BES software note # 7 ___ ________ ____ _ _ EVENTGEN ________ A Guide to BES Event Generators Version 1.0 Prepared by WANG Taijie Mar 1989 Version 1.1 Updated by Derrick Kong May 1998 This note describes the event generators currently supported in the BES Monte Carlo (SOBER). EVENTGEN: Event generators Page 2 V1.1 13 May 1998 0 INTRODUCTION _ ____________ 0.1 Event Generator Function ___ _____ _________ ________ The monte carlo event generator is responsible for creating the 4-vectors for an event at the initial vertex. This includes the selection of particle Id's ,life times and resonance widths . The detailed information is contained in the SOBER common /EVENTT/. 0.2 Event Generator Protocol ___ _____ _________ ________ 0.2.1 Naming Convention _____ ______ __________ Event generators are assigned unique names and ID's of event types. The event type is read from the SOBCARD file via a EVT_TYPE card by subroutine MCARDS. The address of the corresponding subroutine of event generator is found and passed to the main program by a variable EVGADD in /MC3SYS/ to insure proper loading. The correspondences between IDs and names of event generators are as follows. Event-type Generator Name Event-type Generator Name ---------- -------------- ---------- -------------- 1 HOWL 16 P2BB 2 P2MUMU 17 DSSGEN 3 RHOPI 18 FFGEN 4 SAGERX 19 FSFGEN 5 TESTER 20 BHAGEN 6 P2EPEM 21 DDGEN 7 EPSCAT (BHABHA) 22 DSDGEN 8 FFF 23 MUGEN 9 DDPROD 24 GAMMA2 10 KSTARK 25 PPGEN 11 TAUPRD 26 RADMU 12 RADEE 27 FERMISV 13 RADGG 28 twogam 14 LUND 29 fssgen 15 UGNT 30 KORALBE 31 lund_charm 32-40 (unused) EVENTGEN: Event generators Page 3 V1.1 13 May 1998 0.2.2 Call Format _____ ____ ______ The event generator is called with the event number and a status flag. An initialization call and finalization call are also made. The call format is call CALLIT( , , ) where: = EVGADD = Event number. = Return status. This flag is always checked. It allows the routine to signal trouble and request graceful termination of the job. The expected values are: 1 => Normal finish 2 => Warning - something unexpected happened but execution may continue. 3 => Fatal Error - execution may not continue. Request graceful termination by the main program. 0.2.2.1 Normal Call _______ ______ ____ During the normal event loop the routine is called with a positive event number. The status flag will be set to 1 by the caller indicating success , so the routine need only set the flag to indicate a disaster. The status flag should be used to request termination rather than executing a FORTRAN 'STOP' from the routine directly. 0.2.2.2 Initialization Call _______ ______________ ____ The generator routine will be called once per run with = 0. This is allows the routine to perform any one time only or run by run initialization. E.g. reading a data file, defining model parameters. The intent is to eliminate the ad-hoc initialization via: EVENTGEN: Event generators Page 4 V1.1 13 May 1998 IF (EVENT.EQ.1) GO TO ... 0.2.2.3 Finalizing Call _______ __________ ____ The generator will be called once at the end of each run with = -1. This is to allow for such things as summary print outs or whatever is appropriate. The status flag will not be checked for this call. HOWL - PHASE SPACE DISTRIBUTIONS ____ _ _____ _____ _____________ 1 HOWL - PHASE SPACE DISTRIBUTIONS ____ _ _____ _____ _____________ 1.1 Weights ------- HOWL generates events according to phase space distributions. The events may be weighted or unweighted. Unweighted implies generating events with unit phase space weight which could require