<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
<p>Folks,</p>
<p>These minutes are from Tuesday, a week ago. Please find them <a
moz-do-not-send="true"
href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_January_28,_2020#Minutes">here</a>
and below.</p>
<p> -- Mark</p>
<p>
</p>
<div id="globalWrapper">
<div id="column-content">
<div id="content" class="mw-body" role="main">
<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">HDGeant4 Meeting, January 28, 2020, </span><span
class="mw-headline" id="Minutes">Minutes</span></h1>
<div id="bodyContent" class="mw-body-content">
<div id="mw-content-text" dir="ltr" class="mw-content-ltr"
lang="en">
<p>Present:
</p>
<ul>
<li> <b> CMU: </b> Naomi Jarvis</li>
<li> <b> FSU: </b> Sean Dobbs</li>
<li> <b> JLab: </b> Alex Austregesilo, Colin Gleason,
Mark Ito (chair), Simon Taylor, Beni Zihlmann</li>
<li> <b> UConn: </b> Richard Jones, James McIntyre</li>
<li> <b> W&M: </b> Justin Stevens</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/1M0qK/">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_last_Meeting">Review of
minutes from the last Meeting</span></h3>
<p>We went over <a
href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_January_14,_2020#Minutes"
title="HDGeant4 Meeting, January 14, 2020">the minutes
from January 14</a>.
</p>
<h4><span class="mw-headline"
id="Calorimeter_timing_mismatch_between_g3_and_g4">Calorimeter
timing mismatch between g3 and g4</span></h4>
<p>This is <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/93">Issue
#93</a>.
</p>
<p>Colin has extended his work on this issue, widening the
timing cuts as Alex did for his ρ analysis. He sees
indeed that G3 and G4 both have significant tails in
BCAL timing for π<sup>−</sup>s, with the tail bigger for
G3.
</p>
<p>When looking at acceptance for the full reaction (pγ→ηπ<sup>−</sup>Δ<sup>++</sup>)
as function of Gottfried-Jackson angle the differing
shapes remain, except the G4 efficiency drops in level
from about 4% to 2.5% while retaining its overall shape.
Alex saw a similar effect in the ρs until he fixed the
bug whereby the choice of RF bunch was defeated by a
lack of agreement among multiple tracks inside the wide
timing window. Colin will go back and repeat his study
with the current master branch of halld_recon.
</p>
<h3><span class="mw-headline"
id="Systematic_studies_of_Geant3.2FGeant4_differences">Systematic
studies of Geant3/Geant4 differences</span></h3>
<p>Alex presented Igal's work on Monte Carlo studies of
γp→ωp and ω→π<sup>+</sup>π<sup>−</sup>π<sup>0</sup>;. He
compared simulations with:
</p>
<ul>
<li> G3 vs. G4</li>
<li> no accidental background events, background from
Richard's MC beam background generator, and random
trigger events mixed in</li>
<li> run 30496 vs. run 30730</li>
</ul>
<p>for a total of twelve different sets of conditions. He
showed a variety of different comparisons among these
conditions including single particle distributions,
invariant mass distributions and occupancy plots for the
FCAL. Please <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/DocDB/0043/004314/001/primexd-igal-jaegle-27012020.pdf">see
his slides for the rich variety of comparisons
available</a>. From Igal's last slide, here are his
conclusions:
</p>
<ul>
<li> Low-level systematic comparisons between different
Geant versions and runs, and with and without
background combined: Geant3 and Geant4 show clear
difference without any backgrounds included
<ul>
<li> More photons/hits are produced in Geant4
(observed mostly in FCAL due possibly to ω
physics/decay)</li>
</ul>
</li>
<li> All the other differences listed below are
happening outside of Geant Without backgrounds (but
also with backgrounds)
<ul>
<li> Calibration tables although identical are
applied differently to Geant3 and Geant4
simulations possibly because they are not applied
at the same variable(s)?</li>
</ul>
</li>
<li> Combination of background/noise to simulation
produces different outcome for Geant3 and Geant4
simulations</li>
<li> Combination of background/noise to Geant3
simulations are consistent and evenly distributed
=> seems correct</li>
<li> Combination of background/noise to Geant4
simulations are inconsistent and not evenly
distributed
<ul>
<li> Background/noise mostly located at the edge and</li>
<li> Creates spikes</li>
<li> => seems buggy</li>
</ul>
</li>
<li> As the same code is used to combine the
background/noise to both simulation version, it
probably means it is not using the same variable(s)?</li>
</ul>
<h3><span class="mw-headline" id="Collaboration_Meeting">Collaboration
Meeting</span></h3>
<p>We need to make some sort of report out of this group
on work since the last collaboration meeting. Mark and
Sean will get together and discuss options. Stay tuned.
</p>
</div>
<div class="printfooter">
Retrieved from "<a dir="ltr"
href="https://halldweb.jlab.org/wiki/index.php?title=HDGeant4_Meeting,_January_28,_2020&oldid=96324">https://halldweb.jlab.org/wiki/index.php?title=HDGeant4_Meeting,_January_28,_2020&oldid=96324</a>"</div>
</div>
</div>
</div>
<div id="footer" role="contentinfo">
<ul id="f-list">
<li id="lastmod"> This page was last modified on 4 February
2020, at 14:38.</li>
</ul>
</div>
</div>
</body>
</html>