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Greetings,<br>
<br>
I will try to find a configuration file to look into, but that is
about all I know what to do.<br>
<br>
BR<br>
MK<br>
<br>
<div class="moz-cite-prefix">On 2/19/14 4:54 PM, Jason Bono wrote:<br>
</div>
<blockquote cite="mid:51FDF5AF-D7BE-49F4-AA70-391519FCFEB1@jlab.org"
type="cite">Hello all,
<div>
<div>As i had mentioned at our meeting, before i had to hang up
and run for my life, that I'm looking into the sign of the
electron helicity. This info was stored in the HEAD bank under
EVTCLASS for other experiments .</div>
</div>
<div>for example one experiment had:</div>
<div><br>
</div>
<div>EVTCLAS= 1,2 or 11 for positive helicity.</div>
<div>and,</div>
<div>EVTCLAS= 4,5 or 14 for negative helicity.</div>
<div><br>
</div>
<div> From a bosdump over various g12 runs i see that EVTCLASS=14
for the vast majority of the data. This could mean one of two
things:</div>
<div><br>
</div>
<div>1) The true electron helicity is overall negative meaning
that g12 did not collect data with a helicity flip rate during
production runs (other experiments did with a rate of 30HZ which
give net zero helicity, even for polarized experiments)</div>
<div>2) The reliable event by event electron helicity information
is actually not stored in the EVTCLASS or the convention is
different.</div>
<div><br>
</div>
<div>Can anyone verify 1? This would explain why the moller
measurements are consistently negative as well. However it was
my understanding that MCC <b>had</b> to flip the helicity. </div>
<div>if 2, Does anyone know where i can learn about the convention
used by g12? All i can see from the CLAS online BOS viewer is
that EVTCLASS=1-15 means "Physics Events".</div>
<div><br>
</div>
<div>Any input would be appreciated and if i am not clear please
ask me to elaborate.</div>
<div>Regards,</div>
<div>Jason</div>
<br>
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