Correlations in high-energy interactions

Abstract

The short-range correlations in rapidity whose existence has been firmly established in high-energy interactions are used to explain chaotic multiplicity behavior in proton-nucleon collisions at 800 GeV. In order to determine the values of higher-order moments from the second-order moment, we have used the pure birth approximation which is in agreement with the "linked pair" approximation of Carruthers.The calculated values of the normalized factorial moments for a given bin size show a good agreement with our data.PACS number(s): 13.85.Hd, 74.40. +kThe recent observation of nonstatistical, multiplicity fluctuations in rapidity has generated considerable interest. In order to explain the behavior of the factorial moments, Carruthers et al. [I-41 have proposed an interesting formalism to explain the observed multiplicity moments in terms of the two particle, short-range correlations. Such correlations lead in a natural way to the observed multiplicity moments, without any further approximations. Following this viewpoint, we explore here the relevance of correlations over a limited range of rapidity bin sizes to the multiplicity fluctuations observed in 800 GeV proton-nucleon interactions. The methodology for this investigation is developed and the results obtained from our data analysis are discussed.The strength of correlation of a specific order is measured by cumulant moments which remove from any multiplicity moment of a given order the contribution from all lower orders of multiparticle correlations. Therefore, in order to evaluate the true higher-order correlations we decompose ordinary factorial moments into factorial cumulant moments [5]. The correlations in rapidity variable y are measured by bin-averaged multiplicity moments. For a given rapidity bin size 6 y = Y / M obtained by dividing the rapidity interval Y into a total of M bins. The normalized factorial cumulant moments are defined as ( 1 ) where are the cumulant correlation functions expressed in terms linear size 6 y . Decomposing the f q into cumulant correof the q-particle density correlation functions f , . Define lation functions by means of a cluster expansion 7, as [equivalent to the inverse of Eq. ( 2 ) ] one relates the bin-(3) averaged normalized factorial moments y m = ( n , ) / 6 y , 1 M ( n , ( n , -l ) . . .which is the mean one-particle rapidity density that is as- ~~( 6~) = -2 ( n , -q + 1 ) )sumed not to vary appreciably within a given bin inter-M m = I (n, )B val, where n , is the hadron multiplicity in a bin m. Each variable of integration yi in Eq. (1) is within the 6 y range ---' i J n d y i f q ( Y l , . . . , Y q ) (4) and the domain of integration am is the hypercube of M ( 6 y ) q m = l n rn i (7, )q

Nuclear effects and intermittency in two dimensions

“…An approach complementary to the one in these experiments has been adopted in [25], to show a linear behaviour in the log-log plot, in the light of the present data. The observed multiplicity moments could also be explained in terms of the two-particle short-range correlations [26] over a wide range of resolution. So far a relation between intermittency and short-range correlations has been established [27], but in a limited range of bin sizes.…”