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<div class="moz-cite-prefix">Hi Volker,<br>
<br>
This enhancement at 1020MeV might be a phi. Since the eta is
missing maybe a photon got misinterpreted as an eta. The phi(1020)
goes to pi pi gamma. But this peak gets totally suppressed after
the Q-value method, so every misinterpreted gamma gets suppressed.
I think I mentioned this problem during my talk, but maybe I
forgot. <br>
The text says right, maybe I misplaced the line a little bit. <br>
For the plots your are asking for:<br>
1) I cutted on the pi0 in the missing mass. The beam energy is as
suggested. Tha angular distribution are in lab frame. Is this what
you wanted or do you want it in the cms frame?<br>
2) I cutted on the eta in the missing mass.The beam energy is: ,
due to statistics I had to go higher to 1.7GeV <E_gamma
<1.8 GEV. Also lab frame.<br>
You could find them here: <a class="moz-txt-link-abbreviated"
href="http://www.ep1.rub.de/%7Ecathrina">www.ep1.rub.de/~cathrina</a><br>
<br>
<br>
Cheers,<br>
Cathrina<br>
<br>
On 07/16/15 23:20, Volker Crede wrote:<br>
</div>
<blockquote cite="mid:C38F960D-8285-42AA-A520-8327334E785F@fsu.edu"
type="cite">
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Hi Cathrina,
<div><br>
</div>
<div>I also have a question, something I did not notice at the
collaboration meeting. On Slide 14, you are showing the
unweighted "pi pi eta" invariant mass which exhibits a clear
peak for the eta' including background just below 0.96 GeV …
However, there is another peak at 1.02 GeV = 1020 MeV = mass of
the phi meson. Why do you see a peak at 1020 MeV or am I missing
something? According to the text, the cut on the eta' is 0.9 GeV
< m < 1.02 GeV but in the plot, the cut is 0.9 GeV < m
< 1.0 GeV. </div>
<div><br>
</div>
<div>At FSU, we have found recently (this week) massive holes in
the 3pi mass distributions close to the omega threshold and in
the forward direction. Unfortunately, this affects our cross
section below 1.5 GeV in photon energy. This could be similar to
a discussion we had in FROST a while ago and be related to
inefficiencies in the drift chamber:</div>
<div><br>
</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>* Would
you have a plot of your 3pi mass distribution, perhaps for 1300
- 1400 MeV in incoming photon energy and cos(theta_3pi) >
0.5?</div>
<div><br>
</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>*
And a similar distribution for the "pi pi eta" invariant mass in
the forward direction, perhaps 200 - 300 MeV above the eta'
threshold?</div>
<div><br>
</div>
<div>Cheers,</div>
<div><br>
</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>Volker</div>
<div><br>
</div>
<div><br>
<div>
<div>On Jul 16, 2015, at 4:14 PM, Lei Guo <<a
moz-do-not-send="true" href="mailto:lguo@jlab.org">lguo@jlab.org</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
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charset=utf-8">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;" class="">Hi,
Cathrina,
<div class=""><br class="">
</div>
<div class="">Did you apply the track-dependent efficiency
correction that g12 has been using (developed by MK)?
You have three tracks in your final state, and that
correction can add up to around 18% for some kinematic
bins.</div>
<div class=""><br class="">
</div>
<div class="">Lei</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
<div apple-content-edited="true" 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 moz-do-not-send="true"
href="mailto:leguo@fiu.edu" class="">leguo@fiu.edu</a> or
<a moz-do-not-send="true"
href="mailto:lguo@jlab.org" class="">lguo@jlab.org</a></div>
<div class="">Office:305-348-0234</div>
</div>
</div>
<br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Jul 16, 2015, at 3:48 PM, Eugene
Pasyuk <<a moz-do-not-send="true"
href="mailto:pasyuk@jlab.org" class="">pasyuk@jlab.org</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">Dear Cathrina,<br class="">
<br class="">
Can you briefly explain how did you resolve the
issue with the energy dependent scaling factor you
had. What was the problem?<br class="">
Even though you eliminated this energy dependent
normalization factor there are still some
discrepancies between g11 and g12 cross sections.
