1
DOUBLE PRECISION FUNCTION DSIG2(PP,WGT,IMODE)
2
C ****************************************************
4
C Generated by MadGraph 5 v. 2.0.0.beta3, 2013-02-14
5
C By the MadGraph Development Team
6
C Please visit us at https://launchpad.net/madgraph5
8
C Process: g d~ > g g g d~ WEIGHTED=4
9
C Process: g u~ > g g g u~ WEIGHTED=4
10
C Process: g s~ > g g g s~ WEIGHTED=4
12
C RETURNS DIFFERENTIAL CROSS SECTION
14
C pp 4 momentum of external particles
15
C wgt weight from Monte Carlo
16
C imode 0 run, 1 init, 2 reweight,
17
C 3 finalize, 4 only PDFs
19
C Amplitude squared and summed
20
C ****************************************************
26
INCLUDE 'nexternal.inc'
27
INCLUDE 'maxconfigs.inc'
30
PARAMETER (CONV=389379.66*1000) !CONV TO PICOBARNS
32
PARAMETER (PI=3.1415926D0)
36
DOUBLE PRECISION PP(0:3,NEXTERNAL), WGT
41
INTEGER I,ITYPE,LP,IPROC
43
DOUBLE PRECISION SX2,UX2,DX2
44
DOUBLE PRECISION XPQ(-7:7),PD(0:MAXPROC)
45
DOUBLE PRECISION DSIGUU,R,RCONF
46
INTEGER LUN,ICONF,IFACT,NFACT
53
DOUBLE PRECISION ALPHAS2,REWGT,PDG2PDF
59
COMMON /SUBPROC/ IPSEL
60
C MINCFIG has this config number
61
INTEGER MINCFIG, MAXCFIG
62
COMMON/TO_CONFIGS/MINCFIG, MAXCFIG
63
INTEGER MAPCONFIG(0:LMAXCONFIGS), ICONFIG
64
COMMON/TO_MCONFIGS/MAPCONFIG, ICONFIG
65
C Keep track of whether cuts already calculated for this event
66
LOGICAL CUTSDONE,CUTSPASSED
67
COMMON/TO_CUTSDONE/CUTSDONE,CUTSPASSED
69
INTEGER SUBDIAG(MAXSPROC),IB(2)
70
COMMON/TO_SUB_DIAG/SUBDIAG,IB
77
DATA SX2,UX2,DX2/3*1D0/
84
C Set up process information from file symfact
87
OPEN(UNIT=LUN,FILE='../symfact.dat',STATUS='OLD',ERR=20)
89
READ(LUN,*,ERR=10,END=10) RCONF, IFACT
91
IF(ICONF.EQ.MAPCONFIG(MINCFIG))THEN
97
20 WRITE(*,*)'Error opening symfact.dat. No symmetry factor used.'
100
C Only run if IMODE is 0
101
IF(IMODE.NE.0.AND.IMODE.NE.4) RETURN
104
IF (ABS(LPP(IB(1))).GE.1) THEN
105
LP=SIGN(1,LPP(IB(1)))
106
G1=PDG2PDF(ABS(LPP(IB(1))),0*LP,XBK(IB(1)),DSQRT(Q2FACT(1)))
108
IF (ABS(LPP(IB(2))).GE.1) THEN
109
LP=SIGN(1,LPP(IB(2)))
110
SX2=PDG2PDF(ABS(LPP(IB(2))),-3*LP,XBK(IB(2)),DSQRT(Q2FACT(2)))
111
UX2=PDG2PDF(ABS(LPP(IB(2))),-2*LP,XBK(IB(2)),DSQRT(Q2FACT(2)))
112
DX2=PDG2PDF(ABS(LPP(IB(2))),-1*LP,XBK(IB(2)),DSQRT(Q2FACT(2)))
116
IPROC=IPROC+1 ! g d~ > g g g d~
118
PD(0)=PD(0)+DABS(PD(IPROC))
119
IPROC=IPROC+1 ! g u~ > g g g u~
121
PD(0)=PD(0)+DABS(PD(IPROC))
122
IPROC=IPROC+1 ! g s~ > g g g s~
124
PD(0)=PD(0)+DABS(PD(IPROC))
129
CALL SMATRIX2(PP,DSIGUU)
130
DSIGUU=DSIGUU*REWGT(PP)*NFACT
131
IF (DSIGUU.LT.1D199) THEN
132
C Select a flavor combination (need to do here for right sign)
135
DO WHILE (R.GT.0D0 .AND. IPSEL.LT.IPROC)
137
R=R-DABS(PD(IPSEL))/PD(0)
139
C Set sign of dsig based on sign of PDF and matrix element
140
DSIG2=DSIGN(PD(0)*CONV*DSIGUU,DSIGUU*PD(IPSEL))
142
WRITE(*,*) 'Error in matrix element'
146
IF(IMODE.EQ.0.AND.DABS(DSIG2).GT.0D0)THEN
147
C Call UNWGT to unweight and store events
148
CALL UNWGT(PP,DSIG2*WGT,2)