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<h1 class="firstHeading">Minutes of the May 4 meeting</h1>
<h3 id="siteSub">From Lowqwiki</h3>
<p>Present: Stepan, Valeri, Hovanes
</p>
<p>On the phone: Lamiaa, Raffaella, Raphael, Eric, Yohann
</p>
<p>Notes by Hovanes
</p>
<p><br>
</p>
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<h2> Pass 0 preparation status </h2>
<ul>
<li> Lamiaa gave an update on the code and calibration status
</li>
<li> There are differences in the time alignment in the monitoring
histograms and the histograms that Lamiaa sees in the calibration code <i>p2p_delay_el</i>.
While the <i>p2p_delay_el</i>
shows that the peaks are centered at zero, the monitoring histograms
show a clear offset and some misalignment between paddles. </li>
<li> The group agreed that the left-right calibrations are
sufficient and there is no need to work more on that. We only need to
fix the paddle-to-paddle calibrations. Hovanes and Lamiaa will
investigate the reason for the differences in the two procedure by the
next meeting. </li>
<li> Raffaella got the scripts for building the C_SQL monitoring web
pages from Mauri. </li>
<li> The <a href="http://www.jlab.org/Hall-B/secure/eg6/cooking/online_sql/monitor.html">eg6 monitoring web page</a>
is ready. Some of the variables are showing no entries on these
histograms. Possible reasons are absence of the numbers in the
database, or just a simple problem with the histogram scale. Raffaella
will look into this.
</li>
</ul>
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<h2> RTPC calibrations with elastic events </h2>
<ul>
<li> Eric is studying the elastic events on the hydrogen target. He
observes shifts in the missing mass of protons by ~4MeV. Posssible
reasons are:
</li>
</ul>
<dl>
<dd>
<ol>
<li> wrongly reconstructed electron momentum in CLAS
</li>
<li> wrongly reconstructed electron angle in CLAS </li>
<li> wrong beam energy </li>
</ol>
</dd>
</dl>
<ul>
<li> Stepan suggested checking if Hall A has beam energy measurements
which would also allow determination of Hall B beam energy.
</li>
</ul>
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