How to Use LUHADR

The LUHADR module has been completely rewritten except for its basic structure that LUHADR passes each color singlet system in the final state to LUFRAG to hadronize is preserved. As for the user interface, however, the new LUHADR module differs from the previous one only in the FT05 input stream. Nevertheless, we will show how to use LUHADR below from the beginning.

In FLANLI, invoke the description program for the LUHADR hadronizer

   CALL DSLHAD

after the event read or the SPRING section.

The FT05 input stream for the LUHADR module is for instance

@!
@!*************************************************
@! Input section for Lund hadronizer.
@!*************************************************
@!
LUND_FRAG
   MDCY 23 1 0  ! MDCY(23,1) switches off Z decay
   MDCY 24 1 0  ! MDCY(24,1) switches off W decay
   MDCY 33 1 0  ! MDCY(33,1) switches off Z" (used for LSP) decay
   JAK1      0  ! JAK1 (0 for all tau+ decay modes)
   JAK2      0  ! JAK2 (0 for all tau- decay modes)
   ITDKRC    1  ! ITDKRC (1 for decay RC on)
   KEYA1     1  ! switch for a1 decay treatment (1 for constant widths)
   IHLON     1  ! tau polarization: IHLON = (0,1) = (off,on)
   XK0DEC 0.001 ! soft/hard photon phase space separator
EXIT

where the MDCY setting should not be modified unless you know exactly what you are doing. When Spring:Parton_List contains W's or Z's together with their daughters, never modify it. The particle code 33 for Z" is internally used for the LSP whose particle code is 220000 in the JLC convention: set particle ID code to 220000 in Spring:Parton_List, when you store the LSP.

The remaining inputs are related to TAUOLA as explained in the previous chapter and can be modified: the decay mode selection capability and the polarization switch will be particularly useful.

These are all to use the new LUHADR program, if you need no new features such as polarized tau decays or parton-showering of color-non-singlet system. Those who want these new feature have to prepare Spring:Parton_List accordingly.