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    <p>Please find the minutes for the meeting held earlier this week <a
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href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_December_17,_2019#Minutes">here</a>
      and below.</p>
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          <h2 id="firstHeading" class="firstHeading" lang="en"><span
              dir="auto">HDGeant4 Meeting, December 17, 2019, </span><span
              class="mw-headline" id="Minutes">Minutes</span></h2>
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              <p>Present:
              </p>
              <ul>
                <li> <b> CMU: </b> Naomi Jarvis</li>
                <li> <b> JLab: </b> Alex Austregesilo, Mark Dalton,
                  Colin Gleason, Mark Ito (chair), Keigo Mizutani, Simon
                  Taylor</li>
                <li> <b> UConn: </b> Richard Jones</li>
              </ul>
              <p>There is a <a rel="nofollow" class="external text"
                  href="https://bluejeans.com/s/Eum3E/">recording of
                  this meeting</a> on the BlueJeans site. Use your JLab
                credentials to get access.
              </p>
              <h3><span class="mw-headline"
                  id="Review_of_Minutes_from_the_December_3_Meeting">Review
                  of Minutes from the December 3 Meeting</span></h3>
              <p>We went over <a
href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_December_3,_2019#Minutes"
                  title="HDGeant4 Meeting, December 3, 2019">the minutes</a>.
                Alex will close <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/125">the issue on
                  neutron generation</a>.
              </p>
              <h3><span class="mw-headline" id="genBH_Output_Format">genBH
                  Output Format</span></h3>
              <p>At the last software meeting Mark D. reported problems
                reading the output from the genBH generator. The code is
                in the HDGeant4 repository. Richard was able to
                reproduce the problem and submitted <a rel="nofollow"
                  class="external text"
                  href="https://github.com/JeffersonLab/HDGeant4/pull/135">a
                  pull request</a> that fixes the problem.
              </p>
              <h3><span class="mw-headline" id="Issues_on_GitHub">Issues
                  on GitHub</span></h3>
              <p>We went over <a rel="nofollow" class="external text"
                  href="https://github.com/JeffersonLab/HDGeant4/issues">the
                  issues</a>. Most of the time was spent discussion <a
                  rel="nofollow" class="external text"
                  href="https://github.com/JeffersonLab/HDGeant4/issues/111">Issue
                  #111</a>, "Difference in Acceptance between G3 and
                G4". Colin led the discussion.
              </p>
              <ul>
                <li> Colin went back and revisited his study from last
                  May with recent versions of software.</li>
                <li> When looking at the comparison of efficiency as a
                  function of eta-pi mass, the agreement is between G3
                  and G4 is reasonable, but when viewed as a function of
                  cosθ<sub>GJ</sub> there is a noticeable difference
                  between the forward and backward directions (at 7:17
                  in the recording). This is similar to the results of
                  the original study and the initial cause of concern.
                  Colin noted that the data is more similar to the G3
                  efficiency as opposed to that for G4.</li>
                <li> Mark Dalton pointed out that in this and other
                  efficiency studies, the overall event acceptance is
                  less that that one would expect from single particle
                  studies.</li>
                <li> After sorting through some some confusion, we
                  concluded that the single particle yield comparisons
                  that were shown are actually after the events are
                  accepted by the analysis library. This means that they
                  reflect not only the efficiency of the particle shown,
                  but the overall event efficiency. In particular
                  differences in the efficiencies for one type of
                  particle will effect the apparent comparative yield of
                  other particle types.</li>
                <li> Alex suggested that the problematic effect might
                  also the the effect of timing cuts placed on charged
                  particles in the calorimeters, a problem he
                  illustrated in his post to <a rel="nofollow"
                    class="external text"
                    href="https://github.com/JeffersonLab/HDGeant4/issues/93">Issue
                    #93</a>. Colin will pursue this possibility, in
                  particular repeating the analysis with looser timing
                  cuts on matching between charged tracks and
                  calorimeter clusters.</li>
                <li> Eugene Chudakov made a suggestion to Colin: do the
                  G3 vs. G4 comparison with the same input events and
                  see where the differences occur on an event-by-event
                  basis. Perhaps a pattern will emerge.</li>
              </ul>
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              Retrieved from "<a dir="ltr"
href="https://halldweb.jlab.org/wiki/index.php?title=HDGeant4_Meeting,_December_17,_2019&oldid=95541">https://halldweb.jlab.org/wiki/index.php?title=HDGeant4_Meeting,_December_17,_2019&oldid=95541</a>"</div>
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          <li id="lastmod"> This page was last modified on 20 December
            2019, at 12:17.</li>
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