[Primexd] fcal pi0 skim

[Colin Gleason]

That's right. Having r<20 definitely suppresses events in the inner layers.
I think this would extend up to the third layer in some cases. It actually
makes me wonder why we see any showers in blocks near the beam hole. Sean,
can you remove this cut and produce 10 or so pi0 skim files for a run? It
would be interesting to see what effect this has not only on the inner
blocks, but also on the file size. You could also require 1 of the photons
to come from r>20, and the other from anywhere.

On Sat, Nov 17, 2018 at 11:59 PM Ilia Larin <ilarin at jlab.org> wrote:

>
>  Hi Sean,
>
> I believe r>20cm (if it's the distance from the beamline)
> should completly reject the most inner layer.
> Also 500MeV cut looks too strong, espcially for uncalibrated case.
> I didn't rely on clustering at all while preselecting events.
>
> Regards,
>  Ilya
>
>
> ----- Original Message -----
> From: "Sean Dobbs" <sdobbs at fsu.edu>
> To: "Ilya Larin" <ilarin at jlab.org>
> Cc: "Colin Gleason" <gleasonc609 at gmail.com>, primexd at jlab.org
> Sent: Saturday, November 17, 2018 11:30:42 PM
> Subject: Re: [Primexd] fcal pi0 skim
>
> Hi all,
>
> I took another look at the current definitions of the FCAL pi0 skim.  They
> are:
>
> - Pair together two FCAL showers which are not matched to tracks (given
> some track quality criteria) with E > 500 MeV, and r > 20 cm
> - The difference between the shower times must be < 10 ns
> - M(gg) < 300 MeV
>
> I think the 20 cm radial cut would suppress the number of showers in the
> inner rings?
>
> In either case, it would be good to know if the inner ring pi0 showers
> Ilya is seeing satisfy these criteria, or which ones are not satisfied.
>
> Cheers,
> Sean
>
> On Sat, Nov 17, 2018 at 10:48 PM Ilia Larin <ilarin at jlab.org<mailto:
> ilarin at jlab.org>> wrote:
>
>  Hi Colin,
>
> I checked that skim file.
> I see nothing at all in the most inner FCAL layer,
> and highly suppressed statistics for 2nd and 3rd FCAL inner layers.
>
>  Ilya
>
> ----- Original Message -----
> From: "Colin Gleason" <gleasonc609 at gmail.com<mailto:gleasonc609 at gmail.com
> >>
> To: "Ilya Larin" <ilarin at jlab.org<mailto:ilarin at jlab.org>>
> Sent: Friday, November 16, 2018 5:22:10 PM
> Subject: fcal pi0 skim
>
> Ilya,
>
> Here is the location of the pi0 skim:
>
>
> /cache/halld/RunPeriod-2018-08/calib/ver01/FCAL_pi0/Run050930/hd_rawdata_050930_000.pi0fcalskim.evio
>
> We only skim over 10% of the run due to computation limits, so there should
> be around 30 files in the directory. I think 1 run should be enough to see
> and compare pi0s. Iff we need more, we can use up to 10 files. If you run
> with  -PNTHREADS=4, then it should take 1-2 minutes to run interactively.
> If you still see pi0s, then you can probably use these skims to save time.
> --
> Colin Gleason
> Postdoctoral Fellow
> Indiana University
> Department of Physics
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-- 
Colin Gleason
Postdoctoral Fellow
Indiana University
Department of Physics
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