[Frost] target polarization

[Michael Dugger]

Hi,

Is there a general agreement within FROST that we use the helicity 
assignments given at the bottom of the Helicity assignment web page at
http://clasweb.jlab.org/rungroups/g9/wiki/index.php/Helicity_assignment_for_g9a
?

Is anyone using helicity assignments different than those given by 
Steffen?

I think we should be clear as to what values everyone should use.

Thanks for your time.

Take care,
Michael

On Thu, 27 Jan 2011, Steffen Strauch wrote:

> Dear Michael,
>
> The statistics of the pi+N data is good enough to look at the asymmetries run-by-run.  That all runs give consistent results of the experimental asymmetry despite different target polarizations, target field settings, and half-wave plate configurations, except for all runs with 1.645 GeV beam energy, hints in my opinion at a difference between the status of the helicity bit and the actual beam helicity in the hall for the two electron beam energies.
>
> I discussed this some time ago with Stepan and he mentioned that "it is not uncommon that definition of the helicity bit changes with changes in injector."  I was hoping the Moeller runs would allow to give a unique correlation between the helicity bit and the actual beam helicity.  Information about the g9a Moeller runs are posted at the bottom of the following page:
>
> http://clasweb.jlab.org/rungroups/g9/wiki/index.php/Beam_Polarization_%28Circ.%29
>
> I haven't followed up on that since though.
>
> All the best,
> Steffen
>
>
>
> On Jan 27, 2011, at 2:54 PM, Michael Dugger wrote:
>
>>
>> Hi,
>>
>> I would like to have a FROST approved list of target polarization
>> directions for g9a on a run by run basis.
>>
>> I have been looking at the "Helicity assignment for g9a" web page at
>> http://clasweb.jlab.org/rungroups/g9/wiki/index.php/Helicity_assignment_for_g9a
>> and see different results!
>>
>> Brian has told me that I might want to use Steffen's list, but I am
>> concerned about the comment:
>> "The asymmetry of the 1.645 GeV data has the opposite sign without an
>> additional sign change. This sign change needs still to be understood."
>>
>> We need one single FROST approved list. Does this list exist?
>>
>> Thanks for your time.
>>
>> -Michael
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>
>