[Hybrid baryons] [clas12_rgk] [EXTERNAL] Reminder: RGK meeting tomorrow at 8:00 Jlab

[Francois-Xavier Girod]

Dear Valery

> I think that we don't need to apply the cut on the opening angle between
two photons. It is almost the same as to cut gg inv. mass. The inv mass
spectrum will be fine even without top cut I believe.

One can see the difference between slide 27 and 36: the cut on opening
angle only removes problematic events at low IM and does not cut any of the
signal
It is a safe cut and sets a value for the minimum distance between clusters
which is something that is good to know
That being said, for the simulations there is no problem to fit the IM
spectrum without this cut and one can choose not to use it

However I am not certain things are as clean in the data. I use this cut
for data analysis personally. All the cuts shown in my slides should be
adjusted by Anna for her data analysis.

Best regards
FX

On Mon, Apr 27, 2020 at 4:18 PM Valery Kubarovsky <vpk at jlab.org> wrote:

> Dear FX,
>
> Very good study!
>
> I remember that we applied very efficient cut to remove radiative photons
> as well as background coming from the fluctuation of the electron shower in
> the calorimeter. We just did not consider the photons in the same sector as
> electron.
> It worked  for eta selection and will work even better for the pi0.
>
> I think that we don't need to apply the cut on the opening angle between
> two photons. It is almost the same as to cut gg inv. mass. The inv mass
> spectrum will be fine even without top cut I believe.
>
> Best regards,
> valery
>
>
> ------------------------------
> *From:* clas12_rgk <clas12_rgk-bounces at jlab.org> on behalf of
> Francois-Xavier Girod <fxgirod at jlab.org>
> *Sent:* Sunday, April 26, 2020 17:06
> *To:* clas12_rgk at jlab.org <clas12_rgk at jlab.org>; hybrid baryons <
> hybrid_baryons at jlab.org>
> *Subject:* Re: [clas12_rgk] [EXTERNAL] Reminder: RGK meeting tomorrow at
> 8:00 Jlab
>
> Dear all
>
> As a follow up from Friday's meeting, Anna agreed to provide me with her
> eppi0 simulation files so I can take a look with my code
>
> I posted some slides summarizing my findings on the docDB page here
> https://clas12-docdb.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=637
>
> I think that most of the background Anna observed comes from photons
> generated by the electron bremsstrahlung
> One can mostly remove all this background with a simple cut on the angle
> between electron and photon > 7 degrees
> The generated kinematics indicates that such a cut should be fine
>
> In addition I applied a set of exclusivity cuts similar to what I used for
> the deep pi0 selection
> Note that the values of these cuts should be adjusted for the analysis of
> the data, but overall I expect they would help clean up the backgrounds
> from other reactions as well
>
> In general it seems prudent to remove photons around the electron
> direction, unless one is directly interested in bremsstrahlung events
>
> Best regards
> FX
>
>
> On Thu, Apr 23, 2020 at 7:52 PM Annalisa D'Angelo <
> annalisa.dangelo at roma2.infn.it> wrote:
>
> Dear All,
>
> this is a reminder of tomorrow RGK meeting at 8:00 am Jlab time.
>
> The bluejeans link is:
>
> https://jlab.bluejeans.com/214576976
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab.bluejeans.com_214576976&d=DwMFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=t2OnxVoP8YJyzuxpHKwj1tmrMj6s1mZ4pgV16sZJZb8&m=Xv8He5Zu2WrGWdLaLCq_bbPgPtJyiHCbvGjBnZJp-3w&s=D1duBcnVCXxtVPUS7bfmvQQ1grPEM014tffjotoLbFw&e=>
>
>
> All the best
>
> Volker and Annalisa
>
> --
> ================================================
> Prof. Annalisa D'Angelo
> Dip. Fisica, Universita' di Roma "Tor Vergata"
> Istituto Nazionale di Fisica Nucleare
> Sezione di Roma Tor Vergata, Rome Italyemail:annalisa.dangelo at roma2.infn.it
> Jefferson Laboratory, Newport News, VA USA
> Email: annalisa at jlab.org
> Tel: + 39 06 72594562
>
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>
>
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