generating many events before finding one acceptable to the population. When generating unit weight events the program must establish the maximum possible event weight . This is done in a simple minded fashion by throwing N events and recording the maximum weight from the sample. The maximum weight is needed to determine if a particular event is admissable to the population of events. It is most effecient CPU-wise to generate weighted events. When generating weighted events one must respect the event weight when counting events. HOWL uses the SAGE package to generate event weights and distributions. 1.2 Event Definition _____ __________ The event which HOWL will generate is defined by the SOBER runcards CHRG_TRKS, NEUT_TRKS, DECAY , RESONANCE and GAMMA. CHRG_TRKS Card _________ ____ CHRG_TRKS [ .. ; where are signed real numbers indicating particle masses in GeV. The particle ID will be inferred from the mass by matching the mass value with known masses in /XMCHTY/. A match will be made if the masses agree to within 5 MeV. The tracks defined are assigned an ordinal number by the order in which they appear on the card. This is the official SOBER track number. EVENTGEN: Event generators Page 5 V1.1 13 May 1998 Example: -------- CHRG_TRKS +0.105 -0.105 ; will define 2 charged tracks with masses 0.105 Gev (i.e muons) The mu+ will be track 1 while the mu- will be track 2. Limitation: there may be no more than 60 tracks in an event. NEUT_TRKS Card _________ ____ NEUT_TRKS [ .. ; where is a signed real number indicating a neutral particle mass. A negative implies an antiparticle. Otherwise this card behaves just as the 'CHRG_TRKS' card. NOTE: A zero mass track will be identified as a neutrino. To define a photon one must also use the 'GAMMA' card defined below. DECAY Card _____ ____ DECAY TRK# LIFE_T ; where is the track number (integer) of a previously defined track and is the desired life time in seconds. The decay products must be specified immediately after with a 'CHRG_TRKS' and/or 'NEUT_TRKS' card(s). Tracks with a finite life time will be propagated in space. RESONANCE Card _________ ____ RESONANCE TRK# WIDTH ; This card works exactly like the 'DECAY' card above except it defines a resonance (i.e. a particle with finite width.) The width is specified in GeV. As in the 'DECAY' card the decay products must be specified by 'CHRG_TRKS' or 'NEUT_TRKS' card immediately following. Resonance tracks behave as zero life-time decayers; they do not propagate before decaying. EVENTGEN: Event generators Page 6 V1.1 13 May 1998 AUTODECAY Card _________ ____ AUTODECAY ; where is a list of 1 or more track numbers corresponding to previously defined tracks. The tracks listed will be decayed automatically by SOBER according to known branching ratios (as stored in routine DECAY). By default, particles defined via the CHRG or NEUT_TRKS cards will have infinite life times and thus will not decay in the detector. GAMMA Card _____ ____ GAMMA ; where is a list of 1 or more track numbers as above. The tracks listed will be identified as gammas rather than neutrinos which is the default. KSHORT And KLONG Cards ______ ___ _____ _____ The following three cards allow some flexibilty in the treatment of K0 decays depending on the specific application. KSHORTS ; KLONGS ; KSHORT_KLONG ; The KSHORTS card requests that all K0's be treated as Kshorts while the KLONGS will cause all K0's to be treated as Klongs. The KSHORT_KLONG card selects the default mode whereby K0's are treated as a 50% mixture of Ks,Kl on a track by track basis. 