1 SUBROUTINE PHOBOS(IP,PBOOS1,PBOOS2,FIRST,LAST)
2 C.----------------------------------------------------------------------
4 C. PHOBOS: PHOton radiation in decays BOoSt routine
6 C. Purpose: Boost particles in cascade decay to parent rest frame
7 C. and boost back with modified boost vector.
9 C. Input Parameters: IP: pointer of particle starting chain
11 C. PBOOS1: Boost vector to rest frame,
12 C. PBOOS2: Boost vector to modified frame,
13 C. FIRST: Pointer to first particle to be boos-
15 C. LAST: Pointer to last particle to be boos-
18 C. Output Parameters: Common /PH_HEPEVT/.
20 C. Author(s): B. van Eijk Created at: 13/02/90
21 C. Z. Was Last Update: 16/11/93
23 C.----------------------------------------------------------------------
25 DOUBLE PRECISION BET1(3),BET2(3),GAM1,GAM2,PB,DATA
26 INTEGER I,J,FIRST,LAST,MAXSTA,NSTACK,IP
27 PARAMETER (MAXSTA=10000)
29 REAL*8 PBOOS1(5),PBOOS2(5)
31 PARAMETER (NMXHEP=10000)
32 INTEGER IDHEP,ISTHEP,JDAHEP,JMOHEP,NEVHEP,NHEP
34 COMMON/PH_HEPEVT/NEVHEP,NHEP,ISTHEP(NMXHEP),IDHEP(NMXHEP),
35 &JMOHEP(2,NMXHEP),JDAHEP(2,NMXHEP),PHEP(5,NMXHEP),VHEP(4,NMXHEP)
36 IF ((LAST.EQ.0).OR.(LAST.LT.FIRST)) RETURN
39 BET1(J)=-PBOOS1(J)/PBOOS1(5)
40 10 BET2(J)=PBOOS2(J)/PBOOS2(5)
41 GAM1=PBOOS1(4)/PBOOS1(5)
42 GAM2=PBOOS2(4)/PBOOS2(5)
44 C-- Boost vector to parent rest frame...
46 PB=BET1(1)*PHEP(1,I)+BET1(2)*PHEP(2,I)+BET1(3)*PHEP(3,I)
47 IF (JMOHEP(1,I).EQ.IP) THEN
49 30 PHEP(J,I)=PHEP(J,I)+BET1(J)*(PHEP(4,I)+PB/(GAM1+1.D0))
50 PHEP(4,I)=GAM1*PHEP(4,I)+PB
52 C-- ...and boost back to modified parent frame.
53 PB=BET2(1)*PHEP(1,I)+BET2(2)*PHEP(2,I)+BET2(3)*PHEP(3,I)
55 40 PHEP(J,I)=PHEP(J,I)+BET2(J)*(PHEP(4,I)+PB/(GAM2+1.D0))
56 PHEP(4,I)=GAM2*PHEP(4,I)+PB
57 IF (JDAHEP(1,I).NE.0) THEN
60 C-- Check on stack length...
61 IF (NSTACK.GT.MAXSTA) THEN
63 CALL PHOERR(7,'PHOBOS',DATA)
71 C-- Now go one step further in the decay tree...
72 FIRST=JDAHEP(1,STACK(NSTACK))
73 LAST=JDAHEP(2,STACK(NSTACK))