[clas12_rgk] [Clas12_first_exp] trigger efficiency vs ECal treshold

Wed Dec 12 19:46:17 EST 2018

Dear Stepan

Yes, this is what I am asking for: can we please have the plot showing the
DC roads efficiency vs momentum?
I only need this material for discussion of my earlier proposal

Best regards
FX

On Wed, Dec 12, 2018 at 7:42 PM Stepan Stepanyan <stepanya at jlab.org> wrote:

> FX,
>
> Can you please clarify what you are exactly asking. The DC roads or
> segments in the trigger have nothing to do with trigger efficiency
> dependance on ECal trigger threshold. If you worry about efficiency of DC
> segments or roads for low momentum (~1 GeV) electrons or tracks, Andrea did
> that studies and as far I remember trigger had almost 100% efficiency.
>
> Stepan
>
>
> On Dec 12, 2018, at 7:35 PM, Francois-Xavier Girod <fxgirod at jlab.org>
> wrote:
>
> 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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