Cross-check meaning and/or filling of `rec.nd.lar.dlp.showers.direction.[i]`

[alexbooth92]

At the ND sim / reco + LBL Jan 2026 Workshop, Eva noted strange features in the distribution of this variable.

[sabater13]

Here is the angle between the beam direction and the shower direction, i.e. rec.nd.lar.showers.direction.[i]

[sabater13]

The peak at 90 degrees in corresponds to low energy and tiny shower fragments (similar explanation for the peak at 130-140 degrees).

[sabater13]

From the previous plot, it is clear that the peak at 90 degrees corresponds to low energy shower fragments. One can apply a cut that removes showers with energies lower than 0.015 GeV. This removes most of the low energy shower fragments that lie in the 90 degrees peak.