1.3 Howl Parameters ---- ---------- HOWL accepts 3 parameters which control the use of unweighted events. The parameters are communicated through the 'HOWL' runcard and stored in /CMODEL/. MPARAM(1) = Flag to indicate whether weighted/unweighted events are desired. If the value is 1 unweighted events will be generated. If the 0 weighted events are generated and the next 2 params are ignored. EVENTGEN: Event generators Page 7 V1.1 13 May 1998 MPARAM(2) = A count of the number of trial events to throw in order to establish a maximum weight for the event type. MPARAM(3) = The maximum number of attempts allowed for generating an acceptable event on any particular event. The program will quit if it can't generate an acceptable event after this many tries. The last two are only needed by unweighted generation. HOWL also maintains 2 counters in /CMODEL/ which are relevant when generating unweighted events. MPARAM(4) = Total number of trys needed to generate the current number of events. MPARAM(5) = Number of trys needed for the current event. P2MUMU - PSI -> MU MU ______ _ ___ __ __ __ 2 P2MUMU - PSI -> MU MU ------ - --- -- -- -- This routine generates mu pairs from Psi decay with a 1+cos^2 distribution. 2.1 P2MUMU Input ------ ----- P2MUMU receives its input from common /CMODEL/. The runcard 'XPARAM' fills these parameters. XPARAM(1) = Min-cos(theta) XPARAM(2) = Max-cos(theta). These two values define the Theta range over which mumu pairs will be restricted. RHOPI - PSI -> RHO PI EVENT GENERATOR _____ _ ___ __ ___ __ _____ _________ 3 RHOPI - PSI -> RHO PI EVENT GENERATOR _____ _ ___ __ ___ __ _____ _________ EVENTGEN: Event generators Page 8 V1.1 13 May 1998 3.1 General Features _______ ________ RHOPI generates the decay sequence: Psi -> pi+ pi- pi0 where one pair of the final state pions is resonant as a rho. The full decay distributions, representing the polarized production of the initial Psi are generated using a simple 2-body decay generator. When more than one mode is being generated, the relative populations are those expected for total I = 0 (i.e. equal numbers of all 3 modes). 3.2 Event Definition _____ __________ No event definition cards are required for this event generator. The actual mode generated is tagged in /MCMADE/ as the Event ID. It takes on the value 1,2,3 which are: 1 = rho0 pi0, 2 = rho- pi+, 3 = rho+ pi-. This may be used to isolate the properties of only one of the modes in a mixed sample. 3.3 RHOPI Parameters _____ __________ RHOPI accepts 1 parameter which controls the generation of the different final states (three different charge modes of the rho). MPARAM(1) = a bit mask to control generation of the different charged modes: 1 = rho0 pi0, 2 = rho- pi+, 4 = rho+ pi-. For example, the SOBCARD MPARAM(1) = '110'b ; / select rho+- pi-+ / would cause generation of the charged rho modes only (for investigating differential efficiencies). SAGERX - PSI RADIATIVE DECAY GENERATOR ______ _ ___ _________ _____ _________ 4 SAGERX - PSI RADIATIVE DECAY GENERATOR ______ _ ___ _________ _____ _________ 4.1 General Features _______ ________ SAGERX generates the decay sequence: Psi ->gamma + X, where X subsequently decays to two scalars/pseudoscalars. It is intended to generate the set of decays: Psi -> pi+ pi-, K+ K-, Kshort Kshort, Eta Eta... with X having any spin from 0 through 4 inclusive. EVENTGEN: Event generators Page 9 V1.1 13 May 1998 4.2 Event Definition _____ __________ A modified version of SAGE is used to generate the 4-vectors for the full final state. The 2 body decay psi-> gamma + X and the decay X -> S + S are generated with the full (theta,phi) angular distributions in their helicity frames. All subsequent decays (e.g for eta -> pi+ pi- pi0) are generated via pure phase space using the SAGE routine GOGEN. The final state for the event to be generated is specified by using HOWL cards CHRG_TRK, NEUT_TRK, RESONANCE, etc. An example is Kshort Kshort: NEUT_TRKS 0.0 2.220 ; GAMMA 1 ; RESONANCE trk# 2 width = .001 ; NEUT_TRKS = 0.498 0.498 ; DECAY trk# 3 life = 0.89e-10 ; CHRG_TRKS = -0.139 0.139 ; DECAY trk# 4 life = 0.89e-10 ; CHRG_TRKS = -0.139 0.139 ; 4.3 SAGERX Parameters ______ __________ SAGERX accepts 2 parameters which control the use of unweighted events. The parameters are communicated through the /CMODEL/ common. MPARAM(2) = Flag to indicate whether weighted/unweighted events are desired. If the value is 0 weighted events will be generated. If the value is greater than zero it is used as a count for the number of events to be generated during initialization in order to find a MAXWT for generating unweighted events. MPARAM(3) = The maximum number of attempts allowed for generating an acceptable event on any particular event. The program will quit if it can't generate an acceptable event after this many tries. SAGERX also accepts parameters to specify the details of the decay angular distributions. MPARAM(1) = J of the X particle which is produced initially. Values for J which are currently implemented are: J= 0,1,2,3,4. XPARAM(1) = first model dependent parameter. For J=0 this is the C 2 value of ALPHA in the angular distribution 1+ALPHA COS(theta gamma)2 which should be 1 for true J=0. For J greater than 0 this is the x parameter, namely the ratio of the helicity one to the helicity zero amplitude. EVENTGEN: Event generators Page 10 V1.1 13 May 1998 XPARAM(2) = second model dependent parameter. This parameter is only required for J greater than 1, in which case it is the y parameter, namely the ratio of the helicity two to the helicity zero amplitude. An example of the use of these parameters follows: MPARAM(1) = 2 ; / spin 2 model / MPARAM(2) = 100 ; / number of evts for MAXWT / MPARAM(3) = 50 ; / number of tries/event / XPARAM(1) = 1.00, 0.50 ; / x and y helicity parameters / TESTER - 4-VECTOR GENERATOR ______ _ ________ _________ 5 TESTER - 4-VECTOR GENERATOR ______ _ ________ _________ TESTER is a simple 4-vector generator. It generates tracks of a specfied momentum and type over a selectable solid angle. The primary use of TESTER has been for developing and debugging Monte Carlo routines. It may also be useful for determining acceptances. TESTER does not use the beam energy, hence it may be left uninitialized. 5.1 Tester Input ______ _____ TESTER recieves its input from common /CMODEL/ . The runcard 'MPARAM' and 'XPARAM' fills these parameters. The format is as follows; MPARAM(2) = Track ID a la /XMCHTY/ MPARAM(3) = Track charge (+1,0,-1) MPARAM(4) = Number of tracks to generate. MPARAM(5) = Decay flag. If 0 the tracks will be decayed automatically via routine DECAY. If non-zero the tracks will not decay. EVENTGEN: Event generators Page 11 V1.1 13 May 1998 XPARAM(1) = Min-cos(theta) XPARAM(2) = Max-cos(theta) . These two values define the Theta range over which tracks will be generated. XPARAM(3) = P , Track momentum in GeV. XPARAM(4) = Phi-min in radians XPARAM(5) = Phi-max in radians. The phi region will be restricted to XPARAM(4):XPARAM(5) only if XPARAM(5) > 0 XPARAM(6) = Delta_P. If this value is greater than 0, tracks will be generated with a uniform momentum distribution of P-delta_P to P+delta_P . If zero all tracks will have the same momentum. P2EPEM - PSI -> E+ E- ______ _ ___ __ __ __ 6 P2EPEM - PSI -> E+ E- ______ _ ___ __ __ __ This routine generates e+e- pairs from Psi decay with a 1+cos^2 distribution. 