New approach to fragmentation reactions: The nuclear lattice model

An extensive study of GeV light-ion-induced multifragmentation and its possible interpretation in terms of a nuclear liquid-gas phase transition has been performed with the Indiana Silicon Sphere (ISiS) 4π detector array. Measurements were performed with 5-15 GeV/c p, p, and π − beams incident on 197 Au and 2-5 GeV 3 He incident on nat Ag and 197 Au targets. Both the reaction dynamics and the subsequent decay of the heavy residues have been explored. The data provide evidence Preprint submitted to Elsevier Science 10 March 2018for a dramatic change in the reaction observables near an excitation energy of E*/A = 4-5 MeV per residue nucleon. In this region, fragment multiplicities and energy spectra indicate emission from an expanded/dilute source on a very short time scale (20-50 fm/c). These properties, along with caloric curve and scaling-law behavior, yield a pattern that is consistent with a nuclear liquid-gas phase transition.

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“…The bond-breaking probability for the model is determined from the excitation energy via the relation [107] …”

Section: Heat Capacitymentioning

confidence: 99%

Light-ion-induced multifragmentation: The ISiS project

et al. 2006

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“…It turned out to be quite successful [26,27] to explain deuteron data in the Bevalac regime [28]. This idea has already been used, when the primary collision stage is described by cruder models [19] when the state at the end of the collision is supposed to be completely at random [29,30]. Therefore, our approach includes detailed dynamics in the first stage and a simple model for the generation of fragments in the second stage.…”

Section: Introductionmentioning

confidence: 99%

Multifragmentation in the intranuclear cascade ? percolation approach

Volant¹

1989

Z. Physik A - Atomic Nuclei

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“…Indeed, percolation models have long been used in the analysis and interpretation of multifragmentation data [28,[64][65][66][67][68][69]. In bond percolation, each lattice site corresponds to a monomer, and a proportion p of active bonds is set randomly between sites.…”

Section: Experimental Analysis Collisions Ofmentioning

confidence: 99%

Nuclear Multifragmentation Time Scale and Fluctuations of the Largest Fragment Size

et al. 2013

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Distributions of the largest fragment charge, Zmax, in multifragmentation reactions around the Fermi energy can be decomposed into a sum of a Gaussian and a Gumbel distribution, whereas at much higher or lower energies one or the other distribution is asymptotically dominant. We demonstrate the same generic behavior for the largest cluster size in critical aggregation models for small systems, in or out of equilibrium, around the critical point. By analogy with the timedependent irreversible aggregation model, we infer that Zmax distributions are characteristic of the multifragmentation time-scale, which is largely determined by the onset of radial expansion in this energy range. Introduction In central heavy-ion collisions at beam energies of ∼20-150 MeV/A multiple production of nuclear fragments can be observed, compatible with the quasi-simultaneous break-up of finite pieces of excited nuclear matter [1][2][3][4][5][6][7]. This so-called "nuclear multifragmentation" is a fascinating process [8] which has long been associated with a predicted liquid-gas coexistence region in the nuclear matter phase diagram at sub-critical temperatures and sub-saturation densities [9][10][11]. Statistical [12][13][14][15][16][17][18][19] and dynamical [20][21][22][23][24] aspects have been widely studied, and evidences supporting equally well either a continuous phase transition of the liquid-gas universality class [13,14,[25][26][27][28][29][30], a discontinuous ("first-order") transition occurring within the coexistence region [29][30][31][32][33][34][35], or indeed the survival of initial-state correlations in a purely dynamical picture [36,37] have been presented. This state of affairs well demonstrates the difficulty of quantitatively identifying a phase transition in small systems such as atomic nuclei, where finite-size effects blur the nature of the transition [38][39][40] whose order may indeed change with the size of the system [29,30], along with the importance of long-range Coulomb forces [4,19,41,42], and presence of dynamical effects such as radial flow [43][44][45][46][47][48][49].In this context we have tried to establish generic features of multifragmentation in order to deduce its nature in a less model-dependent way. In our previous works [50], we used the model-independent universal fluctua-

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New approach to fragmentation reactions: The nuclear lattice model

Cited by 160 publications

References 18 publications

Light-ion-induced multifragmentation: The ISiS project

Light-ion-induced multifragmentation: The ISiS project

Multifragmentation in the intranuclear cascade ? percolation approach

Nuclear Multifragmentation Time Scale and Fluctuations of the Largest Fragment Size

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