1 SUBROUTINE PHOTWO(MODE)
2 C.----------------------------------------------------------------------
4 C. PHOTWO: PHOtos but TWO mothers allowed
6 C. Purpose: Combines two mothers into one in /PHOEVT/
7 C. necessary eg in case of g g (q qbar) --> t tbar
9 C. Input Parameters: Common /PHOEVT/ (/PHOCMS/)
11 C. Output Parameters: Common /PHOEVT/, (stored mothers)
13 C. Author(s): Z. Was Created at: 5/08/93
14 C. Last Update:10/08/93
16 C.----------------------------------------------------------------------
19 PARAMETER (NMXPHO=10000)
20 INTEGER IDPHO,ISTPHO,JDAPHO,JMOPHO,NEVPHO,NPHO
22 COMMON/PHOEVT/NEVPHO,NPHO,ISTPHO(NMXPHO),IDPHO(NMXPHO),
23 &JMOPHO(2,NMXPHO),JDAPHO(2,NMXPHO),PPHO(5,NMXPHO),VPHO(4,NMXPHO)
24 DOUBLE PRECISION BET(3),GAM
25 COMMON /PHOCMS/ BET,GAM
29 C logical IFRAD is used to tag cases when two mothers may be
30 C merged to the sole one.
31 C So far used in case:
32 C 1) of t tbar production
36 IFRAD=(IDPHO(1).EQ.21).AND.(IDPHO(2).EQ.21)
37 IFRAD=IFRAD.OR.(IDPHO(1).EQ.-IDPHO(2).AND.ABS(IDPHO(1)).LE.6)
39 & .AND.(ABS(IDPHO(3)).EQ.6).AND.(ABS(IDPHO(4)).EQ.6)
40 MPASQR= (PPHO(4,1)+PPHO(4,2))**2-(PPHO(3,1)+PPHO(3,2))**2
41 & -(PPHO(2,1)+PPHO(2,2))**2-(PPHO(1,1)+PPHO(1,2))**2
42 IFRAD=IFRAD.AND.(MPASQR.GT.0.0D0)
44 c.....combining first and second mother
46 PPHO(I,1)=PPHO(I,1)+PPHO(I,2)
48 PPHO(5,1)=SQRT(MPASQR)
49 c.....removing second mother,
55 C boosting of the mothers to the reaction frame not implemented yet.
56 C to do it in mode 0 original mothers have to be stored in new comon (?)
57 C and in mode 1 boosted to cms.