[clas12_rgk] trigger efficiency vs ECal treshold

[Francois-Xavier Girod]

Thank you Rafo, this is really helpful
I remember we did have a separate validation of the DC roads. Do you have
this documented? I think this included both simulations and data, but I
don't remember the momentum range. I think the DC roads can validated at
low momentum even with a 300 MeV threshold.

On Wed, Dec 12, 2018 at 7:30 PM Rafayel Paremuzyan <rafopar at jlab.org> wrote:

> Dear Fx, all,
>
> I looked back one of old presentations, and see that with 2.2 GeV run that
> we have in Jan 2018, the ESum threshold was 150 MeV
>
> https://docs.google.com/presentation/d/1OZ_BDsYiH6t8Mo_D_o9QPIoSQLKkvs7ckKwGx_u9vOs/edit?usp=sharing
> Please look into slide 11, the sharp fall of the trigger is below P < 1
> GeV.
>
> This is not exactly the same this trigger, but difference is minor, i.e.
> DC segments are added, then dc roads, and
> because of it some time constants were shifted. This gives good confidence
> that the current trigger is also efficient (99%+) above 1 GeV,
> however, if you would like exactly this trigger to be validated 1ith ESum
> > 150 MeV, we can take another random run (about 2 hours g/ good beam),
> and check it.
>
> Rafo
>
>
> On 12/12/18 7:05 PM, Viktor Mokeev wrote:
>
> Thank you FX for the comment!
>
>
> Extension of W-coverage may be also beneficial increasing chances to
> explore the hybrid baryon spectrum.
>
>
>  Best  Regards,
>
>                                     Victor
>
>
> ------------------------------
> *From:* Francois-Xavier Girod <fxgirod at jlab.org> <fxgirod at jlab.org>
> *Sent:* Wednesday, December 12, 2018 7:00:36 PM
> *To:* Viktor Mokeev
> *Cc:* clas12 rgk; clas12 first exp; Rafayel Paremuzyan
> *Subject:* Re: [clas12_rgk] trigger efficiency vs ECal treshold
>
> Dear Viktor
>
> Thanks for the feedback. Although hybrid baryon is not interested in the
> high W region, lowering the trigger threshold for hybrid baryon would only
> impact the experiment in terms of luminosity. The lower W / larger momentum
> region would still be in the trigger, and hybrid baryon could benefit from
> cross-checking their cross-sections at different luminosity.
>
> Best regards
> FX
>
> On Wed, Dec 12, 2018 at 6:26 PM Viktor Mokeev <mokeev at jlab.org> wrote:
>
> Dear All,
>
>
>  From FX trigger efficiency plot, I see efficiency problems at the lab.
> energies of the scattered electron <2.0 GeV or for \nu value above 5.5 GeV
> for the electron beam energy 7.5 GeV. It corresponds to the following W
> ranges where we have the problem with trigger efficiency:
>
>
> Q^2=2.0 GeV^2 W>3.0 GeV
>
> Q^2=5.0 GeV^2 W>2.5 GeV
>
>
> For hybrid baryon search, we have no any problem with the trigger
> efficiency at Q^2<2.0 GeV^2 since the lightest hybrids are expected in the
> mass range <2.5 GeV.  Furthermore, the initial search for hybrid baryons
> will be carried out at Q^2<2.0 GeV^2.
>
>
>  Best Regards,
>
>                                  Victor
>
>
> ------------------------------
> *From:* Francois-Xavier Girod <fxgirod at jlab.org>
> *Sent:* Wednesday, December 12, 2018 6:09:53 PM
> *To:* Viktor Mokeev
> *Cc:* clas12 rgk; clas12 first exp; Rafayel Paremuzyan
> *Subject:* Re: [clas12_rgk] trigger efficiency vs ECal treshold
>
> Dear Viktor
>
> Rafo can confirmed as he produced the plot, my understanding is that the
> electron momentum is measured by the drift chambers
>
> Best regards
> FX
>
> On Wed, Dec 12, 2018 at 6:08 PM Viktor Mokeev <mokeev at jlab.org> wrote:
>
> Dear FX,
>
>
>  Just to make sure, whether P on your plots is the energy=momentum of the
> scattered electron?
>
>
> Best Regards,
>
>                                     Victor
> ------------------------------
> *From:* clas12_rgk <clas12_rgk-bounces at jlab.org> on behalf of
> Francois-Xavier Girod <fxgirod at jlab.org>
> *Sent:* Wednesday, December 12, 2018 5:58:01 PM
> *To:* clas12 rgk; clas12_first_exp at jlab.org
> *Cc:* Rafayel Paremuzyan
> *Subject:* [clas12_rgk] trigger efficiency vs ECal treshold
>
> Dear all
>
> During today's meeting I attempted to have a discussion on the trigger
> efficiency as function of ECal threshold. Contradicting statements were
> made during the meeting, so I want this discussion to be on record here.
>
> Please see the plot
>
> https://www.jlab.org/Hall-B/secure/clas12/rec_mon/P_Good_emWithEC_5786.png
>
> from Rafo's study of the trigger efficiency. He analyzed run 5786 which
> was taken with the random trigger.
>
> - in blue all "good electrons" with Nphe>2, E_PCal > 60 MeV, sampling
> fraction > 0.2 and fiducial cuts
>
> - in orange, the electrons satisfy in addition E_ECal > 300 MeV
>
> - in red, the events for which the orange set was missing the electron
> trigger bit
>
> The trigger efficiency is defined as (orange - red) / orange
>
>
> https://www.jlab.org/Hall-B/secure/clas12/rec_mon/Eff_All_Good_em_trg_threshold_5786.png
>
> The trigger efficiency below 2 GeV drops rapidly, and measuring a cross
> section in this region is challenging
>
> My question during the meeting was: do we already have data to show the
> trigger efficiency when the threshold is 150 MeV. My understanding is that
> we do not have this data and that to answer this question we need to take
> another random trigger run with the lower threshold.
>
> What I have in mind is the following: I agree that the bulk of the RG-K
> data taking can take place at 300 MeV ECal trigger threshold and highest
> possible luminosity, but I would like to consider the possibility to take a
> few days at a lower trigger threshold to extend the cross section
> measurement  to higher W. Again my purpose is to minimize the final
> systematic uncertainties.
>
> Best regards
> FX
>
>
>
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