charybdis2 is hosted by Hepforge, IPPP Durham


Welcome to the CHARYBDIS2 project page


CHARYBDIS2 is the new version of the black hole event generator created in:

C.M. Harris, P. Richardson and B.R. Webber, CHARYBDIS: A Black Hole Event Generator, JHEP 0308:033, hep-ph/0307305, 2003.

This code simulates the production and decay of semi-classical microscopic black holes in proton-proton collisions in models with flat extra dimensions and TeV-scale gravity. The black holes are assumed to be produced well above the fundamental planck scale of the model so that the production is classically dominated. (i.e. the cross section is given by geometrical considerations). The decay is assumed to be dominated by Hawking radiation. For more details on the physical assumptions please refer to the papers in the References section and for details on the implementation please consult the Manual.

For step by step instructions on how to download and set up the latest  release interfaced to HERWIG and other implementations click here.

Latest release

Version 1.0.4

This release includes some minor bug fixes:
  • A minor bug was fixed in various *.f files due to a deprecated form of escaped single quote \' which does not seem to be supported anymore in gfortran and was giving compilation errors.
  • Tested compilation and run with gfortran.
  • A minor bug was fixed in the RMSTAB model for stable remnants. Previous versions only worked with NBODY set to 0. Now NBODY is ignored in this case.

Version 1.0.3

This release includes some bug fixes and minor upgrades:
  • A minor bug was fixed in the les houches files to print the LHAPDF set numbers in the variables PDFSUP and sets the PDFGUP() to zero (LHAPDF implementation only).
  • The precision of the cross-section printed out in the lesh houches files was increased.
  • A new logical switch was introduced (USEMINBHMSS) which when .TRUE. makes the code generate events such that the MINMSS is used for the minimum black hole mass of the events produced, instead of being the partonic centre of mass energy. This is relevant when MJLOST=.TRUE. because if the partonic centre of mass energy is taken as MINMSS then there will be black holes generated with lower masses accompanied by gravitational radiation.
  • A new set of logical switches to allow for several combinations of conservation of leptonic numbers was introduced NLEPTONCSV(0:3). The first one NLEPTONCSV(0) allows for conservation of the total lepton number when .TRUE.. The other three are the corresponding switches for each family of leptons (electron, tau and muon).
  • A new logical switch BHLHOUCES was introduced which when .FALSE. does not include the black hole (which is a documentation particle) in the les houches event file.

Version 1.0.2

This release includes some bug fixes and minor upgrades:
  • A new option to use a charybdis2.init file to input the parameters for the run was added. Also the les houches event .xml files and histories files now contain the full input information in the header which can be placed in a charybdis2.init file to reproduce the run (see detailed description in the charybdis2.init example file provided with the distribution) ;
  • For the standalone implementation, a bug was fixed which was generating weigthted events and setting the weights to 1 in the les houches file inconsistently. The fixed version now simply generates unweighted events just as the other two HERWIG and PYTHIA implementations were already doing. IMPORTANT: previous versions of the standalone CHARYBDIS implementation will provide inconsistent les houches files so this upgrade is compulsory!
  • The n=1 extra dimensions case was added to the data files and the code was adapted accordingly.

Version 1.0.1

In this release several improvements in the model with respect to previous versions of CHARYBDIS1 were introduced.The most important ones are (refer to the manual for further details) :

Previous versions

For CHARYBDIS1 please see this webpage.