[Hps-analysis] [EXTERNAL] Re: Track Chisq Cuts

[Bravo, Cameron B.]

Hello Norman,

I see plenty of KF tracks with chi2/ndf over 25 in run 14166. This is all KF tracks in the top in partition 37 of that run using a detector I made last week.
I did require chi2/ndf be less than 1000 for this plot.
[cid:b92c5b65-bce6-4a59-a767-f2e2885e47d5]

Cheers,
Cameron
________________________________
From: Hps-analysis <hps-analysis-bounces at jlab.org> on behalf of Graf, Norman A. <ngraf at slac.stanford.edu>
Sent: Tuesday, June 7, 2022 3:59 PM
To: Graham, Mathew Thomas <mgraham at slac.stanford.edu>; hps-analysis at jlab.org <hps-analysis at jlab.org>
Subject: [Hps-analysis] [EXTERNAL] Track Chisq Cuts


Hello All,



Here is a followup to my presentation at today’s meeting with somewhat higher statistics. Recall that track1 is associated with a calorimeter cluster, whereas track2 has no such requirement. To get around the bimodal momentum distribution in top tracks I require 14 hits on tracks on the top and 13 hits on tracks on the bottom (due to the dead sensor). I plot here the chisq/ndf for Møller candidates with such tight restrictions on the number of hits. Not only is the track fit much worse for top tracks, there is a hard cutoff at 25, which is clearly cutting into the number of tracks on the top. I have not explicitly applied this cut in my analysis.



Looking at a more general sample of tracks, I notice a similar cutoff at higher values of chisq, although it varies by number of hits on the track. Before I dive into the code does this look familiar to anyone? Is there an explicit maximum chisq cut being applied in the current track reconstruction?



Thanks,

Norman
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