====================================================================== page 1 HEPG BANKS IN HERWIG, ISAJET, PYTHIA ------------------------------------- RUNNING CDF2SIM MADE FROM DEVELOPMENT 15-SEP. USE AMENDED mc_event.cc SO HERWIG RUNS OK. HISTOGRAMS ETC MADE IN MY OWN FORTRAN ROUTINE - (CALLED FROM GeneratorModule.cc). ==================================================================== page 2 SOME PROBLEMS AND ODDITIES - FROM RUNNING THE GENERATORS PLUS THE GEANT INTERFACE 1. IF WE USE QQ AND SET TRUE THE OPTIONS: Decay_Bc Decay_Upsilon Decay_B_Baryons Decay_prompt_charm THEN: HERWIG OK ISAJET - LOTS OF COMPLAINTS TRY_Generic_Bank::... PYTHIA - ABORTS ON EVENT 61 - ABORT OCCURS IN mc_event, A QQ INTERFACE PROBLEM. 2. IN ALL GENERATORS, SOME LEPTONS "DECAY". THESE ARE LEPTONS FROM W FROM TOP, "ADJUSTED". THESE ARE A NUISANCE IN ISAJET BECAUSE THE INITIAL LEPTONS HAVE STATUS = 2. 3. FIRST 16 OR SO ENTITIES IN PYTHIA (ALL STATUS = 3) HAVE NO DAUGHTERS. 4. STRINGS IN PYTHIA HAVE TWO MOTHERS. MUST NOTE IF YOU WANT TO KNOW IF A B HADRON COMES FROM SOME b QUARK BY GOING "UPWARDS". 5. IN HERWIG (AND PYTHIA, SEE ABOVE) WE CANNOT EASILY AND RELIABLY FIND PARTON ANCESTORS OF HADRONS. ====================================================================== page 3 PROBLEMS AND ODDITIES CONTD. 6. TOP DECAYS: HERWIG - ALWAYS TOP -> b x y, WITH (x y) = (u dbar) or (c sbar) or two-leptons. ISAJET - TOP -> b W (+ gluons) -> b x y 40% b x y gluons 59% b x y q qbar 0.5% b x y gamma 0.5% PYTHIA - TOP -> b W (+ gluons) -> b x y 97.5% b x y gluons 0.5% b c dbar 2% b s numu 1/2000 (??) 7. B BARYONS: HERWIG - NONE. ISAJET - IN 10% OF EVENTS, MOSTLY M = 5.810, NO LAMBDA_B PYTHIA - IN 20% OF EVENTS, MOSTLY LAMBDA_B (OR DECAY TO IT). 8. PIZERO LIFETIME - ZERO IN ISAJET, NON-ZERO IN HERWIG AND PYTHIA. SO MANY MORE HEPG VERTICES IN HERWIG AND PYTHIA. BUT THESE VERTICES ARE NOT PASSED TO GEANT BECAUSE OF A 10**-16 LIFETIME CUT IN INTERFACE. ====================================================================== page 4 PROBLEMS AND ODDITIES CONTD. 8. IN HERWIG, OCCASIONALLY GET A RADIATED GAMMA FROM ELEMENTARY PROCESS (IN 4% OF TOP EVENTS). THIS GAMMA "DECAYS" TO SOME ENTITY (STATUS 157) WHICH THEN "DECAYS" TO THE SAME GAMMA. BUT THE MOTHER OF THAT ENTITY IS NOT THE INITIAL GAMMA. RESULT IS ABORT IN mc_event. I AVOID THESE ABORTS WITH A PATCH IN mc_event. ====================================================================== page 5 8 3 -6 5 6 0 0 9 3 24 7 0 0 0 10 3 5 7 0 0 0 11 3 -24 8 0 0 0 12 3 -5 8 0 0 0 13 3 -3 9 0 0 0 14 3 4 9 0 0 0 15 3 1 11 0 0 0 16 3 -2 11 0 0 0 17 2 -24 11 0 51 61 18 2 24 9 0 41 50 19 2 2 3 0 75 75 20 2 21 3 0 75 75 21 2 21 3 0 75 75 22 2 21 3 0 75 75 23 2 21 3 0 75 75 24 2 21 3 0 75 75 25 2 21 3 0 75 75 26 2 21 3 0 75 75 27 2 21 3 0 75 75 28 2 21 3 0 75 75 29 2 2101 1 0 75 75 35 2 5 10 0 97 97 36 2 -5 12 0 109 109 75 2 92 19 29 76 96 ======================================================================