[Clas12_first_exp] [clas12_rgk] trigger efficiency vs ECal treshold

Wed Dec 12 19:58:59 EST 2018

I believed we are using the DC roads
If we are not then my question is moot

On Wed, Dec 12, 2018 at 7:56 PM Stepan Stepanyan <stepanya at jlab.org> wrote:

> I am sure you can, but you should ask Andrea.
>
> Are we using roads or segment now.
>
> Stepan
>
> On Dec 12, 2018, at 7:46 PM, Francois-Xavier Girod <fxgirod at jlab.org>
> wrote:
>
> 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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>>
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