May I suggest not rushing into changing to long. target. Maybe, first
we need to understand what is going on. First of all, spin counting can
not be a suspect here because it is done the same way for both sectors
and for vector asymmetry. I agree with Chi, that we have a problem with
reconstruction rather than target or bit counting. What is our signal
to noise ration in both sectors? How well do we see elastic peak? How
well do we reconstruct momentum? I think that all these things need to
be addressed before we change setup.
Chi Zhang wrote:
>Hi Richard,
>
>My problem with electron into right sector is consistant with Genya's. But
>in constradict with Vitaliy's, which is better in LEFT electron. I don't
>know any details about Genya's analysis so I don't know to what extend he
>recovers the elastic cross section.
>
>I feel a little uneasy that analysis in ep elastic and other D2 channels.
>so I hope Genya had better cross section results.
>
>Just a follow up, please again see the attached dpe.ps. It draws (electron
>momentum reconstructed - electron momentum calculated from electron
>scattering angle). The sigma of the peaks are <=40MeV which is consistant
>with what we see with ep elastic. However, there is slight different in
>the position of the two peaks. on lower 30MeV than 0, one 20MeV higher.
>Tancredi pointed out to me that this is in fact a big left right
>inconsistancy, much bigger than the error in determination of the peak
>positions. again, red is electrons into the right.
>
>So it maybe is not a big suprise that we have inconsistant results in left
>and right sectors. Just it is our bad luck the poor results appear in the
>sector we expect to see the larger asymmetry.
>
>Chi
>
>On Mon, 15 Mar 2004, Richard Milner wrote:
>
>
>
>>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
>>
>>
>>
>
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