<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Lei, Carlos explained it correctly. It should be electron beam energy, which is a constant. </div><div><br></div><div data-marker="__SIG_PRE__">-Eugene</div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="border-left: 2px solid #1010FF; margin-left: 5px; padding-left: 5px; color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><b>From: </b>"Lei Guo" <lguo@jlab.org><br><b>To: </b>"Carlos Salgado" <salgado@jlab.org><br><b>Cc: </b>"g12@jlab.org g12@jlab.org" <g12@jlab.org><br><b>Sent: </b>Wednesday, February 10, 2016 2:49:16 PM<br><b>Subject: </b>Re: [G12] resolution of tagger in kinematic fitter<br></blockquote></div><div data-marker="__QUOTED_TEXT__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="border-left: 2px solid #1010FF; margin-left: 5px; padding-left: 5px; color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;">That’s fine except the E_beam here should be the Energy of the photon, instead the constant (of the electron beam energy) that’s now used in the code. Did I get that wrong?<div class=""><br class=""></div><div class="">Lei</div><div class=""><br class=""><div class=""><div class=""><div class=""><div class="">Lei Guo</div><div class="">Assistant Professor</div><div class="">Physics Department</div><div class="">Florida International University</div><div class="">Miami, FL</div></div><div class=""><br class=""></div><div class="">email: <a href="mailto:leguo@fiu.edu" class="" target="_blank" data-mce-href="mailto:leguo@fiu.edu">leguo@fiu.edu</a> or <a href="mailto:lguo@jlab.org" class="" target="_blank" data-mce-href="mailto:lguo@jlab.org">lguo@jlab.org</a></div><div class="">Office:305-348-0234</div></div></div><br class=""><div><blockquote class=""><div class="">On Feb 10, 2016, at 12:39 PM, Carlos Salgado <<a href="mailto:salgado@jlab.org" class="" target="_blank" data-mce-href="mailto:salgado@jlab.org">salgado@jlab.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">Hi<br class=""><br class="">Follow the discussion in last g12 meeting.<br class=""><br class="">The formula in the code for the variance of the photon bean energy is OK.<br class=""><br class="">The uncertainty in the energy of the photon is 0.001* E_beam (per NIM and Eugene P.) The hodos were built such that this is true (different widths)<br class=""><br class="">Then consider a counter of width (energy) "a" where the (assume) energy distribution is flat: then Variance = sigma^2 = 1/a* int^a_0 E^2 dE = a^2/3<br class=""><br class="">Therefore if we distribute the uncertainty over a counter (energy bin) the variance is : sigma^2 = (0.001*E_beam)**2/3<br class=""><br class="">=Carlos<br class="">_______________________________________________<br class="">G12 mailing list<br class=""><a href="mailto:G12@jlab.org" class="" target="_blank" data-mce-href="mailto:G12@jlab.org">G12@jlab.org</a><br class="">https://mailman.jlab.org/mailman/listinfo/g12<br class=""></div></blockquote></div><br class=""></div><br>_______________________________________________<br>G12 mailing list<br>G12@jlab.org<br>https://mailman.jlab.org/mailman/listinfo/g12<br></blockquote></div></div></body></html>