New problem with MMoffK+ spectrum difference between sig and bkgd [SOLVED]

See below.  Significant difference between Lambda mass from MMoffK+ when comparing signal and background.  Need to check raw MC generator.

Checking:

1. kL_phasesp_genr8.py.  Correctly assigning particle type -18 to all Lambdas (so that GEANT doesn't track/decay the Lambda).

LIGHTNING BOLT -- this is probably OK, the result of the KF trying to make the background events look like sl_mu events.  Check the pre-KF MMoffK+:

Yessss