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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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