Common Blocks and Block Data

No input files are required by the generator and all parameters are given sensible values for the leptoquark. The generator makes use of the external common blocks /LUJETS/, /LEPTOU/, /HEPEVT/, /LUDAT1/, /LUDAT2/, /LUDAT4/, /PYPARS/, /AROPTN/, /HWBEAM/, /HWPROC/ /HWUNAM/, /HWEVNT/, /HWUPDT/,
/QUADRE/, /ANSWER/, /PRINT/ and /W50510/. There are two internal common blocks: /LQCOMM/ containing variables and /LQPARM/ containing parameters. The internal common block values have the following meaning and default values are shown as (D=...). Only variables with a default value may be changed by the user.

 
   		  		 IBEAM, IPROC, IDECAY,
                                     IFLAG, RADCOR, PARTSH

& ,                           		 PARTON, MEVENT, LQSEED,
                                     QLMASS, GL, GR, CLAMLG

& ,                           		 CLAMSQ, PHMASS, GAMLQ,
                                     XLQ, BEAPOL, TOXSEC

& ,                           		 TOXERR, SHAD, Z, PL,
                                     PP

 
IBEAM:     		 (D=-1) Beam type: 		 -1 = electron or

           		                     		 +1 = positron.

IPROC:     		 (D=0) Resonance type: 		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		    ,

           		                       		   ,

           		                       		   ,

           		                       		    or

           		                       		   .

IDECAY:    		 (D=1) Decay type: 		 0 = neutrino/anti-neutrino or

           		                   		 1 = electron/positron.

IFLAG:     		 (D=0) Event type: 		 0 = resonance with DIS
                                       and interference,

           		                   		 1 = DIS only,

           		                   		 2 = resonance only or

           		                   		 3 = interference only
                                       (not to be selected
                      by user).

RADCOR:    		 (D=0) QED corrections: 		 0 = Born
                                        cross-section or

           		                        		 1 = initial state
                       bremsstruhlung.

PARTSH:    		 (D=0) parton showers: 		 0 = no parton showers,

           		                       		 1 = final state parton
                                           showers using LUSHOW

           		                       		 2 = parton showers using
                                           ARIADNE or

           		                       		 3 = initial and final state parton
                                           showers using

           		                       		     HERWIG.

PARTON     		 parton distribution: 		 (D=40) PDF mode if
                                      PDFLIB used or

           		                      		 (D=1) MSTP(51) if
                                      PYSTFU used.

MEVENT:    		 Number of events generated.

LQSEED(2): 		 (D=9876,54321) Two random number seeds.

QLMASS:    		 (D=200.0) Resonance mass (GeV/c  ).

GL, GR:    		 (D=0.1,0.0) Left-handed and right-handed
              coupling strength for leptoquark

           		 (GL,GR = 0.3 is the electromagnetic coupling
              strength; ie.
                ).

CLAMLG:    		 (D=1000.0) Leptogluon coupling constant
              (GeV).

CLAMSQ:    		 (D=0.1) Squark coupling constant
              (  , including cosine of mixing
            angle,

           		   , for stop).

PHMASS:    		 (D=50.0) Photino mass (GeV/c  ).

GAMLQ:     		 Resonance full width (GeV/c  ).

XLQ:       		 Bjorken-x value of resonance peak
              (  ).

BEAPOL:    		 (D=0.0) Beam polarization (-1 to +1).

TOXSEC:    		 Total cross-section (pb).

TOXERR:    		 Error on total cross-section (pb).

SHAD:      		 Centre-of-mass energy squared,
                 (GeV  ).

Z:         		 Fraction of initial electron energy left after
              photon radiation,

           		   .

PL, PP:    		 Beam electron and proton 4-momentum
              (GeV/c  ).

PL and PP are initialized by the user via the argument list of the initialization routine LQINIT. GAMLQ, XLQ and SHAD are calculated directly in routine LQINIT. Variables IBEAM, IPROC, IDECAY, IFLAG, RADCOR, PARTSH, PARTON, LQSEED, QLMASS, GL, GR, CLAMLG, CLAMSQ, PHMASS and BEAPOL may be set by the user or the defaults used. TOXSEC and TOXERR are calculated by routine LQXSEC which is called by LQINIT at initialization. Z is filled on an event by event bases. Variable MEVENT should be updated by the user.

 
   		  		 Q, RL, R, VV, A, CONST,
                                     ZM, ZM2, ALPHAS, WM,
                    WM2

& ,                           		 XW, SIN2W, SPRDMP, 
                                     SPRDMG, IDGNPT

The above parameters are either calculated in the initialization routine LQSTAN or given default values by loading the block data subprogram LQDATA. The external block data PYDATA and LUDATA must also be loaded. The bock data ARDATA or HWUDAT should also be load if the ARIADNE or HERWIG options are chosen.