Support combining downstream tracks in ThOr::Combiner<T>
The new ThOr::Combiner<T>
uses a templated and vectorised version of ParticleVertexFitter
. The templated version does not currently support input downstream tracks (without VELO segments); this logic needs to be imported from the original version.
As a first step, support for combining downstream tracks could be introduced by converting to legacy LHCb::Track
objects and using the Run1-2 tools for extrapolating tracks to their position of closest approach. This is likely to not be very performant, but the number of distinct use-cases for combining downstream tracks is relatively small (K_{\text{S}}^0
, \Lambda^0
, hyperons... of course those use cases are very important) so this may be an acceptable solution for a while.
This depends on LHCb#97 (closed), which should provide an SOA input data structure that can hold fitted downstream tracks.