Hi,
I wanted to follow up on the results shown yesterday for the beam
asymmetry. Basically, chris analysis was based on four fills only.
However (not to his fault, but rather to mine) for those runs the
beam-gate inhibited charge was counting charge when coda was dead
(the TS live out going to the scaler inhibit).
In principle this is not a problem, when you realize that
Q_not/Q_tot = 0.8 is the livetime not the deadtime. However, in our
setup it so happens that in this configuration we count charge also
when filling the ring.
So I did another analyisis: for each fil we have a different beam
helicity. I slice over an even number of fill and only look for events
that occured in the same range of beam current. As long as the lifetime
was constant (and in practice it is) both h+ and h- have the same charge.
Then I plot coplanar events. All coplanar events (elastic or not) should
have zero asymmetry. Indeed, summing through many paddles and 3 runs I get
the following (coinc with tof0-5 only)
Helicity L (11-15) R (11-15)
"+" 1638 1670
"-" 1582 1667
So the "+" and "-" asymmetries are all consistent with zero. Note,
I had no cuts on coplanarity !
We'll have to take a better look when beam comes back on
-- ________________________________________________________________________________ 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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