[BLAST_ANAWARE] more on polarization

From: Tancredi Botto (tancredi@mitlns.mit.edu)
Date: Mon Jul 28 2003 - 12:34:40 EDT


Just one more thought:
I take our number Pzz ca (15 +- 5) % and I get from genya an atomic
fraction of ca. 50-60% (of target nuclei). Both numbers have been
measured in different ways or at different times.

If I am right in my simple arithmetics - even in the scenario that D2
molecules are *completely* unpolarized (50% dilution) - we arrive at an
estimated value of the polarization of incoming ABS atoms of only 30 %.
If BLAST molecules retain 80% of the atomic polarization as at NIKHEF,
then we would get only 17%.

Measuring the target polarization was the point of the analysis of low-Q2
data. It still comes up low with the expected 70% which points to the fact
that there is a problem at the source, before any depolarization in the
cell. Maybe one of the two states is partly (or not) polarized, maybe
both are down by an unknown "efficiency" factor.

regards,
-- tancredi
________________________________________________________________________________
Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
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