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

Elton Smith elton at jlab.org
Tue Oct 23 10:06:08 EDT 2018


Hi Justin,
For reference below are some CLAS references on 2pi production and rho 
and omega-meson production at large momentum transfer.  Cheers, Elton.



@article{PhysRevD.80.072005,
   title = {Photoproduction of 
${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ meson pairs 
on the proton},
   author = {Battaglieri, M. and others},
   collaboration = {CLAS Collaboration},
   journal = {Phys. Rev. D},
   volume = {80},
   issue = {7},
   pages = {072005},
   numpages = {19},
   year = {2009},
   month = {Oct},
   publisher = {American Physical Society},
   doi = {10.1103/PhysRevD.80.072005},
   url = {https://link.aps.org/doi/10.1103/PhysRevD.80.072005}
}

@article{PhysRevLett.90.022002,
   title = {Photoproduction of the $\ensuremath{\omega}$ Meson on the 
Proton at Large Momentum Transfer},
   author = {Battaglieri, M. and others},
   collaboration = {CLAS Collaboration},
   journal = {Phys. Rev. Lett.},
   volume = {90},
   issue = {2},
   pages = {022002},
   numpages = {5},
   year = {2003},
   month = {Jan},
   publisher = {American Physical Society},
   doi = {10.1103/PhysRevLett.90.022002},
   url = {https://link.aps.org/doi/10.1103/PhysRevLett.90.022002}
}




@article{PhysRevLett.87.172002,
   title = {Photoproduction of the ${\ensuremath{\rho}}^{0}$ Meson on 
the Proton at Large Momentum Transfer},
   author = {Battaglieri, M. and others},
   collaboration = {CLAS Collaboration},
   journal = {Phys. Rev. Lett.},
   volume = {87},
   issue = {17},
   pages = {172002},
   numpages = {5},
   year = {2001},
   month = {Oct},
   publisher = {American Physical Society},
   doi = {10.1103/PhysRevLett.87.172002},
   url = {https://link.aps.org/doi/10.1103/PhysRevLett.87.172002}
}




Elton Smith
Jefferson Lab MS 12H3
12000 Jefferson Ave STE 4
Newport News, VA 23606
(757)269-7625
(757)269-6331 fax

On 10/23/18 9:36 AM, Igor Strakovsky wrote:
> Cool. Then, please adjust this plan accordingly.  I can provide CLAS 
> g1c ds/dO as I did for
> g12.  Please let me know
>
> 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 <mailto:igor at gwu.edu>, 
> igor at jlab.org <mailto:igor at jlab.org>
>
>
> On Tue, Oct 23, 2018 at 9:27 AM Justin Stevens <jrsteven at jlab.org 
> <mailto:jrsteven at jlab.org>> wrote:
>
>     The minimum Eg is 25% of the endpoint energy, which is fixed by
>     the tagger field and TAGH counter geometry.  So the minimum Eg for
>     these runs would be ~2.9 GeV.
>     -Justin
>
>>     On Oct 23, 2018, at 9:22 AM, Igor Strakovsky <igor at gwu.edu
>>     <mailto:igor at gwu.edu>> wrote:
>>
>>     Hi Justin,
>>
>>     Plan looks great.  I have two small comments
>>
>>     - The min Eg is still unclear.  So, if one can possible to go a
>>     little bit below 3 GeV then CLAS
>>     g1c data for pi0 is reachable [DUGGER, PRC76, 025211(2007)]: Eg
>>     = 2875, 2825, 2775 and so on
>>
>>     - I would not use previous measuremen
>>     <https://halldweb.jlab.org/DocDB/0008/000809/002/GlueX_doc_809.pdf>as the
>>     source to compare with because most of data
>>     came from brem Bonn measurements which systematics is out the
>>     control.
>>
>>     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 <mailto:igor at gwu.edu>,
>>     igor at jlab.org <mailto:igor at jlab.org>
>>
>>
>>     On Tue, Oct 23, 2018 at 7:54 AM Justin Stevens <jrsteven at jlab.org
>>     <mailto:jrsteven at jlab.org>> wrote:
>>
>>         Hi Igor, All,
>>
>>         Yes, as we discussed at the Physics WG meeting last week,
>>         there are 2 possibilities for low energy measurements which
>>         correspond to your bullets below.  The priority was given to
>>         proposing a run plan for this Fall, since time is limited. 
>>         Thanks to Sean for collecting the relevant data and rate
>>         estimates for this Fall’s proposal at
>>         https://halldweb.jlab.org/wiki-private/index.php/2018_Low_energy_measurements.
>>         The short summary is that we would like to propose a ~5 day
>>         run with a lower PS field setting to give statistical errors
>>         <10% on cross sections for comparison to previous
>>         measurements, and this is on the agenda for today’s bi-weekly
>>         meeting.
>>
>>         This Fall’s proposal of course does not preclude running in
>>         Summer 2019, but would give us some data in the short term to
>>         compare with previously measured cross sections.  To make a
>>         decision on Summer 2019 running, we would need a similar
>>         proposal with the stated goals, rate estimates, and required
>>         running time.
>>
>>         -Justin
>>
>>>         On Oct 17, 2018, at 4:34 PM, Igor Strakovsky <igor at gwu.edu
>>>         <mailto:igor at gwu.edu>> wrote:
>>>
>>>         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 <mailto: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 <mailto: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
>>>>             <mailto:igor at gwu.edu>, igor at jlab.org <mailto:igor at jlab.org>
>>>>
>>>>
>>>>             On Mon, Oct 15, 2018 at 12:50 PM Justin Stevens
>>>>             <jrsteven at jlab.org <mailto: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 <mailto: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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>>>>>                 Halld-physics at jlab.org <mailto:Halld-physics at jlab.org>
>>>>>                 https://mailman.jlab.org/mailman/listinfo/halld-physics
>>>>
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>>>>
>>>
>>
>
>
>
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