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Matt,</div>
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Slide 4 shows that the current energy dependence parametrization is wrong above 4 GeV or this behavior is due to overlapping clusters? If it is the latest, how can you be sure that the current parametrization is correct?<br>
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tks ig.<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Shepherd, Matthew <mashephe@indiana.edu><br>
<b>Sent:</b> Friday, May 1, 2020 10:07 AM<br>
<b>To:</b> Igal Jaegle <ijaegle@jlab.org><br>
<b>Cc:</b> Hall-D Calorimetry <halld-cal@jlab.org><br>
<b>Subject:</b> Re: [Halld-cal] [EXTERNAL] FCAL calibration follow-up</font>
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<div class="">Igal,</div>
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Because the pi0 fitting (which is of poor quality) is systematically biased by 1 to 2 MeV when he doing the energy dependence correction the pi0 mass is shifted to lower mass and falls within 2-3% around the pi0 PDG mass and stops there. </div>
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<div class="">Please reference:</div>
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<div class=""><a href="https://halldweb.jlab.org/DocDB/0043/004387/001/presentation.pdf" class="">https://halldweb.jlab.org/DocDB/0043/004387/001/presentation.pdf</a></div>
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<div class="">The left plot of slide 4 shows that if the average energy for photons used in making the pi0 peak varies, then the pi0 peak will vary by about +/- 1.5%. The pi0 mass on the left of slide 2 clearly averages over energies in a way that is location
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It happens even with perfect fitting and in the absence of systematic bias. It is a pure byproduct of energy non-linearity and variation in average energy of photons from pi0 decays.
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<div class="">Matt</div>
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