<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal">I think Dennis is correct. This is the likely explanation…..Ken<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><div><div><p class="MsoNormal"><b>From:</b> g12-bounces@jlab.org [mailto:g12-bounces@jlab.org] <b>On Behalf Of </b>Dennis Weygand<br><b>Sent:</b> Monday, March 18, 2013 4:27 PM<br><b>To:</b> Michael C. Kunkel<br><b>Cc:</b> g12@jlab.org<br><b>Subject:</b> Re: [G12] vertex distribution<o:p></o:p></p></div></div><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">OK, I think I got it:<o:p></o:p></p><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal">Your e+ e- gamma sample has a large number of events such that:<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal">1) pi0 --> gamma gamma<o:p></o:p></p></div><div><p class="MsoNormal">2) One of the gamma's converts in material outside of the target<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal">MVRT still has the correct vertex since the e+ e- opening angle is 0.<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal">Dennis<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p><div><div><p class="MsoNormal">On Mar 18, 2013, at 3:52 PM, Michael C. Kunkel wrote:<o:p></o:p></p></div><p class="MsoNormal"><br><br><o:p></o:p></p><div><div><p class="MsoNormal">Greetings, <br><br>I got my hands on PPipPim data to plot the MVRT information. <br>I have posted the plots of the r of MVRT and x vs. y of MVRT for the following topologies: <br><br>Pion; Missing Mass Proton Pi+ Pi- -> 0 (exclusive) <br> Effective Mass Pi+ Pi- ->Omega <br><br>Lepton: Missing Mass Proton e+ e- < Pi0 <br> Missing Mass Proton e+ e- gamma -> 0 (exclusive) <br> Effective Mass e+ e- gamma ->Pi0 <br><br>Plot can be found at<br><a href="https://clasweb.jlab.org/rungroups/g7/wiki/index.php/Reconstruction_study">https://clasweb.jlab.org/rungroups/g7/wiki/index.php/Reconstruction_study</a><br>for March 18, 2013<br><br>Before anyone cries "bug", let me assure everyone that the manner in which the MVRT data is collected for the pions is the same as for leptons, i.e. a clasEvent function. <br><br>From what I deduce, it appears that either exclusive Pi0 production can happen outside of the target (cough cough), or for some reason when the particle is a lepton, we have resolution problems. Neither I can understand from looking at what creates the MVRT. <br><br>Thoughts and help would be appreciated greatly. <br><br>BR <br>MK <br><br><o:p></o:p></p></div><div><p class="MsoNormal">On 3/13/13 3:46 PM, Dennis Weygand wrote:<o:p></o:p></p></div><blockquote><p class="MsoNormal">Does anyone have plots of vertex distributions (z, x vs y, r from MVRT) for any topology? <o:p></o:p></p><div><p class="MsoNormal">Dennis<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p><div><div><div><p class="MsoNormal">--<o:p></o:p></p></div><div><p class="MsoNormal">Dennis Weygand<o:p></o:p></p></div><div><p class="MsoNormal"><a href="mailto:weygand@jlab.org">weygand@jlab.org</a><o:p></o:p></p></div><div><p class="MsoNormal">(757) 269-5926 (office)<o:p></o:p></p></div><div><p class="MsoNormal">(757) 870-4844 (cell)<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal"><br><br><o:p></o:p></p></div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal"><br><br><br><o:p></o:p></p><pre>_______________________________________________<o:p></o:p></pre><pre>G12 mailing list<o:p></o:p></pre><pre><a href="mailto:G12@jlab.org">G12@jlab.org</a><o:p></o:p></pre><pre><a href="https://mailman.jlab.org/mailman/listinfo/g12">https://mailman.jlab.org/mailman/listinfo/g12</a><o:p></o:p></pre></blockquote><p class="MsoNormal"><o:p> </o:p></p></div></div><p class="MsoNormal"><o:p> </o:p></p><div><div><div><p class="MsoNormal">--<o:p></o:p></p></div><div><p class="MsoNormal">Dennis Weygand<o:p></o:p></p></div><div><p class="MsoNormal"><a href="mailto:weygand@jlab.org">weygand@jlab.org</a><o:p></o:p></p></div><div><p class="MsoNormal">(757) 269-5926 (office)<o:p></o:p></p></div><div><p class="MsoNormal">(757) 870-4844 (cell)<o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal"><br><br><o:p></o:p></p></div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal"><o:p> </o:p></p></div></div></body></html>