GLISSANDO: GLauber Initial-State Simulation AND mOre…

We present a Monte Carlo generator for a variety of Glauber-like models (the wounded-nucleon model, binary collisions model, mixed model, model with hot spots). These models describe the early stages of relativistic heavy-ion collisions, in particular the spatial distribution of the transverse energy deposition which ultimately leads to production of particles from the interaction region. The original geometric distribution of sources in the transverse plane can be superimposed with a statistical distribution simulating the dispersion in the generated transverse energy in each individual collision. The program generates inter alia the fixed-axes (standard) and variable-axes (participant) two-dimensional profiles of the density of sources in the transverse plane and their azimuthal Fourier components. These profiles can be used in further analysis of physical phenomena, such as the jet quenching, event-by-event hydrodynamics, or analysis of the elliptic flow and its fluctuations. Characteristics of the event (multiplicities, eccentricities, Fourier coefficients, etc.) are stored in a ROOT file and can be analyzed off-line. In particular, event-by-event studies can be carried out in a simple way. A number of ROOT scripts is provided for that purpose. Supplied variants of the code can also be used for the proton–nucleus and deuteron–nucleus collisions.Program summaryProgram title: GLISSANDOCatalogue identifier: AEBS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 4452No. of bytes in distributed program, including test data, etc.: 34 766Distribution format: tar.gzProgramming language: C++Computer: any computer with a C++ compiler and the ROOT environment [R. Brun, et al., Root Users Guide 5.16, CERN, 2007, http://root.cern.ch[1]], tested with Intel Core 2 Duo T5200, 1.6 GHz, 1 GB RAMOperating system: Linux Ubuntu 7.04-8.04 (gcc 4.1.3-4.2.3), Scientific Linux CERN 3.08 (gcc 3.2.3), Windows XP with Cygwin (gcc 3.4.4 cygwin special), MacBook Pro OSX 10.5.2 (gcc 4.0.1), ROOT ver. 5.08 5.18RAM: below 120 MBClassification: 17.8External routines: The ROOT system [R. Brun, et al., Root Users Guide 5.16, CERN, 2007, http://root.cern.ch[1]]Nature of problem: Glauber-like models of the initial state in relativistic heavy-ion collisionsSolution method: Glauber Monte Carlo simulation of collision events, analyzed with ROOTRunning time: 40 s/10 000 events for the wounded-nucleon model and 60 s/10 000 events for the mixed model with the Γ distribution, minimum-bias Au + Au collisions with the fixed-last algorithm for nuclear repulsion, dispersion of sources, and hardsphere wounding profile. a typical “physics” run with 500 000 events takes about 1 hour. The use of the Gaussian wounding profile increases the time about 6 times. (All times for Intel Core 2 Duo T5200 1.6 GHz)References:[1] R. Brun, et al., Root Users Guide 5.16, CERN, 2007, http://root.cern.ch