[clas12_rgk] [Clas12_first_exp] trigger efficiency vs ECal treshold

Wed Dec 12 19:42:31 EST 2018

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 <mailto: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 <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> <mailto: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 <mailto: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 <mailto: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 <mailto: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 <mailto:clas12_rgk-bounces at jlab.org>> on behalf of Francois-Xavier Girod <fxgirod at jlab.org <mailto:fxgirod at jlab.org>>
>> Sent: Wednesday, December 12, 2018 5:58:01 PM
>> To: clas12 rgk; clas12_first_exp at jlab.org <mailto: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 <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 <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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