4 SUBROUTINE lu2ent(IP,KF1,KF2,PECM)
8 common/lujets/
n,
k(9000,5),
p(9000,5),
v(9000,5)
10 common/ludat1/mstu(200),paru(200),mstj(200),parj(200)
12 common/ludat2/kchg(500,3),pmas(500,4),parf(2000),vckm(4,4)
17 IF(mstu(12).GE.1) CALL
lulist(0)
19 IF(ipa.GT.mstu(4)-1) CALL
luerrm(21,
20 &
'(LU2ENT:) writing outside LUJETS memory')
23 IF(kc1.EQ.0.OR.kc2.EQ.0) CALL
luerrm(12,
24 &
'(LU2ENT:) unknown flavour code')
28 IF(mstu(10).EQ.1) pm1=
p(ipa,5)
29 IF(mstu(10).GE.2) pm1=
ulmass(kf1)
31 IF(mstu(10).EQ.1) pm2=
p(ipa+1,5)
32 IF(mstu(10).GE.2) pm2=
ulmass(kf2)
40 kq1=kchg(kc1,2)*isign(1,kf1)
41 kq2=kchg(kc2,2)*isign(1,kf2)
42 IF(kq1+kq2.NE.0.AND.kq1+kq2.NE.4) CALL
luerrm(2,
43 &
'(LU2ENT:) unphysical flavour combination')
50 IF(kq1.NE.0.AND.kq2.NE.0)
k(ipa,1)=2
55 IF(kq1.EQ.0.OR.kq2.EQ.0) CALL
luerrm(2,
56 &
'(LU2ENT:) requested flavours can not develop parton shower')
59 k(ipa,4)=mstu(5)*(ipa+1)
61 k(ipa+1,4)=mstu(5)*ipa
66 IF(pecm.LE.pm1+pm2) CALL
luerrm(13,
67 &
'(LU2ENT:) energy smaller than sum of masses')
68 pa=sqrt(
max(0.,(pecm**2-pm1**2-pm2**2)**2-(2.*pm1*pm2)**2))/
71 p(ipa,4)=sqrt(pm1**2+pa**2)
74 p(ipa+1,4)=sqrt(pm2**2+pa**2)