HNL production vertex placement close to Target.z0

[anupama-reghunath]

Attached is the HNL production vertex from a signal simulation(HNL->rho+lepton, where the target.z0 = -58.865 (10,000 events). The production vertex always seems to be placed at z very close to target.z0. Given the statistics, shouldn't we be getting an exponential distribution for the HNL production vertex(z)?

[olantwin]

Could you please make a histogram comparing the weighted distribution of HNL decays for $\rho+\ell$ and $\mu+\pi$?

AFAIR it was possible to select the z range in which to generate HNL decays, or was this changes? At least in the acceptance studies I did years ago, they were generated only around the decay vessel.

[anupama-reghunath]

The reconstructed HNL candidate in these cases do decay generally within the decay vessel, but the point of HNL production ( HNLTrack StartZ) is what is at target.z0, In this context, would it also be reasonable to connect this to the fact that the IP is also always calculated wrt to the target.z0 as well?

[olantwin]

Oh, I think I completely misunderstood the issue, I was thinking about the decay vertex...
The production vertex of the HNL should hopefully be independent of the decay mechanism and indeed one would expect them to follow some decaying distribution + a prompt component