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<p>Greetings Andrea, <br>
</p>
It seems that I did not get this email even though you cc'd g12..
Thank you Lei for forwarding it.<br>
I have a few questions about the fitted lines. Are the
representations derived from a projection plot or fitted to the 2D
spectrum?<br>
Also, about the phi corrections, this shape looks very familiar.
Could you do the trivial task of applying the g12 momentum
corrections then comparing the phi of the photon before and after?
As a refresher to the rest of g12, the momentum corrections were
basically a phi correction, see the write-up.<br>
<br>
Otherwise, I am glad that the lepton parameters of the fitter
worked. I was not able to track down why the pion parameters didn't,
as the fitter still works well for me.<br>
<pre class="moz-signature" cols="72">BR
MK
----------------------------------------
Michael C. Kunkel, PhD
Forschungszentrum Jülich
Nuclear Physics Institute and Juelich Center for Hadron Physics
Experimental Hadron Structure (IKP-1)
<a class="moz-txt-link-abbreviated" href="http://www.fz-juelich.de/ikp">www.fz-juelich.de/ikp</a></pre>
<div class="moz-cite-prefix">On 12/19/18 4:20 PM, lguo wrote:<br>
</div>
<blockquote type="cite"
cite="mid:2D754901-850E-415D-81B9-7C36502BA6BF@jlab.org">
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<br class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">Begin forwarded message:</div>
<br class="Apple-interchange-newline">
<div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px;" class=""><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b
class="">From: </b></span><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif;" class="">Andrea Celentano <<a
href="mailto:andrea.celentano@ge.infn.it" class=""
moz-do-not-send="true">andrea.celentano@ge.infn.it</a>><br
class="">
</span></div>
<div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px;" class=""><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b
class="">Subject: </b></span><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif;" class=""><b class="">Re: [G12] Meeting
reminder</b><br class="">
</span></div>
<div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px;" class=""><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b
class="">Date: </b></span><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif;" class="">December 19, 2018 at 4:39:29 AM EST<br
class="">
</span></div>
<div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px;" class=""><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b
class="">To: </b></span><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif;" class="">lguo <<a
href="mailto:lguo@jlab.org" class=""
moz-do-not-send="true">lguo@jlab.org</a>><br class="">
</span></div>
<div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px;" class=""><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b
class="">Cc: </b></span><span style="font-family:
-webkit-system-font, Helvetica Neue, Helvetica,
sans-serif;" class="">g12 <<a
href="mailto:g12@jlab.org" class=""
moz-do-not-send="true">g12@jlab.org</a>><br class="">
</span></div>
<br class="">
<div class=""><br>
</div>
</blockquote>
</div>
Dear G12,
<div class="">I’ll be on a train starting from 10AM JLAB time,
hence I don’t know if I’ll be able to join the meeting - will
try, but I don’t know about the quality of internet connection
via phone.</div>
<div class=""><br class="">
</div>
<div class="">Concerning meeting time next year, these are my
options:</div>
<div class=""><br class="">
</div>
<div class="">Monday: from 8 AM to 12 AM</div>
<div class="">Tuesday: from 8 AM to 12 AM</div>
<div class="">Wednsday: from 8 AM to 11.30 AM</div>
<div class="">Thursday: from 8 AM to 11 AM</div>
<div class="">Friday: from 8 AM to 11 AM</div>
<div class=""><br class="">
</div>
<div class="">Concerning g12 photons, I realized that is not
trivial to isolate in the dataset a clean sample of gamma p
-> p pi+ pi- gamma events. I was relying on kin. fit to do so
(as done by D. Keller for his g11 corrections), selecting events
with an high (>15%) CL for the gamma p -> p pi+ pi-
(gamma) hypothesis and a low (<1%) CL for the missing pi0
hypothesis. However, when comparing the measured gamma with the
kin.fit missing gamma, I saw very broad distributions.</div>
<div class=""><br class="">
</div>
<div class="">Therefore, I tried to repeat the procedure on the
reaction gamma p -> pi pi0 -> p e+ e- gamma. I used the
same skim as before, assigning to pi+ the e+ mass and to pi- the
e- mass and correcting the energy (not the momentum), as
suggested by MK. I saw a clean pi0 peak in the missing mass on
the proton, and I selected events by applying a 2C kin. fit on
the gamma p -> pi e+ e- (gamma) hypothesis, constraining the
e+ e- gamma to form a pi0.e</div>
<div class=""><br class="">
</div>
<div class="">After doing so, I was able to select a very clean
set of events. The pulls and the chi2 prob. distribution look
fine. I am now in the process of deriving the corrections. I
attach a screenshot showing the difference between missing
photon energy/angles minus measured photon energy/angles as a
function of the missing photon quantities. </div>
<div class=""><br class="">
</div>
<div class="">Bests,</div>
<div class="">Andrea</div>
</blockquote>
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