can be extracted according to C QS 2 = 1 + T 2 ij . The extracted pairexchange magnitudes are then used to build the expectation for higher-order QS correlations [5,18,19]. In the absence of coherent emission and multipion phases, the three-and four-pion expected QS correlations are …”

“…The equations which include partial coherence can be found in Refs. [5,18,19]. The T ij factors are tabulated from the first pass over the data and used to build higher-order correlations by means of a weight applied to the fully mixed-event distribution in the second and final pass.…”

“…QS correlations at low relative momentum are known to be sensitive to the spacetime extent (e.g., radius) and dynamics of the particle-emitting source [1][2][3]. Another interesting, although less studied, aspect of QS correlations is the possible suppression due to coherent pion emission [4][5][6][7]. Coherent emission may arise for several reasons such as from the formation of a disoriented chiral condensate (DCC) [8][9][10][11], gluonic or pionic Bose-Einstein condensates (BECs) [12][13][14][15], or multiple coherent sources from pulsed radiation [16].…”

“…Multipion Bose-Einstein correlations could provide an increased sensitivity to coherence as the expected suppression increases with the order of the correlation function [5,18,19].…”