[Halld-physics] Physics Working Group Meeting: Tuesday, October 16 @ 11:15 am

[Igor Strakovsky]

Hi Justin,

According to my understanding there are two different run periods

- this fall which will allow to cover 4-9 GeV or so.  CLAS6 does not have
pol measurements

- next summer which is a low energy run which you spelled out. that is
different story

Cheers, igor


On Wed, Oct 17, 2018 at 1:15 PM Justin Stevens <jrsteven at jlab.org> wrote:

> Hi Igor,
>
> Thanks for your feedback.  My understanding is the accelerator would run
> at half energy (Ee ~ 5.5 GeV), and as usual we could choose to set the
> coherent peak as we prefer.  The hodoscope in this case would cover Eg ~
> 1.5 GeV to the endpoint, although it will still be only half instrumented
> (sampling) between 1.5 and 3.5 GeV.  So data below Eg = 4 GeV could be
> possible in this scenario, but at a lower efficiency.
>
> -Justin
>
> On Oct 15, 2018, at 3:11 PM, Igor Strakovsky <igor at gwu.edu> wrote:
>
> Hi Justin,
>
> It would be good to spell out a possible Eg range and our goals for summer
> of 2019.  Then all depends.
>
> I reported twice that if our range is limited by 4 - 6 GeV and our main
> goal is diff cross sections then
> g12 from CLAS6 will work for us.  There are no CLAS pol measurements in
> this case.  So, we have
> gp-->pi0p cross sections published several month ago and Volker's analyses
> for gp-->etap and
> gp-->omegap are under the HW group review now.
>
> If one can possible to go below 3 GeV then we will have more options
> including polarized
> measurements. Additional benefit will come from the ability to use the PWA
> technology to evaluate
> new data and possibility to provide "good" event generators for MC.  See
> my slides at DB
>
> Cheers, igor
>
>
>
> -----
> Igor Strakovsky, SAID INS The George Washington University
> Tel: 571-553-8344(VC),202-994-4742(FB),Skype: igors1945_2,
> Cell: 703-728-5627,Emails: igor at gwu.edu, igor at jlab.org
>
>
> On Mon, Oct 15, 2018 at 12:50 PM Justin Stevens <jrsteven at jlab.org> wrote:
>
>> Hi All,
>>
>> There’s been a proposal to have a short discussion about a potential
>> low-energy run in Summer 2019 during tomorrow’s physics meeting.  To frame
>> the discussion: the accelerator plans to run at ~half energy during
>> June/July 2018 and GlueX could potentially run parasitically during this
>> period.
>>
>> We had some discussion about the potential usefulness of low-energy
>> running earlier this year (comparison to cross section measurements from
>> CLAS, energy-dependence of polarization observables, etc.), but that was in
>> a different context of using the full energy electron beam with lower
>> coherent peak settings (see
>> https://halldweb.jlab.org/wiki-private/index.php/Aug_7,_2018,_Physics_Working_Group
>> ).
>>
>> If you have something you would like to contribute to the discussion,
>> please let me know.
>>
>> -Justin
>>
>> On Oct 14, 2018, at 1:46 PM, Justin Stevens <jrsteven at jlab.org> wrote:
>>
>> Hi All,
>>
>> Our next Physics WG meeting we be Tuesday, October 16 at 11:15 am,
>> https://halldweb.jlab.org/wiki-private/index.php/Oct_16,_2018,_Physics_Working_Group.
>> Please let me know if you have something you would like to present.
>>
>> -Justin
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