Fragmentation and multifragmentation of 10.6A GeV gold nuclei

Abstract

: We present the results of a study performed on the interactions of 10.6A GeV gold nuclei in nuclear emulsions. In a minimum bias sample of 1311 interactions, 5260 helium nuclei and 2622 heavy fragments were observed as Au projectile fragments. The experimental data are analyzed with particular emphasis of target separation interactions in emulsions and study of critical exponents. Multiplicity distributions of the fast-moving projectile fragments are investigated. Charged fragment moments, conditional moments as well as two and three -body asymmetries of the fast moving projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and three-body asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents γ, β and τ and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed .

Evidence of phase transition in the break up of Kr-projectile nuclei at 0.95A GeV

“…However, though there is a broad agreement between the values of different exponents as estimated by various groups [34,39], in a number of cases, a careful cross check reveals that the cited values of the exponents suffer from internal inconsistencies and do not follow the corresponding scaling relation [37,38]. There are also reports that the value obtained for an exponent is sensitive to the range of values chosen for the control parameter and to the system under investigation [37,39].…”

“…There are also reports that the value obtained for an exponent is sensitive to the range of values chosen for the control parameter and to the system under investigation [37,39]. It may therefore be inferred that the values of the critical exponents, considered as the representative of critical phenomenon, as cited by various groups are not unambiguous.…”

“…In an attempt to get the signatures of critical behavior in the case of break up of nuclei, several workers have analyzed their experimental data on various systems at different energies [2,[29][30][31][33][34][35][36][37][38][39][40][41]. The experimentally evaluated values of σ , β, τ and γ are then compared with the values obtained for different three-dimensional known systems exhibiting critical behavior.…”

Nuclear fragmentation at 4.5 a GeV/c in 28Si with emulsion interactions

“…In each event, the charge Z ≥ 2 of individual projectile fragments were determined by the combination of several methods, which include grain and delta ray densities. More details on the charge determinations of projectile fragments are given in Reference [8]. Projectile fragments essentially travel with the same speed as that if the parent beam nucleus, so the energy of the produced projectile fragments as high enough to distinguish them easily from the target fragments.…”

Study of the peculiarities of multiparticle production via event-by-event analysis in asymmetric nucleus-nucleus interactions

“…The analysis of the behaviour of the Hurst curve allows to estimate the "force" and "length" of multiparticle correlations in pseudorapidity distributions of secondary particles and to distinguish fluctuations of dynamically correlated distributions of secondary particles from stochastic, connected with statistical reasons [4]. In the present paper we analyzed experimental pseudorapidity distributions of secondary particles obtained in 10.7 A GeV 197 Au interactions with emulsion nuclei [11].…”