How does lifetime affect HSN event probability at MicroBooNE

How does lifetime affects events probability? (e.g. if all neutrino have same lifetime, lower momentum neutrino should be more likely to decay since they have more time in their reference frame to decay).

That's taken care at the flux stage. The flux provided to the larsoft generator is already weighted by decay probability (which at first order, just goes like 1/p, where p is momentum).

The real weighted probability has other factors, but they enter only as overall normalization factor and we worry about normalization only after the events have been produced.

For reference I have attached two plots. Normal HSN flux, and HSN flux weighted by the decay probability (which is the one fed to the HSN generator).

Normal HSN flux
HSN flux

HSN flux scaled by decay probability
HSN flux scaled by decay probability