6.1 P2EPEM Input ______ _____ P2EPEM receives its input from common /CMODEL/. The runcard 'XPARAM' fills these parameters. XPARAM(1) = Min-cos(theta) XPARAM(2) = Max-cos(theta). These two values define the Theta range over which e+e- pairs will be restricted. EVENTGEN: Event generators Page 12 V1.1 13 May 1998 EPSCAT -- BHABHA SCATTERING ______ __ ______ __________ 7 EPSCAT -- BHABHA SCATTERING ______ __ ______ __________ This routine generates e+e- pairs with an angular distribution of Bhabha scattering. There is no input parameters needed. The solid angles of e+e- pairs are restricted by cuts: COS(177 dgr) < COSTHT < COS(3 dgr) -.9986 < COSTHT < .9986 FFF - FIELD-FEYNMAN FRAGMENTATION ___ _ _____________ _____________ 8 FFF - FIELD-FEYNMAN FRAGMENTATION ___ _ _____________ _____________ 8.1 General Features _______ ________ The FFF model is the abbreviation for Field-Feynman Fragmentation model. The basic principle is to generate e+e- --> q q(bar) pairs and then fragment the q and q(bar) separately into hadron jets. This model also contains e+e- --> tau pairs due to the fact that tau pair events are rather difficult to distinguish from hadronic events at BEPC energy. The kernel of the model is at how to turn quarks into jets. qq(bar) pairs are continuously pulled out of the vacuum and q(bar) combines with the quark left from previous generation to form a meson while the new quark q carries on the fragmentation chain. This procedure is continued until the last quark qn does not have enough energy to make more particles. The Q(bar) jet will fragment similarly and conservation of flavour,charge,E,P are imposed at the end of the event. 8.2 FFF Input ___ _____ The special FFF parameters in /CMODEL/ are defined as follow: Default MPARAM(4) = ID OF HEAVIEST PRIMARY QUARK 4 e.g. 4 means udsc 2 means ud only -4 means charm only (new) MPARAM(5) = 0 No Tau pair events 1 1 Tau pairs as well as hadronic events 2 Tau pairs only MPARAM(6) = 0/1 E,P CONSERVATION ON/OFF 0 MPARAM(7) = 3/ELSE LUND/MK3 RADIATIVE CORRECTION 3 Event quark angular distribution: 1 + ALPH COS(theta)2- Polsq ALPH sin(theta)2 COS(2phi) EVENTGEN: Event generators Page 13 V1.1 13 May 1998 XPARAM(2) = ALPH in angular distribution formula 1.0 XPARAM(13)= BEAM POLARISATION Pe+Pe- = polsq 0.0 XPARAM(3) = PROB. TO GET S QUARK FROM SEA 0.1 XPARAM(4) = PROB. TO GET C QUARK FROM SEA 0.0 XPARAM(5) = PTRMS = sigma_q (Pt Gaussian) 0.35 XPARAM(6) = VECTOR PARTICLE FRACTION (UDS) 0.2 XPARAM(7) = VECTOR PARTICLE FRACTION (CHARM) 0.8 LIGHT FLAVOUR SPLITTING FUNCTION: F(X) = (1-A) + A (1-X)N /(N+1) XPARAM(8) = POWER OF (1-X) IN SPLITTING FUNCTION 2.0 XPARAM(9) = A IN SPLITTING FUNCTION 0.77 CHARM SPLITTING FUNCTION: F(X) = FLAT if Epsilon_c < 0 = Peterson function if 0 <= Epsilon_c <= 1 = Delta function at z=1 if Epsilon_c > 1 XPARAM(10) = Epsilon_c 0.05 XPARAM(11) = STRONG INTERACTION ENHANCEMENT 1.15 FACTOR FOR e+e- --> qq(bar) w.r.t. QED DDPROD - D PRODUCTION ______ _ _ __________ 9 DDPROD - D PRODUCTION ______ _ _ __________ DDPROD generates DDbar pairs with the correct angular distribution and with specified ratios of charged to neutral and D to p D production. The decays of the D's themselves are handled by the general purpose decay routine DECAY. The DDPROD runcard selects the a levels of D to D and charged/neutral fractions. The input values are