Re: [BLAST_ANAWARE] rates and polarization

From: Chi Zhang (zhangchi@MIT.EDU)
Date: Tue Jul 06 2004 - 22:46:38 EDT


I have built false asymmetries and they are consistant with 0. ofcourse
error is sizible. the false asymetries I build are(as I showed in one of
the big anal meeting): tensor asymmetry with the two vector states which
are both tensor +. Vector asyemmetry using only the tensor '-' state and
the two beam helicity.

So may i say false asym is checked?

Chi

On Tue, 6 Jul 2004, Tancredi Botto wrote:

>
>
> Hi chi, blasters
> unfortunately for all runs after the shutdown we do have an intermittent
> problem with daq such that valid triggers have no tdc info. This may
> occurr on both the tof's and the neutron counters, and propagates to
> the ntuples. You can check either with raw data or with something like
>
> Draw("ttr","trig==1&&ntl<16&&ntr<16") (see also elog)
>
> obviously these events must have a valid tdc hit. You will find that
> most likely ttr is missing, may also be ttl. So all considerations about
> rates are pretty much up in air.
>
> About polarization: although this daq problem is not immediately
> spin-dependent (..) it will nevertheles be like so for a small sample of
> runs or flips. In other words, you start building false asymmetries if
> you have a few good runs and bad runs, given the fact that we actually
> flip a few times per run.
>
> -- tancredi
> ________________________________________________________________________________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> On Tue, 6 Jul 2004, Chi Zhang wrote:
>
> >
> > Hi, sorry for using the wrong runs. I don't know what I was thinking.
> >
> > checked, Pzz I sent out yesterday was done with the "fixed" runs. results
> > from 8479-8598:
> >
> > D in left 4479, D in right 5103, total charge 18646 C, 0.51 counts/C
> > not a significant increase still. Am I still wrong with the runs and
> > charge?
> >
> > Pzz: 58.0+-4.7%. Better than ever before. But still not consistant with
> > Genya's mid 80%. Maybe he has new updates by now.
> >
> > Chi
> >
> > PS. these are the run numbers I used, please do let me know if I am using
> > bad runs or you find I m having wrong charge integrations.
> > 8479-8486 8488-8494 8496 8500-8513 8515-8522 8524-8531 8533-8535 8537-8540
> > 8543-8554 8564-8568 8570-8583 8585-8588 8592 8594-8598
> >
> > 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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