3 C*********************************************************************
5 SUBROUTINE LUBOEI_HIJING(NSAV)
7 C...Purpose: to modify event so as to approximately take into account
8 C...Bose-Einstein effects according to a simple phenomenological
10 IMPLICIT DOUBLE PRECISION(D)
11 #include "lujets_hijing.inc"
12 #include "ludat1_hijing.inc"
13 DIMENSION DPS(4),KFBE(9),NBE(0:9),BEI(100)
14 DATA KFBE/211,-211,111,321,-321,130,310,221,331/
16 C...Boost event to overall CM frame. Calculate CM energy.
17 IF((MSTJ(51).NE.1.AND.MSTJ(51).NE.2).OR.N-NSAV.LE.1) RETURN
21 IF(K(I,1).LE.0.OR.K(I,1).GT.10) GOTO 120
23 110 DPS(J)=DPS(J)+P(I,J)
25 CALL LUDBRB_HIJING(0,0,0.,0.,-DPS(1)/DPS(4),-DPS(2)/DPS(4),
29 130 IF(K(I,1).GE.1.AND.K(I,1).LE.10) PECM=PECM+P(I,4)
31 C...Reserve copy of particles by species at end of record.
33 DO 160 IBE=1,MIN(9,MSTJ(51))
36 IF(K(I,2).NE.KFBE(IBE)) GOTO 150
37 IF(K(I,1).LE.0.OR.K(I,1).GT.10) GOTO 150
38 IF(NBE(IBE).GE.MSTU(4)-MSTU(32)-5) THEN
40 $ ,'(LUBOEI_HIJING:) no more memory left in LUJETS_HIJING')
50 C...Tabulate integral for subsequent momentum shift.
51 DO 210 IBE=1,MIN(9,MSTJ(51))
52 IF(IBE.NE.1.AND.IBE.NE.4.AND.IBE.LE.7) GOTO 180
53 IF(IBE.EQ.1.AND.MAX(NBE(1)-NBE(0),NBE(2)-NBE(1),NBE(3)-NBE(2)).
55 IF(IBE.EQ.4.AND.MAX(NBE(4)-NBE(3),NBE(5)-NBE(4),NBE(6)-NBE(5),
56 &NBE(7)-NBE(6)).LE.1) GOTO 180
57 IF(IBE.GE.8.AND.NBE(IBE)-NBE(IBE-1).LE.1) GOTO 180
58 IF(IBE.EQ.1) PMHQ=2.*ULMASS_HIJING(211)
59 IF(IBE.EQ.4) PMHQ=2.*ULMASS_HIJING(321)
60 IF(IBE.EQ.8) PMHQ=2.*ULMASS_HIJING(221)
61 IF(IBE.EQ.9) PMHQ=2.*ULMASS_HIJING(331)
62 QDEL=0.1*MIN(PMHQ,PARJ(93))
63 IF(MSTJ(51).EQ.1) THEN
64 NBIN=MIN(100,NINT(9.*PARJ(93)/QDEL))
65 BEEX=EXP(0.5*QDEL/PARJ(93))
66 BERT=EXP(-QDEL/PARJ(93))
68 NBIN=MIN(100,NINT(3.*PARJ(93)/QDEL))
72 BEI(IBIN)=QDEL*(QBIN**2+QDEL**2/12.)/SQRT(QBIN**2+PMHQ**2)
73 IF(MSTJ(51).EQ.1) THEN
75 BEI(IBIN)=BEI(IBIN)*BEEX
77 BEI(IBIN)=BEI(IBIN)*EXP(-(QBIN/PARJ(93))**2)
79 170 IF(IBIN.GE.2) BEI(IBIN)=BEI(IBIN)+BEI(IBIN-1)
81 C...Loop through particle pairs and find old relative momentum.
82 180 DO 200 I1M=NBE(IBE-1)+1,NBE(IBE)-1
84 DO 200 I2M=I1M+1,NBE(IBE)
86 Q2OLD=MAX(0.,(P(I1,4)+P(I2,4))**2-(P(I1,1)+P(I2,1))**2-(P(I1,2)+
87 &P(I2,2))**2-(P(I1,3)+P(I2,3))**2-(P(I1,5)+P(I2,5))**2)
90 C...Calculate new relative momentum.
91 IF(QOLD.LT.0.5*QDEL) THEN
93 ELSEIF(QOLD.LT.(NBIN-0.1)*QDEL) THEN
96 RINP=(RBIN**3-IBIN**3)/(3*IBIN*(IBIN+1)+1)
97 QMOV=(BEI(IBIN)+RINP*(BEI(IBIN+1)-BEI(IBIN)))*
98 & SQRT(Q2OLD+PMHQ**2)/Q2OLD
100 QMOV=BEI(NBIN)*SQRT(Q2OLD+PMHQ**2)/Q2OLD
102 Q2NEW=Q2OLD*(QOLD/(QOLD+3.*PARJ(92)*QMOV))**(2./3.)
104 C...Calculate and save shift to be performed on three-momenta.
105 HC1=(P(I1,4)+P(I2,4))**2-(Q2OLD-Q2NEW)
106 HC2=(Q2OLD-Q2NEW)*(P(I1,4)-P(I2,4))**2
107 HA=0.5*(1.-SQRT(HC1*Q2NEW/(HC1*Q2OLD-HC2)))
109 PD=HA*(P(I2,J)-P(I1,J))
111 190 P(I2M,J)=P(I2M,J)-PD
115 C...Shift momenta and recalculate energies.
116 DO 230 IM=NBE(0)+1,NBE(MIN(9,MSTJ(51)))
119 220 P(I,J)=P(I,J)+P(IM,J)
120 230 P(I,4)=SQRT(P(I,5)**2+P(I,1)**2+P(I,2)**2+P(I,3)**2)
122 C...Rescale all momenta for energy conservation.
126 IF(K(I,1).LE.0.OR.K(I,1).GT.10) GOTO 240
128 PQS=PQS+P(I,5)**2/P(I,4)
130 FAC=(PECM-PQS)/(PES-PQS)
132 IF(K(I,1).LE.0.OR.K(I,1).GT.10) GOTO 260
134 250 P(I,J)=FAC*P(I,J)
135 P(I,4)=SQRT(P(I,5)**2+P(I,1)**2+P(I,2)**2+P(I,3)**2)
138 C...Boost back to correct reference frame.
139 CALL LUDBRB_HIJING(0,0,0.,0.,DPS(1)/DPS(4),DPS(2)/DPS(4),DPS(3)