<div dir="ltr"><div class="gmail_quote"><div dir="ltr">Curtis,<div><br></div><div>The typical time scale for pi- capture is 1ps, not 1ns (see reference 1 below). But there are metastable states that affect a few percent of the stopped pions, leading to 10ns delays for a few percent of them. This was first noticed in liquid helium (see reference 2 below), and turned out to be understood as capture to Rydberg states around N~15. An experiment at TRIUMF was performed to measure the effect in water (see reference 3 below) but I don't remember what the results showed. This should only affect a few percent of the stopped pions.</div>
<div><ol><li><a href="http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/StrauchDiss.pdf">http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/StrauchDiss.pdf</a><br></li><li><a href="http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/PhysRevA.45.6202.pdf">http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/PhysRevA.45.6202.pdf</a><br>
</li><li><a href="http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/paper_1402630812.pdf">http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/paper_1402630812.pdf</a><font color="#888888"><br>
</font></li></ol><font color="#888888"><div>-Richard Jones</div></font></div><div><br></div>
</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jun 13, 2014 at 6:14 AM, Curtis A. Meyer <<a href="mailto:cmeyer@cmu.edu">cmeyer@cmu.edu</a>> wrote:<br>
<blockquote class="gmail_quote"><div>Hi Richard -<div><br></div><div> From my p-bar days, I would have thought the time scales were sub-ns on these processes.</div>
<div>Will sees them from ~ns to perhaps 10-15 ns. </div><div><br></div><div> Curtis<br><div>
<div>
<div>-------</div><div>Prof. Curtis A. Meyer Department of Physics</div><div>Phone: <a href="tel:%28412%29%20268-2745">(412) 268-2745</a> Carnegie Mellon University</div>
<div>Fax: <a href="tel:%28412%29%20681-0648">(412) 681-0648</a> Pittsburgh, PA 15213</div><div><a href="mailto:curtis.meyer@cmu.edu">curtis.meyer@cmu.edu</a> <a href="http://www.curtismeyer.com/">http://www.curtismeyer.com/</a></div>
<div><br></div><div><br></div></div><br><br>
</div><div><div>
<br><div><div>On Jun 13, 2014, at 12:04 AM, Richard Jones <<a href="mailto:richard.t.jones@uconn.edu">richard.t.jones@uconn.edu</a>> wrote:</div><br><blockquote type="cite"><div dir="ltr">Mark and all,<div>
<br></div><div>Sequence should be:</div><div><ol><li>pion stops</li><li>if negative pion, captures on an atom, spirals in to s-shell, emitting X-rays below Geant cutoff</li><li>if positive pion, undergoes elastic collisions with nuclei</li>
<li>pion absorbs on nucleus and blasts out nucleons</li></ol><div>The time scale for this is a few ns. Which part of this is mysterious?</div><div><br></div><div>-Richard Jones</div><div><br></div></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Thu, Jun 12, 2014 at 3:24 PM, Mark Ito <<a href="mailto:marki@jlab.org">marki@jlab.org</a>> wrote:<br><blockquote class="gmail_quote">
Folks,<br>
<br>
Find the minutes below and at<br>
<a href="https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_June_11,_2014#Minutes">https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_June_11,_2014#Minutes</a><br>
.<br>
<br>
-- Mark<br>
________________________________________________<br>
<br>
GlueX Offline Meeting, June 11, 2014<br>
Minutes<br>
<br>
* CMU: Will Levine, Paul Mattione, Curtis Meyer<br>
* FSU: Aristeidis Tsaris<br>
* IU: Kei Moriya<br>
* JLab: Mark Ito (chair), David Lawrence, Simon Taylor<br>
* MIT: Justin Stevens<br>
* NU Sean Dobbs<br>
* UofR: Tegan Beattie, Zisis Papandreou<br>
<br>
Announcements<br>
<br>
* A minor-version-change release of CCDB is now available, ccdb_1.01.<br>
It incorporates David's recent change to treat row-wise<br>
one-dimensional constants sets the same as column-wise ones.<br>
* Data Challenge 2 REST file transfer from UConn to JLab is complete.<br>
All files have been archived to tape. There were issues with<br>
multi-stream transfers with the SRM, so only single stream was used<br>
