GENXICC2.0: An upgraded version of the generator for hadronic production of double heavy baryons Xicc, Xibc and Xibb

An upgraded (second) version of the package GENXICC (A Generator for Hadronic Production of the Double Heavy Baryons Xi(cc), Xi(bc) and Xi(bb) by CH Chang, J X Wang and X G Wu [its first version in Comput Phys Comm 177 (2007) 467)] is presented Users. with this version being implemented in PYTHIA and a GNU C compiler. may simulate full events of these processes in various experimental environments conveniently In comparison with the previous version, in order to implement it in PYTHIA properly, a subprogram for the fragmentation of the produced double heavy diquark to the relevant baryon is supplied and the interface of the generator to PYTHIA is changed accordingly In the subprogram, with explanation. certain necessary assumptions (approximations) are made in order to conserve the momenta and the QCD 'color' flow for the fragmentation Program summary Program tale GENXICC2 0 Catalogue identifier ADZJ_v2_0 Program summary URL hap //cpc cs club ac uk/summaries/ADZ.I_v2_0 html Program obtainable from CPC Program Library. Queen's University, Belfast, N Ireland Licensing provisions Standard CPC licence, http //cpc cs qub ac ilk/licence/licence html No of lines in distributed program, including test data, etc 102 482 No of bytes in distributed program, including test data, etc 1 469 519 Distribution format tar gz Programming language Fortran 77/90 Computer Any LINUX based on PC with FORTRAN 77 or FORTRAN 90 and GNU C compiler as well Operating system Linux RAM About 20 MByte Classification 11 2 Catalogue identifier of previous version ADZi_vl_0 Journal reference of previous version Comput Phys Comm 177 (2007) 467 Does the new version supersede the previous version? No Nature of problem Hadromc production of double heavy baryons Xi(cc), Xi(bc) and Xi(bb) Solution method The code is based on NRQCD framework With proper options, it can generate weighted and tin-weighted events of hadronic double heavy baryon production When the hadronizations of the produced Jets and double heavy diquark are taken into account in the production, the upgraded version with proper interface to PYTHIA can generate full events Reasons for new version Responding to the feedback from users, we improve the generator mainly by carefully completing the 'final non-perturbative process'. I e the formulation of the double heavy baryon from relevant intermediate diquark In the present version, the information for fragmentation about momentum-flow and the color-flow, that is necessary for PYTHIA to generate full events, is retained although reasonable approximations are made In comparison with the original version, the upgraded one can implement it in PYTHIA properly to do the full event simulation of the double heavy baryon production Summary of revisions 1 We try to explain the treatment of the momentum distribution of the process more clearly than the original version. and show how the final baryon is generated through the typical intermediate diquark precisely 2 We present color flow of the involved processes precisely and the corresponding changes for the program are made 3 The corresponding changes of the program are explained in the paper Restrictions. The color flow, particularly, in the piece of code programming of the fragmentation from the produced colorful double heavy diquark into a relevant double heavy baryon, is treated carefully so as to implement it in PYTHIA properly. Running tune It depends on which option is chosen to configure PYTHIA when generating full events and also on which mechanism is chosen to generate the events Typically, for the most complicated case with gluon-gluon fusion mechanism to generate the mixed events via the intermediate diquark in (cc|(3)S(1)|(3) and (cc)|(1)S(0)|(6) states, under the option, IDWTUP = 1, to generate 1000 events, takes about 20 hours on a 1 8 GHx Intel P4-processor machine, whereas under the option. IDWTUP = 3, even to generate 106 events takes about 40 minutes on the same machine (C) 2010 Elsevier BV All rights reserved.