store in /CMODEL/. XPARAM(1) = Charged fraction of DDbar production (inclusive) XPARAM(2) = Neutral fraction of DDbar production (inclusive) EVENTGEN: Event generators Page 14 V1.1 13 May 1998 XPARAM(3) = Fraction charged production in DD mode XPARAM(4) = Fraction charged production in DD+DD mode XPARAM(5) = Fraction charged production in DD mode XPARAM(6) = Fraction neutral production in DD mode XPARAM(7) = Fraction neutral production in DD+DD mode XPARAM(8) = Fraction neutral production in DD mode The following relations must be true: XPARAM(1) + XPARAM(2) = 1.0 XPARAM(3)+XPARAM(4)+XPARAM(5) = 1.0 XPARAM(6)+XPARAM(7)+XPARAM(8) = 1.0 KSTARK - PSI -> KSTAR K EVENT GENERATOR ______ _ ___ __ _____ _ _____ _________ 10 KSTARK - PSI -> KSTAR K EVENT GENERATOR ______ _ ___ __ _____ _ _____ _________ 10.1 General Features _______ ________ KSTARK generates the decay sequence: Psi ->K Kbar pi where one of the K pi pairs in the final state is resonant as a Kstar. The full decay distributions, representing the polarized production of the initial Psi are generated using a simple 2-body decay generator. When more than one mode is being generated, the relative populations are those expected for total I = 0. Any combination of the modes measurable in BES may be generated. 10.2 Event Definition _____ __________ No event definition cards are required for this event generator. The actual mode generated is tagged in /MCMADE/ as the Event ID. It takes on the value 1-6 which are: 1 = K- K+ -> K- Pi0 2 = K+ K- -> K+ Pi0 3 = K- K+ -> K0 Pi- 4 = K+ K- -> K0 Pi+ 5 = K0 K0 -> K+ Pi- 6 = K0 K0 -> K- Pi+ EVENTGEN: Event generators Page 15 V1.1 13 May 1998 This flag may be used to isolate the properties of only one of the modes in a mixed sample. Note that all of the K0 generated are actually Kshort which then decay to pi+ pi-, and these additional factors are taken into account for the relative branching ratios of the different modes. 10.3 KSTARK Parameters ______ __________ KSTARK accepts 1 parameter which controls the generation of the different final states (the six modes mentioned above). MPARAM(1) = a bit mask to control generation of the different charged modes, the bits correspond to the mode numbers mentioned above. For example, the SOBCARD MPARAM(1) = '111100'b ; / select modes 3,4,5,6 / would cause generation of the four modes above which contain Kshorts. GENERATORS 11 TO 30 ---------- -- -- -- Please see the source code for the individual generators as to their use, limitations, parameters, etc. FSSGEN - Ds*~Ds* PRODUCTION -------------------------- 29 FSSGEN - Ds*~Ds* PRODUCTION ---------------------- FSSGEN generates Ds*Ds*bar pairs with the correct angular distribution and with specified ratios of Ds* to (PV)Ds+GAMMA and (PP)Ds+PI0 production. The decays of the Ds' themselves are handled by the general purpose decay routine DECAY. The FSSGEN runcard selects levels of Ds to D and charged/neutral fractions. The input values are store in /CMODEL/. MParams: 1 Decay mode of first Ds* (DMODS1) 2 Decay mode of second Ds* (DMODS2) 3 Decay mode of Ds from first Ds* (DMODE1) 4 Decay mode of Ds from second Ds* (DMODE2) DMODS1 IS SET BY THE GASP CARD MPARAM(1) DMODS2 IS SET BY THE GASP CARD MPARAM(2) DMODE1 IS SET BY THE GASP CARD MPARAM(3) DMODE2 IS SET BY THE GASP CARD MPARAM(4) MPARAM(I)=1000 will decay to all of possible channels according their BR.