throughout. The suspicion is that the problem is due to small file<br>
sizes. Transfers from Northwestern are next. The Computer Center<br>
has opened up the requisite ports.<br>
* Zisis commented on the state of the software getting-started<br>
documentation on the wiki. We all acknowledged that this is<br>
problem. In particular he pointed out that new students' progress<br>
is impeded by a lack of clear direction in installing the GlueX<br>
software. This must be advanced in priority by this group.<br>
<br>
Review of Minutes from the Last Meeting<br>
<br>
We went over the [24]minutes from the May 28th meeting.<br>
* Simon has changed the code to get the parameter for the minimum<br>
number of hits on a track candidate from a JANA configuration<br>
parameter. Formerly it was hard-wired at 6.<br>
* Curtis reminded us that we would like to have some kind track<br>
quality information, other than chi-squared, for example the number<br>
of "missing" hits, included in the REST output.<br>
<br>
Specifying Alternate Versions of Calibration Constants in JANA<br>
<br>
Mark led the group through [25]his wiki page, based on an email from<br>
Dmitry. At the last meeting Justin had asked for guidance on this<br>
subject.<br>
<br>
CCDB Schema Changes in Version 1.00<br>
<br>
We looked at another of Mark's [26]wiki pages, describing the<br>
relationship between database schema versions and software version.<br>
Again the presentation was based on an email from Dmitry.<br>
<br>
Reconstruction of EVIO Data<br>
<br>
David brought us up-to-date on the status of doing reconstruction with<br>
EVIO data derived from simulation output. See his [27]his slides for<br>
details. Topics covered:<br>
* EVIO vs. HDDM<br>
* Converting HDDM to EVIO<br>
* Translation tables<br>
* Configuration parameters for the rawevent plugin<br>
* Reading EVIO data into DANA<br>
* Configuration Parameters for the DAQ plugin<br>
* Still to do<br>
<br>
We are very close to having a functional system to go from simulated<br>
HDDM to EVIO to reconstruction. The only piece missing now is EVIO data<br>
as it will appear from the CAEN TDCs.<br>
<br>
BCAL Truth<br>
<br>
Will explained in more detail the mystery he sees in the [28]simulation<br>
output (scroll down to the attachment) that is likely responsible for a<br>
late tail in the BCAL time distributions for pions. He sees a pion<br>
interact in the BCAL and<br>
<br>
3.5 ns after the pion dies, in the exact same location as the pion<br>
death, a proton is "born". In addition to this proton, 3 other<br>
protons, 1 neutron, and 1 pion are also "born" at the exact same<br>
moment and location.<br>
<br>
We did not come up with an explanation for this. Zisis noted that the<br>
output looks like it comes from GEISHA. Irina Semenova may be able to<br>
help us with this; Zisis will ask her about it.<br>
<br>
References<br>
<br>
24.<br>
<a href="https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_May_28,_2014#Minutes">https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_May_28,_2014#Minutes</a><br>
25.<br>
<a href="https://halldweb1.jlab.org/wiki/index.php/Specifying_Alternate_Versions_of_Calibration_Constants_in_JANA">https://halldweb1.jlab.org/wiki/index.php/Specifying_Alternate_Versions_of_Calibration_Constants_in_JANA</a><br>
26.<br>
<a href="https://halldweb1.jlab.org/wiki/index.php/CCDB_Schema_Changes_in_Version_1.00">https://halldweb1.jlab.org/wiki/index.php/CCDB_Schema_Changes_in_Version_1.00</a><br>
27. <a href="https://halldweb1.jlab.org/wiki/images/d/d6/20140611_EVIO_in_DANA.pdf">https://halldweb1.jlab.org/wiki/images/d/d6/20140611_EVIO_in_DANA.pdf</a><br>
28. <a href="https://mailman.jlab.org/pipermail/halld-offline/2014-May/001681.html">https://mailman.jlab.org/pipermail/halld-offline/2014-May/001681.html</a><br>
<font color="#888888"><br>
--<br>
Mark M. Ito, Jefferson Lab, <a href="mailto:marki@jlab.org">marki@jlab.org</a>, <a href="tel:%28757%29269-5295">(757)269-5295</a><br>
<br>
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