dc/d8b/pytaud_8f_source.html

C*********************************************************************


C...PYTAUD

C...Dummy routine, to be replaced by user, to handle the decay of a

C...polarized tau lepton.

C...Input:

C...ITAU is the position where the decaying tau is stored in /PYJETS/.

C...IORIG is the position where the mother of the tau is stored;

C...     is 0 when the mother is not stored.

C...KFORIG is the flavour of the mother of the tau;

C...     is 0 when the mother is not known.

C...Note that IORIG=0 does not necessarily imply KFORIG=0;

C...     e.g. in B hadron semileptonic decays the W  propagator

C...     is not explicitly stored but the W code is still unambiguous.

C...Output:

C...NDECAY is the number of decay products in the current tau decay.

C...These decay products should be added to the /PYJETS/ common block,

C...in positions N+1 through N+NDECAY. For each product I you must

C...give the flavour codes K(I,2) and the five-momenta P(I,1), P(I,2),

C...P(I,3), P(I,4) and P(I,5). The rest will be stored automatically.


      SUBROUTINE pytaud(ITAU,IORIG,KFORIG,NDECAY)


C...Double precision and integer declarations.

      IMPLICIT DOUBLE PRECISION(a-h, o-z)

      IMPLICIT INTEGER(i-n)

      INTEGER pyk,pychge,pycomp

C...Commonblocks.

      common/pyjets/n,npad,k(4000,5),p(4000,5),v(4000,5)

      common/pydat1/mstu(200),paru(200),mstj(200),parj(200)

      SAVE /pyjets/,/pydat1/


C...Stop program if this routine is ever called.

C...You should not copy these lines to your own routine.

      ndecay=itau+iorig+kforig

      WRITE(mstu(11),5000)

      CALL pystop(10)


C...Format for error printout.

 5000 FORMAT(1x,'Error: you did not link your PYTAUD routine ',

     &'correctly.'/1x,'Dummy routine in PYTHIA file called instead.'/

     &1x,'Execution stopped!')


      RETURN

      END