3
C... force particles to lie on the mass shell
4
C assume that phep(5) is the correct mass
5
C ignore particles which have already decayed
13
double precision msq,p4,newp,oldp,newroot,ms
16
if( isthep(i) .eq. 1 ) then
17
msq = phep(4,i)**2-phep(1,i)**2-phep(2,i)**2-phep(3,i)**2
18
p4 = phep(4,i)**2+phep(5,i)**2-msq
20
p4 = phep(5,i)**2+phep(1,i)**2+phep(2,i)**2+phep(3,i)**2