(PDG) K0DK1 AND K0DK2 ARE FLAGS INDICATING HOW K0'S ARE TO BE DECAYED. MPARAM(3) < 0 K0 from the D decays to pi+ pi- in 100%. So Klong after sampling is forced to decay to pi+pi- in K0DK.FOR. MPARAM(3) > 0 K0 from the D assigned to be Kshort or Klong, then Kshort decays in BR by DECAY.FOR. - MPARAM(4) is same as MPARAM(3). LUND_CHARM -- A General Generator --------------------------------- 31 LUND_CHARM -- A General Generator --------------------------------- 31.1 LUND_CHARM generates RESONANCE or CONTINUUM events, depended on the Ecm energy or a SOBER CARD. Following are the ways how to generate those events. (A) Generate Charmonium RESONANCE events: J/psi-->Hadrons Ecm=3.0969+-0.0002GeV, or Ecm=3.096+-0.0001GeV psi(2S) --> hadrons Ecm=3.686+-0.0002 GeV (B) Generate CONTINUUM energy reion events: e+e- --> gamma* --> hadrons 2 GeV4.5 GeV call LUND (C) Generate CONTINUUM energy reion events: e+e- --> gamma* --> hadrons MPARAM(1) = 1000, forced to call LUND for continuum energy hadron decay at any Ecm. (D) Generate events mixed with CONTINUUM and Charm mesons RESONANCE: e+e- --> gamma* --> hadrons 3.726 GeV < Ecm <4.5 GeV call LUND(u,d,s quark only) and mixing D mesons with Eichten model. 31.2 General Features _______ ________ (1) It can reproduce most main Br. of J/psi and psi(2S) decay modes. (2) Many event shape distributions are compared with BES data, and they consist with data well, such as Nch, KNO, Xp, Y, eta, Pt, Spherier, Thrust, Obl, Apl, cos(tht), phi, ... (3) The detail of this generator can be found from the Proc. of BES'99 (4) make particle ID match between SOBER and jetset74. (5) Let particle decay in the beam pipe. (6) check if a particle which SOBER unincluded, run again. (7) LULIST1, modified from jetset7.4's LULIST for there is a same name subroutine in the BESLIB kroalb.f. (8) Wiggle EBEAM is by a Sober card 'sig_bm SIGEBM'. (9) Related subroutines are as follows lucharm.f for J/psi and psi(2S) decay |-->luexec1.f-->ludecy1-->luonia1(rgg/ggg decay) (10) Leptons and transition modes of J/psi decay were input by PDG(98) (11) Leptons and transition modes of psi(2S) decay were input by PDG(96) (12) qq~ and (gamma gg)/ggg hadronization are handled by Jetset7.4. 31.3 Final particles of the event are selected and output by following SOBER CARDS (i) Defult Output MODE: decay to all of possible modes SOBER CARDS: MPARAM(1) = 0 (Defult card), or No ANY Mparam card. (ii) Output MODE1: Particle(1),Particle(2)..., Particle(n) SOBER CARDS: MPARAM(1) = 1, N,part1_ID,part1_Charge,part2_ID,part2_charge,.... | | Where: | N = Number. of final particles(stable), Decay modes 1 = stable final particles part_ID=ID of final particles in xmchty.inc for Example: gamma=1,e=2,mu=3,pi=4,K=5,p=6... part_Charge= Charge of final particle. (iii) Output MODE2: P1(unstable),P2(unstable)..., Pn(unstable) SOBER CARDS: MPARAM(1) = 2, N,part1_ID,part2_ID,,.... | | Where: | N = Number of final particles(unstable), Decay modes 2 = resonance of 1st decay level part_ID=ID of final particle in Jetset7.4 for Example:gamma=22,e+-=+-11,mu+-=+-133 pi+-=+-211,pi0=111, K+-=321,K0/K0~=311/-311 ... (iv) Output Mode3: P1(unstable),P2(unstable)...Pn(unstable)+X Sober CARDS: MPARAM(1) = 3, N,part1_ID,part2_ID,,.... | | Where: | N = Number of unstable particles, Decay modes 3 = unstable particles of 1st decay level + others part_ID=ID of unstable particle in the Jetset7.4 EVENTGEN: Event generators Page 16 V1.1 13 May 1998 CONTENTS 0.0.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.0.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.0.0.0.3 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 HOWL - PHASE SPACE DISTRIBUTIONS . . . . . . . . . . 4 1.1 Weights . . . . . . . . . . . . . . . . . . . . . 