Hello John,
in a subsequent email chris has shown that with the - by now - known (and
equal) hydrogen vector polarizations at 32 and 45 deg spin angle the Ge/Gm
error improves by a factor of 0.73 - 0.83. Me and chris have just run a
similar analysis for N-Delta.
The 2 asymmetries there can be used to extract Rtt' (spin parallel kin,
\propto M1) and Rlt' terms (spin perp, \propto E2,C2). Spin parallel and
perp take a different meaning here because the q-direction is forward
(experience says 30 deg). So with help from MAID partial cross section the
error propagation goes like this (in a.u.)
spin 32 deg: delta_Alt' ~ 10.0 delta_Att' ~ 13.1
spin 45 deg: delta_Alt' ~ 12.2 delta_Att' ~ 8.5
clearly at 32 deg one would hope for a better measurement of the E2,C2
terms by about 20 %. This is way 32 deg is preferrable - i think - for
N-delta.
As a collaboration we said we were going to discuss this, and here are
the numbers. I am sure richard could help here.
We are now measuring at 32 deg only for the sake of measuring the
same asymmetries and in the same set-up as for the D2 run (as you know
the 32 deg proton asymmetry is important for d2).
regards
-- tancredi
________________________________________________________________________________
Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
On Sun, 31 Oct 2004, John Calarco wrote:
>
> Hi Tancredi,
>
> Chris has shown that the target polarization at 45 deg is as at least
> as good as at 32 deg. As one of the spokespersons for the hydrogen
program
> I request that we continue at 45 deg.
>
> John
>
>
>
>
> On Sun, 31 Oct 2004, Electronic Log Book wrote:
>
> > Operator: tancredi
> >
> > Continued ABS data but as ABS was losing intensitiy very rapidly (see
> > http://blast02.lns.mit.edu/elog/2004/10/31/30644.html ) decided to switch to
> > empty at around 10 am and started cycling nozzle.
> >
> > Lost about 2 hours due to network problems. Hopefully they had been solved
> > now that barbara idenitifed a troublesome network switch. Tried to take
> > data in the meantime but roc got disconnected and could not reboot until
> > network came back
> >
> > Now genya is starting He3 program. Plan is to go back to 32 deg hydrogen
> > for the night
> >
> >
> >
>
>
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