Hoi Ric,
discussions with Denis and Alessio have not solved my confusion about
your killing function.
I peeked into the gam lists and generator blocks of events with
K0s->pi0pi0 in the old MC. The wrong bumps do not have a truth-match
by virtue of the bug (I seem to remember this, and I have not found a
single counter example). So either they are merged with the correct
bump or we will never kill the proper one with the current setup.
If the bad photons are merged with the correct one (this can be
checked from the kinematics of the decay modulo resolutions since the
correct photons have the link back to the mothers), killing is -- on
an event by event basis -- not the right thing to do. Rescaling the
energy would seem more appropriate.
If they are not merged and the bad photons are still in the event, we
should be able to find the best match to the K0S decay from the
unmatched photons and throw out the correct ones. This amounts to the
same as what is done in VubRemoveOrphans. I guess it would be good to
understand why VubRemoveOrphans fails to remove them properly.
Cheers,
--U.
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