CalcHEP 3.4 for collider physics within and beyond the Standard Model

Abstract

We present version 3.4 of the CalcHEP software package which is designed for effective evaluation and simulation of high energy physics collider processes at parton level.The main features of CalcHEP are the computation of Feynman diagrams, integration over multi-particle phase space and event simulation at parton level. The principle attractive key-points along these lines are that it has: (a) an easy startup and usage even for those who are not familiar with CalcHEP and programming; (b) a friendly and convenient graphical user interface (GUI); (c) the option for the user to easily modify a model or introduce a new model by either using the graphical interface or by using an external package with the possibility of cross checking the results in different gauges; (d) a batch interface which allows to perform very complicated and tedious calculations connecting production and decay modes for processes with many particles in the final state.With this features set, CalcHEP can efficiently perform calculations with a high level of automation from a theory in the form of a Lagrangian down to phenomenology in the form of cross sections, parton level event simulation and various kinematical distributions.In this paper we report on the new features of CalcHEP 3.4 which improves the power of our package to be an effective tool for the study of modern collider phenomenology. Program summaryProgram title: CalcHEPCatalogue identifier: AEOV_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOV_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.: 78535No. of bytes in distributed program, including test data, etc.: 818061Distribution format: tar.gzProgramming language: C.Computer: PC, MAC, Unix Workstations.Operating system: Unix.RAM: Depends on process under studyClassification: 4.4, 5.External routines: X11Nature of problem:1.Implement new models of particle interactions.2.Generate Feynman diagrams for a physical process in any implemented theoretical model.3.Integrate phase space for Feynman diagrams to obtain cross sections or particle widths taking into account kinematical cuts.4.Simulate collisions at modern colliders and generate respective unweighted events.5.Mix events for different subprocesses and connect them with the decays of unstable particles.Solution method:1.Symbolic calculations.2.Squared Feynman diagram approach3.Vegas Monte Carlo algorithm.Restrictions:Up to 2→4 production (1→5 decay) processes are realistic on typical computers. Higher multiplicities sometimes possible for specific 2→5 and 2→6 processes.Unusual features:Graphical user interface, symbolic algebra calculation of squared matrix element, parallelization on a pbs cluster.Running time:Depends strongly on the process. For a typical 2→2 process it takes seconds. For 2→3 processes the typical running time is of the order of minutes. For higher multiplicities it could take much longer.