One- and two-dimensional analysis of intermittency in ultrarelativistic nucleus-nucleus interactions

Abstract

Corrected scaled factorial moments are calculated for the multiplicity distributions in one-(pseudorapidity and azimuthal angle) and two-dimensional (the product of pseudorapidity and azimuthal angle) phase spaces. An intermittency power-law growth is observed in the central collisions of S and ' 0 at 2003 GeV, ' 0 at 603 GeV, and He at =1403 GeV, while for Si at 14.5A GeV it is observed for inclusive interactions in nuclear emulsion. The effect is much pronounced for higher dimensions. The data for the ' 0 beam at 2003 GeV satisfy the condition for two phases occurring together.In a series of papers, Bialas and Peschanski [1] have recently developed a method of analyzing the data on high-energy interactions in terms of scaled factorial moments (SFM) as a function of decreasing rapidity intervals to search for nonstatistical fluctuations. They suggested that if intermittency exists, then the normalized factorial moments of the multiplicity distribution should exhibit a characteristic power-law dependence. Such a dependence of the factorial moments has been observed recently in leptonic [2], hadronic [3], and nuclear collisions [4,5]. The observation of intermittency may be due to the self-similar structures in the random cascading for elementary processes or in nuclear collisions by the second-order-phase transition from the quark-gluonplasma to the final hadronic state. What causes intermittency may lead to the fundamental question about the production mechanism of these particles, which is highly desirable. Most of the values of the intermittency exponents, so far, have been found in one-dimensional distributions of pseudorapidity (g) and very scanty data have been available in the azimuthal angle (P) or in the two-dimensional ( ri, P ) distributions. Moreover, at present, the results available from different experiments are difficult to compare, as they depend upon the shape of the single-particle spectra, which are different in each case and also on the choice of variables used. From the experimental point of view, one needs more data on the intermittency exponent in rl, p, and site dimensions in order to have a better understanding of the intermittency.On the theoretical side, one needs a new technique (variable) with which one can compare the available results from the different experiments.Recently, in Ref.[5], we have given the evidence for the intermittent behavior of the q distributions for S and ' 0 at 2003 GeV, and ' O at 60M GeV (expt. No.EMU 08) and for a proton beam at 800 GeV (expt. No. FNAL 751) in emulsion. Our data were not corrected for the shape of the single-particle pseudorapidity distribution. In the present paper, we have applied not only the correction factors to the factorial moments in ri, P, and gP phase spaces, but also have increased the statistics of the data used. We also present, for the first time, the evidence of intermittency in g intervals for Si at 14.5AGeV (BNL expt. No. 847) and for a low-mass ion like He at =1403 GeV.The details for S at 2003 GeV (beam A), ' 0 at 200M GeV...

Intermittency in nuclear multifragmentation at relativistic energy

“…3 [10]. We conclude that the fragment charge distribution of ^^^U into a nonfissile multifragmentation process is fitted with a power law.…”

“…In doing so, one must be careful in selecting the smallest bin, which must not be smaller than the resolution of the detector as discussed in Ref. [10].…”

Genuine two particle correlations of target fragments in nuclear interactions

“…The data for the 28 Si-AgBr interactions were obtained from Illford G5 emulsion stacks exposed to an 28 Si beam of energy 14.5 AGeV from the alternating gradient synchrotron (AGS) at Brookhaven National Laboratory (BNL) [15]. A Leitz Metaloplan microscope with a 10Â objective and 10Â ocular lens fitted with a semi-automatic scanning stage was used to scan the plates.…”

Self-affine fluctuations of pions and protons and nonthermal phase transition in hadron–nucleus interactions

“…In ref. 25, the minimum should be searched for in different M ranges so as to probe different regimes of multihadron production at different scales as indicated by high-order factorial moments, a feature not observed in the full M range λ q studies where saturation is reached at certain q values [16,27,28]. Such minima in limited M ranges were indeed found in hadronic [29] and nuclear [25,30,31] collisions.…”

“…So far, most of the analyses were performed in one-dimension. Only limited attempts have been made to study the nonthermal phase transition in higher dimensions [13,27,31]. Therefore, in this paper, we have carried out a detailed study for the evidence of a nonthermal phase transition in the two-dimensional polar (emission) angle versus azimuthal angle phase space considering the anisotropy of multiparticle production in the π − -AgBr interaction at 350 GeV/c.…”