Re: ed rates Re: [BLAST_ANAWARE] vector polarization

From: Chi Zhang (zhangchi@MIT.EDU)
Date: Tue Jul 06 2004 - 16:13:08 EDT


My mistake. I don't know why I included 8390 and stuff. thanks

On Tue, 6 Jul 2004, vitaliy ziskin wrote:

> Chi,
> use runs starting with 8479. This is when we think the to problem was
> fixed. Also, use runs upto 8598.
>
> Cheers, Vitaliy
>
> Chi Zhang wrote:
>
> >Hi, all
> >
> >Unfortunately, from the ed events so far, I do not seem to see an increase
> >in rate AT ALL. rather, I have
> >deuteron in left 2633 in right 3205 total charge 16267 C
> >rate: 0.36 events/C which is lower than even the march 40cm runs. missing
> >counts in electron right still persists.
> >
> >I do hope someone could cross check the total charge I got. I used runs
> >betweem 8390 and 8578.
> >
> >Chi
> >
> >On Tue, 6 Jul 2004, Aaron Joseph Maschinot wrote:
> >
> >
> >
> >>there is about 17kC of polarized deuterium data since last thursday (there
> >>is a little more such data, but root yells about the lrn files not being
> >>closed correctly).
> >>
> >>this data gives me a QE ep rate of 9.5 events/C. this is UP about 60%
> >>compared to the corresponding rate before the most-recent shutdown.
> >>
> >>take a look at the attached plots of the bema-vector asymmetry versus
> >>missing momentum and Q2, respectively. all show a massive increase
> >>in vector polarization:
> >>
> >>
> >> dilution | vec pol (assuming h = 0.64+-0.01)
> >> (left) (right) | (left) (right)
> >> ------------------------------------------------------------------
> >>vs p_m : 0.657 +- 0.026 0.576 +-0.020 | 1.027 +- 0.044 0.900 +- 0.034
> >> |
> >>vs Q2 : 0.688 +- 0.027 0.611 +-0.021 | 1.075 +- 0.045 0.955 +- 0.036
> >>
> >>
> >>ummm... yeah. maybe this is a little too good. isn't there a realistic
> >>maximum vector polarization (less than 100%) that one could hope to
> >>obtain???
> >>
> >>the plot versus missing momentum for polarization perpendicular to q
> >>(i.e. the left sector plot) looks especially good for two reasons.
> >>
> >> 1) the asymmetry's "frown" shape for p_m < 0.2GeV shows up very well in
> >> the data.
> >>
> >> 2) though still a little statistics limited, the asymmetry's rise to
> >> positive values for p_m > 0.3GeV is also very visible.
> >>
> >>i would once again remind everyone that much more empty target data is
> >>needed in order to nail down the background contribution at p_m > 0.3GeV.
> >>
> >>aaron
> >>
> >>
>
>



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