Regarding Minimum Momentum Cut on Tracking

[Simple-Shyam]

Dear Experts,

I am using ACTs but I want to understand how much is the minimum momentum threshold (energy loss is significant) allowed for the track fitting? How is the result at the low momentum range where energy loss is significant?

There is also a question on the track finding and fitting, I was reading in a paper we find the seed using conformal mapping (3-hits) then we use Combinatorial Kalman filter to fit the track. What if we have only three hits to fit the track? Do we still use the Combinatorial Kalman filter with only three hits.

Suppose if we have two hits, I checked that the track can not be fitted using a track fitting package as it gives momentum uncertainties are very high or we have a cut off on hits that 2 hits can't be processed for track fitting.
How ACTS handles the situation when we have only two hits?

Thank You in Advance
Shyam