Result of the command grep "chiSq/nDof" *.out | grep -v "pValue = 0.000" > problem-histos.txt

1. We should increase the tensor probability from 10 to 20 for EvtSSD_DirectCP (e.g. for B+ -> f_2 pi).

2. The NaN values for EvtLb2Baryonlnu are occurring because it sets the spin density matrix components for the parent baryon using the momentum in the lab (mother) frame. If the parent baryon is the mother particle, then it has zero momentum and the cosTheta term (which divides by the momentum magnitude) becomes NaN. This could be resolved by only calculating cosTheta if the momentum is non zero, otherwise it will be initialised to zero:
   
   double cosTheta = pmag > 0.0 ? vector4P.get( 3 ) / pmag : 0.0;
   
   This removes the NaN values in the density matrix.

3. The probability distribution for EvtVtoSll has a very long tail going beyond the defined maximum of 10.0 and so we get many max probability warnings when the k2 variable is very small (<0.001). We would need to add some compensation method to avoid this problem.

Many of the zero nDof histograms in problem-histos.txt occur when there is only 1 bin filled (the others are empty), e.g. a constant PDG mass value with essentially zero width or a fixed momentum in a 2-body decay. So we could add a check for non-zero entries within the histogram range if nDof = 0 in addition to the chiSq/nDof number.

Just to link here the GitLab issue for EvtSSD_DirectCP

https://gitlab.cern.ch/evtgen/evtgen/-/issues/4