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[Licence| Download | New Version Template] adzj_v2_1.tar.gz(1387 Kbytes)
Manuscript Title: GENXICC2.1: An Improved Version of GENXICC for Hadronic Production of Doubly Heavy Baryons
Authors: Xian-You Wang, Xing-Gang Wu
Program title: GENXICC2.1
Catalogue identifier: ADZJ_v2_1
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 184(2013)1070
Programming language: FORTRAN 77/90.
Computer: Any LINUX based PC with FORTRAN 77 or Fortran 90 and a GNU C compiler.
Operating system: LINUX.
RAM: About 2.0 MB
Supplementary material: Details of the changes implemented are available here.
Keywords: Event generator, Doubly heavy baryons, Hadronic production.
Classification: 11.2.

Does the new version supersede the previous version?: No

Nature of problem:
Hadronic production of doubly heavy baryons Ξcc, Ξbc and Ξbb.

Solution method:
The upgraded version with proper interface to PYTHIA can generate full production and decay events, either weighted or unweighted, conveniently and effectively. Especially, the unweighted events are generated by using an improved hit-and-miss technology.

Reasons for new version:
Responding to the feedback from users of CMS and LHCb groups at the large hadronic collider, and based on the recent improvements of PYTHIA on the color-flow problem, we improve the efficiency for generating the unweighted events, and also improve the color-flow part for further hadronization. In particular, an interface has been added to import the output production events into a suitable form for PYTHIA8.0 simulation, in which the color-flow during the simulation can be correctly set.

Summary of revisions:
The revisions are outlined in a pdf file which may be otained by clicking the "Supplementary material:" link above.

Running time:
It depends on which option is chosen to match PYTHIA when generating the full events and also which mechanism is chosen to generate the events. Typically, for the dominant gluon-gluon fusion mechanism to generate the mixed events via the intermediate diquarks in (cc)[3S11]bar3 and (cc)[1S01]6 states, setting IDWTUP=3 and unwght=.true., it takes 30 minutes to generate 105 unweighted events on a 2.27GHz Intel Xeon E5520 processor machine; setting IDWTUP=3 and unwght=.false. or IDWTUP=1 and IGENERATE=0, it only needs 2 minutes to generate the 105 baryon events (the fastest way, for theoretical purpose only). As a comparison, for previous GENXICC versions, if setting IDWTUP=1 and IGENERATE=1, it takes about 22 hours to generate 1000 unweighted events.