buggy nutau

[Alex Olivas]

it seems to me that in the nutau nugen dataset 6539 the light emission
from muons (if present in the event) is missing. I attach a scatter plot
of muon energy vs muon track length (LDir) in IceCube?. This should depend
only on the muon energy (and vertex position), but not on the primary
type. However, the reconstructed track length is aleays around 100m for
nu-tau primary. That value can be reached by the cascade at sufficiently
high energy.

It looks like there are two populations of muons in the tau MC, as I would
expect: one at very low muon energy (below 10 GeV) originating in the
cascade. The other component is at higher energies (>100 GeV) and is
originating in the 17% tau->muon decay channel. So the particle phyiscs
seems okay in that MC, but it was probably missed to simulate the light
from the muon. This makes dataset 6539 unusable. We need urgently a fixed
nutau dataset.

Cheers,

Andreas

This is likely due to the way nugen uses the propagators. For NuTau? it uses the tau
propagator and would not propagate muons in the final state.

[Alex Olivas]

This was caused by the propagator-as-service issue, where muons were not being propagated in tau samples.

[Alex Olivas]

Milestone IceSim? 3.2 deleted