Re: [BLAST_SHIFTS] tensor polarization results

From: Chi Zhang (zhangchi@MIT.EDU)
Date: Mon Mar 15 2004 - 15:59:01 EST


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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