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

[Igor Strakovsky]

Dear Peter,

I understand your position and limited time factor.  I do not ask you you
to learn SAID code (I offered
you to generate SAID output by myself if you can give me your condition)
but we fitted all available
900 g*n-->pi-p data and it is very natural that our predictable power is
very low.  As far as you probably
know, our fit is data driven and model independent.  The unclear factor of
your new measurements
is that FSI is unknown.

But that is your paper and all is up to you
Cheers, Igor

-----
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 Wed, Mar 2, 2016 at 12:36 PM, <bosted at jlab.org> wrote:

> 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.
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
>
>
>
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