As a footnote, Feng translated POLRAD to C++, and his source codes can
be found in the BLAST CVS under 'userGen/epel/polrad'
--Chris
Haiyan Gao wrote:
>
> Hello Michael and others:
>
>
> My former student Feng Xiong did a lot of work implementing POLRAD
> into our 3He analysis for the JLab experiment. You may want to
> take a look
> at his thesis (Joanne Gregory should have copies) which might be useful.
>
> Haiyan
>
>
>
> On Tue, 9 Aug 2005, Michael Kohl wrote:
>
>> Agenda:
>> 1)Renee: news about hPz
>> 2)Pion production: Review of N-Delta analysis, inclusive p(e,e'), and
>> exclusive p(e,e'pi+), p(e,e'p)pi0, p(e,e'n)pi+. Runlist, event
>> selection, yields vs W,Q2,thcms;time and experimental asymmetries.
>> Status of MC: MAID + ep elastic, radiative effects (YX,AS,TF)
>> 3)On the meeting structure
>>
>>
>> Attending RF,DH,KD,JC,PK,VZ,CG,YX,CZ,AS,MS,MK.
>>
>> 1) Renee's update on hPz extraction for 2005
>> R. verified (and demonstrated!) that the used cuts are valid for the 2005
>> data. Fitting hPz at lowest 0.1<Q2<0.2 for pm<0.15 yields left-right
>> consistent result around 0.47. Still, hPz exhibits Q2 dependence. If
>> attributed to a deviation of the proton form factors from the
>> dipole, question is how much the form factor ratio should be changed
>> in MC
>> in order to agree with the measured asymmetries.
>>
>> 2) Yuan showed us again the event selection for (e,e'pi+)n, (e,e'n)pi+
>> and
>> (e,e'p)pi0 and corresponding asymmetries. There is a discrepancy between
>> MAID-MC based on DGen and MAID-MC from Aki which agrees better with
>> the data. Aki suspects a phi->phi+180-type error in DGen which may cause
>> sign changes of one or more response functions. YX is working on MAID
>> implementation.
>> On the validity of MAID in BlastLib, there should be references available
>> by Shalev Gilad (Hall C experiment) and also from A. Bernstein or Sean
>> Stave
>> to compare with. The MAID version in DGen evaluates pion production cross
>> sections from first principles, so there is in principle the danger that
>> it disagrees with what the website would predict. Sean earlier created
>> big
>> tables with MAID results covering the phase space of his experiment at
>> Mainz. We should have something similar for BLAST and interpolate
>> (like we
>> do with Arenhoevel's electrodisintegration). This is faster and more
>> reliable, I guess. I will meet Lothar Tiator in September.
>> Tavi is working on implementing POLRAD into generator. POLRAD, originally
>> for DIS, accounts for polarization-dependent radiative effects, also of
>> the produced pions. It needs MAID cross sections (or transition form
>> factors) for input. Effect on asymmetries can be large, as much as 40%
>> (!)
>> compared to the very small effects in elastic scattering (~1%).
>>
>> 3) It was raised wether and if so, how the structure of the analysis
>> meeting should be changed in order to be attractive and useful.
>> -The analysis meeting shall provide a forum for discussion and scientific
>> discourse
>> -The analysis meeting differs from the three-monthly collaboration
>> meeting in the sense that the latter is pure collection of results
>> without discourse while the former has focus on discussion, too. The
>> analysis meeting prepares for the collaboration meetings.
>> -The BLAST experiment is more than the sum of its proposals. The meeting
>> shall locate and make available synergistic effects. One's result can be
>> very useful for another one's analysis. Examples are manifold like hPz,
>> Pzz, spin angle, kinematic corrections, etc. etc.
>> -The meeting offers practise for the student in presentations
>> -It is feedback to everyone's analysis - one should not only notice at
>> the
>> time of a collaboration meeting if one is on a wrong track
>> -We shall have topical meetings, once per week
>> -The agenda of the next meeting should be determined at the end of each
>> meeting.
>> -People should come prepared, especially when they are supposed to
>> report.
>> This means a few slides are in order to make things easier to understand.
>> HOWEVER, presentations at the analysis meeting are no conference talks
>> and are thus far more informal. Also recycled slides from earlier
>> meetings may be useful for this. Renee's presentation of her progress was
>> a very nice example on how it could be.
>> -It was pointed out that the minutes could be rotated, but for the time
>> being I'm fine with doing it.
>> -I will try to keep the length of the meeting below 90 minutes.
>>
>>
>>
>> Proposed agenda for meeting on Wednesday 2005/08/17:
>> -Radiative effects in the BLASTMC generator (Mascarad)
>>
>>
>> Regards,
>>
>> Michael
>>
>>
>>
>
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