Hi Chi,
Thanks for the message. Is your conclusion (electron right problematic)
consistent with Genya and Vitaly? I think your statement about the cross
section is very relevant. As we know, to form reliable asymmetries the
rates should be statistical. Is the spin sorting for left and right
detectors common or separate?
Richard
On Mon, 15 Mar 2004, Chi Zhang wrote:
>
> I would like to confirm that I see big polarization, 40%-60% depending on
> which runs I analyze with electrons into left sector. (perpendicular
> kinematics, asymmetry positive). while very small (~10%)
> tensor pol for electrons into the right sector(parallel kinematics,
> asymmetry negative).
>
> unfortunately, the parallel kinematics asymmetry should be the larger than
> the other one.
>
> I want to draw attention to the fact that I have never been able to
> reconstruct a ed-elastic cross section that is close to monte carlo for
> electron into right sector case!!
>
> I have much better agreement in cross section for the other(high
> polarization) case. So I would like to suggest the problem lies in
> detector/reconstruction.
>
> There have been a few periods, with right 2nd level trigger unplugged,
> right lads/nc turned on and off, starting from run 5502, we used a new
> trigger to beat down dead time, before that some beam tunning. I broke
> dowm runs by period but it does not seem to affect the results.
>
> I attached two plots on results for the latest runs. please see the right
> bottum figure in newest1.ps for cross section. as ussual, red mean
> electron into the right and blue means electrons into the left.
>
> newest2.ps is for asymmetry. The bottum right plot is a fit to
> (A_right - A_left) = pol*F. where F is fitted from monte carlo.
>
> PS. My analysis handles the vector Asymmetry by ignoring it and wish
> that in the end of the day it is small and cancel out.
>
> Chi
> On Mon, 15 Mar 2004, Richard Milner wrote:
>
> >
> > I am following the tensor polarization discussion on email. I think Genya
> > and Vitaliy should first resolve what they see. I understand that Genya
> > is using elastic scattering and Vitaliy (e,e'p). Is that right?
> >
> > Although I suggested reversing the transverse field, I think going
> > to purely longitudinal field probably will help resolve this quicker.
> >
> > Richard
> >
> >
> > On Mon, 15 Mar 2004, John Calarco wrote:
> >
> > >
> > > Genya
> > >
> > > I agree that we should follow either your suggestion to turn off the
> > > transverse holding field or Richard's suggestion to reverse it (I see
> > > them as being equivalent) as soon as is practical. Your comment that
> > > the elastic vector is small compared to the tensor asymmetry is correct,
> > > and therefore it should have a small effect. My worry is that somehow
> > > the data are being sorted incorrectly (some bit incorrectly set) and
> > > that the asymmetry is being "calculated" incorrectly from the data.
> > >
> > > John
> > >
> > >
> > > On Mon, 15 Mar 2004, Genya wrote:
> > >
> > > >
> > > >
> > > > Genya wrote:
> > > >
> > > > >
> > > > >
> > > > > vitaliy ziskin wrote:
> > > > >
> > > > >> Richard,
> > > > >> Which side gives 20%? This maybe a strange coincidence but the
> > > > >> tensor asymmetry for d(e,e'p)n also shows 20+/-12 % target
> > > > >> polarization in electron-left sector and 65 +/- 10% in electron-right
> > > > >> sector. To me this seems too strange of a coincidence, espacialy
> > > > >> considering that vector (e,e'p)n results are consistent in both
> > > > >> sectors. I, however, do not see how a target field can effect only
> > > > >> tensor asymmetry and not
> > > > >
> > > > >
> > > > > Actually, I see high polarization when electron goes to the right.
> > > > > Genya
> > > >
> > > > Soryy, I meesed this one up. In reality I see high polarization
> > > > with electron in LEFT sector, which confirms
> > > > Vitalij's observation.
> > > > Rickardo repeated my calculations of the "theoretical" asymmetry
> > > > and confirmed my results. Now matters
> > > > really look somewhat troubling. Perhaps we should switch to a
> > > > longitudinal only field to evaluate the situation.
> > > > And perhaps we should do it ASAP, may be tomorrow.
> > > > Genya
> > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> > --
> >
> >
> >
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