Hardcoded cut in Orthogonal seed finder #5286
Description
We are using the Acts Orthogonal seed finder in ePIC. We observe some seeding inefficiencies in the transition region from the barrel to the endcap for lower momentum particles. I think the issue is that a hardcoded cut is applied here: https://github.com/acts-project/acts/blob/v46.0.0/Core/include/Acts/Seeding/SeedFinderOrthogonal.ipp#L379.
As I understand the code, we have particles where valid bottom and top space point candidates are found around a middle space point (passing all doublet-level cuts including validTuple). However, when filterCandidates attempts to combine these into triplets, all combinations are rejected by the hardcoded |tanLM − tanMT| > 0.005 angular consistency cut. This cut is too tight for our endcap geometry, where non-uniform layer spacing in z causes the bottom–middle and middle–top slopes to differ by more than 0.005 rad even for genuine tracks.
Can this cut be replaced by a configurable parameter? Or perhaps the cut can be removed since a cut on deltaCotTheta2 is applied a few lines after?