Sometimes as large as 20% or even more. Log scale
somewhat hides it but it is there. This needs to
be studied further. <br class="">
I think you can show your cross sections but have
to be careful with your statement. You may say
that in general the shape of the angular
distribution agrees well between the two datasets.
Some discrepancies are present and being
investigated. Since this is preliminary data make
sure that all you cross section plots are labeled
as preliminary. Once you have your slides prepared
please distribute them before the conference.<br
class="">
<br class="">
And one more suggestion for the future. Our
mailing lists have limitations on the maximum size
of the message.<br class="">
I believe it is 40 kB or so. If you want to share
some files post them on the web somewhere and
include the link in you mailing list post.<br
class="">
<br class="">
Cheers,<br class="">
<br class="">
-Eugene<br class="">
<br class="">
----- Original Message -----<br class="">
<blockquote type="cite" class="">From: "Cathrina
Sowa" <<a moz-do-not-send="true"
href="mailto:cathrina@ep1.ruhr-uni-bochum.de"
class="">cathrina@ep1.ruhr-uni-bochum.de</a>><br
class="">
To: "Eugene Pasyuk" <<a
moz-do-not-send="true"
href="mailto:pasyuk@jlab.org" class="">pasyuk@jlab.org</a>>,
"DEVITA" <<a moz-do-not-send="true"
href="mailto:devita@ge.infn.it" class="">devita@ge.infn.it</a>>,
<a moz-do-not-send="true"
href="mailto:jordanka@physics.sc.edu" class="">jordanka@physics.sc.edu</a>,
"<a moz-do-not-send="true"
href="mailto:g12@jlab.org" class="">g12@jlab.org</a><br
class="">
<a moz-do-not-send="true"
href="mailto:g12@jlab.org" class="">g12@jlab.org</a>"
<<a moz-do-not-send="true"
href="mailto:g12@jlab.org" class="">g12@jlab.org</a>>,
"clas lmd" <<a moz-do-not-send="true"
href="mailto:clas_lmd@jlab.org" class="">clas_lmd@jlab.org</a>><br
class="">
Sent: Thursday, July 16, 2015 10:00:57 AM<br
class="">
Subject: Review of analysis procedure<br
class="">
</blockquote>
<br class="">
<blockquote type="cite" class="">Dear colleagues,<br
class="">
<br class="">
I would like to present preliminary results of
the analysis (gamma p -><br class="">
p pi+ pi- (eta))<br class="">
I am working on at a parallel session at the
upcoming EUNPC 2015<br class="">
conference in Groningen.<br class="">
<br class="">
The analysis was presented at the CLAS
collaboration meeting in June at the<br class="">
the Hadron Spectroscopy session [1]. All
concerns and comments raised<br class="">
during the<br class="">
discussion after the talk have been considered.
