CMBE v05—Implementation of a toy-model for chaos analysis of relativistic nuclear collisions at the present BNL energies

Abstract In this paper we present a new version of Chaos Many-Body Engine (CMBE) Grossu et al. (2014) [1] . Inspired by the Mean Free Path concept, we implemented a new parameter, namely the “Mean Free Time” , which is defined as the mean time between one particle’s creation and its stimulated decay. This new parameter should be understood as an effect of the nuclear environment and, as opposed to the particle lifetime, it has the advantage of not being affected by the relativistic dilation. In [2] we presented a toy-model for chaos analysis of relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration). In this work, we extended our model to 200 A GeV (the maximum BNL energy). New version program summary Program title: Chaos Many-Body Engine v05 Catalogue identifier: AEGH_v5_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEGH_v5_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Microsoft Public License (Ms-PL) No. of lines in distributed program, including test data, etc.: 638984 No. of bytes in distributed program, including test data, etc.: 15918340 Distribution format: tar.gz Programming language: Visual C# .Net 2010 Computer: PC Operating system:  .Net Framework 4.0 running on MS Windows RAM: 128 MB Classification: 24.60.Lz, 05.45.a Catalogue identifier of previous version: AEGH_v4_0 Journal reference of previous version: Computer Physics Communications 185 (2014) 1339 Does the new version supersede the previous version?: Yes Nature of problem: Toy-model for relativistic nuclear collisions at present BNL energies. Solution method: Relativistic many-body OOP engine, including a reactions module. Reasons for new version: 1. Implementation of the “Mean Free Time” parameter; 2. Implementation of a new example of use for relativistic nuclear collisions at present BNL energies. Summary of revisions: 1. Implementation of a new parameter, namely the “Mean Free Time”, defined as the mean time between one particle’s creation and its stimulated decay. The Mean Free Time should be understood as an effect of the nuclear environment and, as opposed to the particle lifetime, it is measured in the observation system (not affected by the relativistic dilation). Following this purpose, a new tag (MeanFreeTime) was added in the “Particles” section of the specific XML reactions input file described in [2] . 2. Analysis ∖Chaos Analysis ∖Double ∖Other: Implementation of a, more reliable, fuzzy algorithm [3] for probability distributions. 3. Math ∖Vector ∖GetRandomVector: Bug correction (the distribution is now isotropic). 4. Simulations ∖Collider: New example of use for relativistic nuclear collisions at present BNL energies [4] . Additional comments: Inspired by existing nuclear billiards [5] , [6] , in [2] we implemented a toy-model for relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration [7] , [8] ). In this work, we extended our model to higher energies. Following this purpose, we inherited the SimulationCollisionExample class (the SimulationColliderExample class), and employed an extended set of reactions (the ColliderReactions.xml file). The, previously discussed, Mean Free Time concept is also playing an important role in this context. As an exemplification of CMBE capabilities, in Fig. 1 , Fig. 2 , Fig. 3 we present some preliminary results [9] for 1000 Au–Au events at 200 A GeV (the maximum BNL energy [4] ), simulated at 0.1 Fm/c temporal resolution. Download high-res image (581KB) Download full-size image Fig. 1 . Au–Au at 200 A GeV: the emerging particles at 200 Fm/c. (Red—P, Dark Red—Anti-P, Gold—N, Dark Orange—Anti-N, Green— π + , Lime Green— π − , Pale Green— π 0 , Steel Blue— K + , Medium Blue— K − , Medium Violet Red— K 0 , Purple—Anti- K 0 .) (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Download high-res image (905KB) Download full-size image Fig. 2 . Au–Au at 200 A GeV: the time variation of the pseudorapidity η of the emerging particles. Download high-res image (130KB) Download full-size image Fig. 3 . Au–Au at 200 A GeV: the total particle multiplicity in relation with the impact parameter b .