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

[Robert Johnson]

Only the default values are hardcoded. They all can be, and may be,
modified by the steering file.

Robert P. Johnson
Professor
Physics Department
Santa Cruz Institute for Particle Physics
University of California at Santa Cruz
Santa Cruz, CA 95064
831-459-2125
rjohnson at ucsc.edu


On Tue, Jun 7, 2022 at 5:16 PM Bravo, Cameron B. <bravo at slac.stanford.edu>
wrote:

>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_JeffersonLab_hps-2Djava_blob_master_tracking_src_main_java_org_hps_recon_tracking_kalman_KalmanParams.java&d=DwIFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=JaSEOiNc_6InrJmbYDvKU2tZqhhONpIkbyl_AUnkDSY&m=eeujiFVKSjADMgqS1ClxeunyW5A5sPhPmCmYbDbICELGspekcXlKphxMj_UxIDyS&s=xyGU-hg7vjN8ya3i631smGdU8__pcKj_O59GPR8OldI&e= 
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_JeffersonLab_hps-2Djava_blob_master_tracking_src_main_java_org_hps_recon_tracking_kalman_KalmanParams.java&d=DwMF-g&c=CJqEzB1piLOyyvZjb8YUQw&r=JaSEOiNc_6InrJmbYDvKU2tZqhhONpIkbyl_AUnkDSY&m=_dIpefaElthIovRGpd51k2QSLzXqneNsG1eYNUkorr_FLz5DlskHP2uNzXUvQw3q&s=lW22qIYz7qremO_4SZDK0LwuvDyYZ55EzFOpyQI2pz0&e=>
>
>
> Probably comes from one of these hardcoded numbers.
> ------------------------------
> *From:* Hps-analysis <hps-analysis-bounces at jlab.org> on behalf of Bravo,
> Cameron B. <bravo at slac.stanford.edu>
> *Sent:* Tuesday, June 7, 2022 5:10 PM
> *To:* Graf, Norman A. <ngraf at slac.stanford.edu>; Graham, Mathew Thomas <
> mgraham at slac.stanford.edu>; hps-analysis at jlab.org <hps-analysis at jlab.org>
> *Subject:* [Hps-analysis] [EXTERNAL] Re: Track Chisq Cuts
>
> It is what I said. If I require exactly 14 hits I do see a ~cut at 25, but
> also do see a few events sprinkled above 25 like you do.
> ------------------------------
> *From:* Graf, Norman A. <ngraf at slac.stanford.edu>
> *Sent:* Tuesday, June 7, 2022 5:03 PM
> *To:* Bravo, Cameron B. <bravo at slac.stanford.edu>; Graham, Mathew Thomas <
> mgraham at slac.stanford.edu>; hps-analysis at jlab.org <hps-analysis at jlab.org>
> *Subject:* RE: Track Chisq Cuts
>
>
> Hi Cameron,
>
>
>
> Thanks for that feedback. Are these top tracks with 14 hits?
>
>
>
> Norman
>
>
>
> *From:* Bravo, Cameron B. <bravo at slac.stanford.edu>
> *Sent:* Tuesday, June 7, 2022 4:39 PM
> *To:* Graf, Norman A. <ngraf at slac.stanford.edu>; Graham, Mathew Thomas <
> mgraham at slac.stanford.edu>; hps-analysis at jlab.org
> *Subject:* Re: Track Chisq Cuts
>
>
>
> 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.
>
>
>
> 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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