[Clascomment] OPT-IN:Target and Beam-Target Spin Asymmetries in exclusive Ï+ and Ïâ electroproduction with 1.6 to 5.7 GeV elec trons

[bosted at jlab.org]

Aloha Igor,
   Regarding:
  7) As far as I suggested, it is good to add SAID predictions
   I already have SAID07 and dropped it because it is off
by more than a factor of 10 in spin-averaged cross section
at high W and Q2, so I decided no point comparing to
asymmetries.
   Are you referring to a new SAID fit that is better
in terms of spin averaged cross section?
   At this point in time, 16 years after the experiment,
I simply don't have any more time to learn a new code,
however. It took me almost two weeks to learn the JANR
code and getting it to run on 64-bit machines and fixing
some bugs. Learning a new SAID code would probably take
many days, at the minimum.  As you probably know, I'm only
working in physics 2 months a year, and have a big backlog
of analyses that need attention. No one else is working on
this paper. I hope you will agree that it is not required
to add more fits to previous world data to this paper. The
main point is to provide a big set of data points for
use in new, improved fits by your group and others.
   Yours, Peter


> -----
> Igor Strakovsky, SAID INS The George Washington University
> Tel: 571-553-8344,Skype: igors1945_2, Fax: 202-994-3001
> Cell: 703-728-5627, Emails: igor at gwu.edu, igor at jlab.org
>
> On Sun, Feb 28, 2016 at 3:24 PM, <bosted at jlab.org> wrote:
>
>> Dear Igor,
>> That is really impressive work.  I have several comments and suggestions
>> for your
>> consideration...
>>
>> 1) Abstract: You do not have en-->epi-p data.  You did not collect data
>> on
>> free but bound neutron.  One cannot possible to measure pionEPR on the
>> "neutron" target you have to take into account FSI corrections to
>> convert
>> ed-->epi-pp into en-->epi-p. There are no FSI calculations for pionEPR.
>> FSI for asymmetries could be small but
>> still unknown. CHANGED to "...kinematic bins
>> for $\pi^+$ and 35,000 bins for $\pi^-$ production."
>>
>> 2) Abstract: Most of "previous world data" are CLAS measurements
>> (according to the SAID database - CLAS collected about 85% of the world
>> database) and I would  punch this fact. NOT DONE (doesn't seem
>> appropriate
>> to me).
>>
>> 3) Abstract: I do not think that last phrase is necessary here.  No
>> resonance couplings are presenting in the manuscript. CHANGED to
>> "When combined with cross section measurements,
>> the present results will provide powerful constraints
>> on nucleon resonance amplitudes at moderate and large
>> values of $Q^2$, for resonances with masses as high as 2.3 GeV."
>>
>> 4) line 16: your list of pi- measurements is uncompleted, check the SAID
>> database which has all available data. I cannot seem to get there: when
>> I
>> click on "data Base" on
>> http://gwdac.phys.gwu.edu/analysis/epr_analysis.html
>> nothing happens. Can you send any pi- reference you consider essentail.
>> Meanwhile, I've change to say "references include..."
>>
>> 5) line 45: I am not sure that one can possible to prove that your
>> treatment for en-->epi-p is good enough.  We published several PRC
>> papers
>> for pionPR analyses which allows to get gn-->pi-p from CLAS (g10) and
>> MAMI-B gd-->pi-pp measurements. inSpire can give you appropriate refs.
>> ANSWER: Text has been changed to be very
>> careful to say that we present measured asymmetries on deuteron target.
>> No
>> neutron response functions are extracted in this paper.
>>
>> 6) line 143: How is about a neutron-detection efficiency?  How your took
>> it into account? ANSWER: There is no need to account for any
>> efficiencies
>> in asymmetry measurements (the efficiency cancels in the ratio)
>>
>> Let me suggest to add more curves to your data-plots using EBAC and SAID
>> predictions which will obviously benefit this manuscript.
>> ANSWER: The JANR fit is from the EBAC group (Inna). I tried using SAID
>> but
>> ran into difficulties, and decided two curves were enough to illustrate
>> the point that new fits are needed now that we have more data.
>>
>> BTW I am not sure if I am familiar with JANR treatment but MAID07 does
>> not
>> fit available g*n-->pi-p data (they used some relationships between p
>> and
>> n targets) ANSWER: Inna (JANR) did not consider pi- production. She only
>> does
>> pi+ and pi0.
>>
>>
>>
>>
>>
>>
>>
>>
>