4 1.2 Event Definition . . . . . . . . . . . . . . . . . 4 1.2.0.0.1 CHRG_TRKS Card . . . . . . . . . . . . . . . . . . 4 1.2.0.0.2 NEUT_TRKS Card . . . . . . . . . . . . . . . . . . 5 1.2.0.0.3 DECAY Card . . . . . . . . . . . . . . . . . . . . 5 1.2.0.0.4 RESONANCE Card . . . . . . . . . . . . . . . . . . 5 1.2.0.0.5 AUTODECAY Card . . . . . . . . . . . . . . . . . . 6 1.2.0.0.6 GAMMA Card . . . . . . . . . . . . . . . . . . . . 6 1.2.0.0.7 KSHORT And KLONG Cards . . . . . . . . . . . . . . 6 1.3 Howl Parameters . . . . . . . . . . . . . . . . . 6 1.3.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.0.0.3 . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.0.0.4 . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.0.0.5 . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 P2MUMU - PSI -> MU MU . . . . . . . . . . . . . . . 7 2.1 P2MUMU Input . . . . . . . . . . . . . . . . . . . 7 2.1.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 RHOPI - PSI -> RHO PI EVENT GENERATOR . . . . . . . 7 3.1 General Features . . . . . . . . . . . . . . . . . 8 3.2 Event Definition . . . . . . . . . . . . . . . . . 8 3.3 RHOPI Parameters . . . . . . . . . . . . . . . . . 8 3.3.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . 8 4 SAGERX - PSI RADIATIVE DECAY GENERATOR . . . . . . . 8 4.1 General Features . . . . . . . . . . . . . . . . . 8 4.2 Event Definition . . . . . . . . . . . . . . . . . 9 4.3 SAGERX Parameters . . . . . . . . . . . . . . . . 9 4.3.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.0.0.3 . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.0.0.4 . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.0.0.5 . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.0.0.6 . . . . . . . . . . . . . . . . . . . . . . . . 10 4.3.0.0.7 . . . . . . . . . . . . . . . . . . . . . . . . 10 5 TESTER - 4-VECTOR GENERATOR . . . . . . . . . . . 10 5.1 Tester Input . . . . . . . . . . . . . . . . . . 10 5.1.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1.0.0.3 . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1.0.0.4 . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1.0.0.5 . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.0.0.6 . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.0.0.7 . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.0.0.8 . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.0.0.9 . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.0.0.10 . . . . . . . . . . . . . . . . . . . . . . . 11 EVENTGEN: Event generators Page 17 V1.1 13 May 1998 6 P2EPEM - PSI -> E+ E- . . . . . . . . . . . . . . 11 6.1 P2EPEM Input . . . . . . . . . . . . . . . . . . 11 6.1.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . 11 7 EPSCAT -- BHABHA SCATTERING . . . . . . . . . . . 12 8 FFF - FIELD-FEYNMAN FRAGMENTATION . . . . . . . . 12 8.1 General Features . . . . . . . . . . . . . . . . 12 8.2 FFF Input . . . . . . . . . . . . . . . . . . . 12 9 DDPROD - D PRODUCTION . . . . . . . . . . . . . . 13 9.0.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . . 13 9.0.0.0.2 . . . . . . . . . . . . . . . . . . . . . . . . 14 9.0.0.0.3 . . . . . . . . . . . . . . . . . . . . . . . . 14 10 KSTARK - PSI -> KSTAR K EVENT GENERATOR . . . . . 14 10.1 General Features . . . . . . . . . . . . . . . . 14 10.2 Event Definition . . . . . . . . . . . . . . . . 14 10.3 KSTARK Parameters . . . . . . . . . . . . . . . 15 10.3.0.0.1 . . . . . . . . . . . . . . . . . . . . . . . 15 11 GENERATORS 11 TO 30 . . . . . . . . . . . . . . . 15 29 FSSGEN - Ds*Ds* EVENT GENERATOR 31 LUND_CHARM - A GENERAL EVENT GENERATOR FOR BES