This MR adds a new VSI configuration called VSI_Muons to the LLP1 derivation. This VSI configuration is optimised for the reconstruction of muons with large displacement, but small d0-values, typical for boosted long-lived particle signatures. This is developed in the context of the low-mass dimuon analysis ANA-EXOT-2024-18 and might also be interesting for other analyses in the LUP group.
There are currently three VSI containers in the LLP1 derivation; VSI, VSI_Leptons and VSI_LepTrack. All of these require a minimum d0 value at either 1 mm or 2 mm for at least one track in each two-track seed vertex. In addition, the track selection vetoes tracks associated to the PV. The new VSI_Muons configuration is a copy of the VSI_Leptons configuration with the following modifications:
Removed veto against tracks from PV
Removed minimum d0 requirement
Added requirement on the minimum distance between each two-track seed vertex and the PV to be >0.5 mm
Removed electron tracks from the track selection, thus keeping only muon tracks
The last two changes serve to reduce the increase in DVs coming from the first two changes.
The increase in CPU and disk usage for the DAOD_LLP1 is negligible.