The energy dependent<br class="">
scaling factor for<br class="">
the differential cross section for example is
now no longer needed.<br class="">
<br class="">
In order to follow the required procedure,
Johann and Mario advised me to<br class="">
discuss the updated analysis with the g12 run
group. Below I prepared a<br class="">
summary of the<br class="">
data selection and preliminary results I would
like to include in my<br class="">
presentation.<br class="">
<br class="">
I would be happy about any comments and
suggestions from your side.<br class="">
<br class="">
Best regards,<br class="">
Cathrina<br class="">
<br class="">
[1]: <a moz-do-not-send="true"
href="https://www.jlab.org/Hall-B/secure/hadron/meetings/18jun15/sowa.pdf"
class="">https://www.jlab.org/Hall-B/secure/hadron/meetings/18jun15/sowa.pdf</a><br
class="">
<br class="">
<br class="">
MOTIVATION<br class="">
Study of excited eta states in photo production,
with<br class="">
emphasis on the production of the glueball
candidate eta(1405). The<br class="">
eta(1405)<br class="">
production in photo-production can be compared
to its production in<br class="">
gluon-rich processes to shed further light on
its nature.<br class="">
<br class="">
As a reference and validation for the upper
limit of the eta(1405) cross<br class="">
section, the<br class="">
eta' differential cross section will be
determined and compared to the<br class="">
published g11<br class="">
results.<br class="">
<br class="">
<br class="">
DATA<br class="">
- run numbers: 56520-56572, 56573-56594,
56608-56646 which were<br class="">
event-sorted<br class="">
according to 2-2pos1neg_not_1ckaon1ctrk<br
class="">
<br class="">
- fulfilling the same trigger conditions: 3
charged tracks in 3<br class="">
different sectors or<br class="">
2 charged track in 2 different sectors with a
beam energy above 3.6 GeV<br class="">
<br class="">
EVENT SELECTION<br class="">
- two positively-charged tracks for the proton
and the pi+ as well as<br class="">
one negatively-charged track for the pi−.<br
class="">
<br class="">
- g12_ecor.hpp package is used for the beam
energy corrections<br class="">
<br class="">
- g12_pcor.hpp package is used for momentum
correction<br class="">
<br class="">
- Energyloss was accounted with the the standard
eloss corrections<br class="">
<br class="">
- All three particles correspond to the same
beam photon<br class="">
<br class="">
- Standard cuts on vertices (Fig1, Fig2),
minimum momenta(Fig3), beta Vs<br class="">
momentum(Fig4), fiducial volume (Fig5) and
timing (Fig6) are included<br class="">
<br class="">
- Q-value method applied on the missing eta to
achieve a better<br class="">
background suppression (Fig7) (Black: Before,
Blue: 1-Q weighted, Red: Q<br class="">
weighted)<br class="">
<br class="">
<br class="">
PRELIMINARY RESULTS<br class="">
<br class="">
Fig8: inv. eta pi+ pi- mass spectrum<br class="">
<br class="">
red w/ error bars: w/o Q-weight; blue:
Q-weighted<br class="">
<br class="">
Fig9: differential eta' cross section<br
class="">
- GEANT based Monte Carlo events are used for
efficiency correction<br class="">
following the procedure documented in the g12
wiki<br class="">
<br class="">
- The photon flux is obtained as described in
the g12 wiki<br class="">
<br class="">
- To compare to the published g11 results, the
same W binning is used<br class="">
<br class="">
Fig8: Comparison of the diff. eta' cross section
for g11 (pink) and g12<br class="">
(black) data<br class="">
The distributions are in good agreement now.<br
class="">
<br class="">
--<br class="">
M.Sc. Cathrina Sowa<br class="">
Ph. D. student<br class="">
Institut für Experimentalphysik I<br class="">
Ruhr-Universität Bochum<br class="">
Universitätsstr. 150<br class="">
44801 Bochum<br class="">
<br class="">
Office: NB 2/74<br class="">
Tel.: 0234-32-23564<br class="">
Web: <a moz-do-not-send="true"
href="http://www.ep1.rub.de/" class="">www.ep1.rub.de</a><br
class="">
</blockquote>
<br class="">
_______________________________________________<br
class="">
Clas_lmd mailing list<br class="">
<a moz-do-not-send="true"
href="mailto:Clas_lmd@jlab.org" class="">Clas_lmd@jlab.org</a><br
class="">
<a moz-do-not-send="true"
href="https://mailman.jlab.org/mailman/listinfo/clas_lmd">https://mailman.jlab.org/mailman/listinfo/clas_lmd</a><br
class="">
</div>
</blockquote>
</div>
<br class="">
</div>
</div>
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<pre class="moz-signature" cols="72">--
M.Sc. Cathrina Sowa
Ph. D. student
Institut für Experimentalphysik I
Ruhr-Universität Bochum
Universitätsstr. 150
44801 Bochum
Office: NB 2/74
Tel.: 0234-32-23564
Web: <a class="moz-txt-link-abbreviated" href="http://www.ep1.rub.de">www.ep1.rub.de</a> </pre>
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