STAR  Computing  Simulation  
Event Generators for STAR


Hijing is a Monte Carlo event generator for parton and particle production in high energy hadronic and nuclear collisions. Based on QCD-inspired models for multiple jet production, it is designed in particular to study jet and mini-jet production and associated particle production in high energy pp, pA and AA collisions. This model incorporates mechanisms such as multiple minijet production, soft excitation, nuclear shadowing of parton distribution functions and jet interactions in dense hadronic matter.


mevsim is a Monte Carlo event generator for general use and very flexible Generates random, uncorrelated multiplicity distributions for any particle type, according to a selected model for pt, y, phi dependence. Total multiplicity for each particle type and model distribution parameters maybe be fixed or allowed to randomly vary from event to event. ven-4.12


Venus is a Monte Carlo event generator for hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. Venus is based on gribov-regge theory and classical relativistic string dynamics. This model also has some very important features. Venus allows secondary interactions to occur, which is very important for hadron-nucleus and nucleus-nucleus scattering. It also incorporates the participation of antiquarks in the colour exchange mechanisms to form strings.

Nexus 1.0

Nexus is a Monte Carlo event generator for lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. Hypothesis is that all high energy interactions are universal. Parton Ladders are building blocks of hadron-hadron scattering. Numerical procedures uses Markov chains on Ladders. Hadronization of parton configurations uses kinky-strings to transform partons to hardrons.


VNI is a general-purpose Monte-Carlo event-generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. On the basis of renormalization-group improved parton description and quantum-kinetic theory, it uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme that is governed by the dynamics itself. The causal evolution from a specific initial state (determined by the colliding beam particles) is followed by the time-development of the phase-space densities of partons, pre-hadronic parton clusters, and final-state hadrons, in position-space, momentum-space and color-space. The parton-evolution is described in terms of a space-time generalization of the familiar momentum-space description of multipl (semi) hard interactions in QCD, involving 2 -> 2 parton collisions, 2 -> 1 parton fusion processes, and 1 -> 2 emission processes. The formation of color-singlet pre-hadronic clusters and their decays into hadrons, on the other hand, is treated by using a spatial criterion motivated by confinement and a non-perturbative model for hadronization.

No afterburning files give the direct output of the parton cascade model where the hadrons are formed from hadronic color singlet clusters which decay into hadrons without any further interactions.

The afterburning files give the combined output of the parton cascade model plus a hadronic cascade which starts from the hadronic color singlet clusters and proceeds through a hadronic cascade.


HIJET generator considers p-A and A-A collisions to be a sum of independent N-N collisions, with cross section and scattering dynamics not dependent on whether the nucleon has previously participated in an interaction. For each primary N-N interaction, a call is made to the MINBIAS routine of the program ISAJET. MINBIAS computes the energy loss of the colliding nucleons and the produced particles. MINBIAS is based on inclusive high energy N-N interactions forming multi-pomeron chains, with each chain fragmenting according to the Field-Feynman algorithm.


RHICEVENT is the HIJET program run for events that have the RHIC energy of 200 GeV per nucleon nucleon center-of-mass energy.

Plasma Bubble

Plasma Bubble is a version of HIJET that generates Van Hove type spherical plasma bubbles. The energy for the bubble is optained from a tagging region defined as a circular cross sectional area within the overlapping nuclei with a radius Rtag. The scheme conserves energy, momentum, charge, baryon, and strangeness. The bubble fragments accord to the plasma model of Koch, Muller and Rafelski.

Landau Plasma Bubbles takes the regular fireballs of Van Hove and replaces then with fireballs which are consistent with thermal fits done on S S collisions at 200 GeV/c per nucleon fixed target.


Smoke Rings are based on a pure geometric idea plus claimed cosmic ray data. Sharp peaks in psuedo-rapidity implies intermittent behavior and particles being emitted at a fixed angle to the beam axis thus forming a ring of particles

Volcano events are special transverse flow events where intial hard parton scatterings have developed into a directed collective flow at some rapidity and phi direction.

DCC(Disoriented Chiral Condensates) are events where pions of low relative momentum (domains) flow together into different rapidity and phi directions.Each domain being a region of false vacuum has isospin breaking leading to a different charge to neutral ratio than the normal vacuum.

Strong CP violating bubbles can be generated with hadronization like Chiral Condensate or Landau bubbles.

For more details please contact Ron Longacre.

April 8, 2000