[Halld-offline] Fwd: Offline Software Meeting Minutes, June 11, 2014
Richard Jones
richard.t.jones at uconn.edu
Fri Jun 13 08:50:24 EDT 2014
Curtis,
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.
1. http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/StrauchDiss.pdf
2.
http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/PhysRevA.45.6202.pdf
3.
http://gryphn.phys.uconn.edu/halld/hdgeant/pionabs/paper_1402630812.pdf
-Richard Jones
On Fri, Jun 13, 2014 at 6:14 AM, Curtis A. Meyer <cmeyer at cmu.edu> wrote:
> Hi Richard -
>
> From my p-bar days, I would have thought the time scales were sub-ns on
> these processes.
> Will sees them from ~ns to perhaps 10-15 ns.
>
> Curtis
> -------
> Prof. Curtis A. Meyer Department of Physics
> Phone: (412) 268-2745 Carnegie Mellon University
> Fax: (412) 681-0648 Pittsburgh, PA 15213
> curtis.meyer at cmu.edu http://www.curtismeyer.com/
>
>
>
>
>
> On Jun 13, 2014, at 12:04 AM, Richard Jones <richard.t.jones at uconn.edu>
> wrote:
>
> Mark and all,
>
> Sequence should be:
>
> 1. pion stops
> 2. if negative pion, captures on an atom, spirals in to s-shell,
> emitting X-rays below Geant cutoff
> 3. if positive pion, undergoes elastic collisions with nuclei
> 4. pion absorbs on nucleus and blasts out nucleons
>
> The time scale for this is a few ns. Which part of this is mysterious?
>
> -Richard Jones
>
>
>
> On Thu, Jun 12, 2014 at 3:24 PM, Mark Ito <marki at jlab.org> wrote:
>
>> Folks,
>>
>> Find the minutes below and at
>>
>> https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_June_11,_2014#Minutes
>> .
>>
>> -- Mark
>> ________________________________________________
>>
>> GlueX Offline Meeting, June 11, 2014
>> Minutes
>>
>> * CMU: Will Levine, Paul Mattione, Curtis Meyer
>> * FSU: Aristeidis Tsaris
>> * IU: Kei Moriya
>> * JLab: Mark Ito (chair), David Lawrence, Simon Taylor
>> * MIT: Justin Stevens
>> * NU Sean Dobbs
>> * UofR: Tegan Beattie, Zisis Papandreou
>>
>> Announcements
>>
>> * A minor-version-change release of CCDB is now available,
>> ccdb_1.01.
>> It incorporates David's recent change to treat row-wise
>> one-dimensional constants sets the same as column-wise ones.
>> * Data Challenge 2 REST file transfer from UConn to JLab is
>> complete.
>> All files have been archived to tape. There were issues with
>> multi-stream transfers with the SRM, so only single stream was
>> used
>> throughout. The suspicion is that the problem is due to small file
>> sizes. Transfers from Northwestern are next. The Computer Center
>> has opened up the requisite ports.
>> * Zisis commented on the state of the software getting-started
>> documentation on the wiki. We all acknowledged that this is
>> problem. In particular he pointed out that new students' progress
>> is impeded by a lack of clear direction in installing the GlueX
>> software. This must be advanced in priority by this group.
>>
>> Review of Minutes from the Last Meeting
>>
>> We went over the [24]minutes from the May 28th meeting.
>> * Simon has changed the code to get the parameter for the minimum
>> number of hits on a track candidate from a JANA configuration
>> parameter. Formerly it was hard-wired at 6.
>> * Curtis reminded us that we would like to have some kind track
>> quality information, other than chi-squared, for example the
>> number
>> of "missing" hits, included in the REST output.
>>
>> Specifying Alternate Versions of Calibration Constants in JANA
>>
>> Mark led the group through [25]his wiki page, based on an email from
>> Dmitry. At the last meeting Justin had asked for guidance on this
>> subject.
>>
>> CCDB Schema Changes in Version 1.00
>>
>> We looked at another of Mark's [26]wiki pages, describing the
>> relationship between database schema versions and software version.
>> Again the presentation was based on an email from Dmitry.
>>
>> Reconstruction of EVIO Data
>>
>> David brought us up-to-date on the status of doing reconstruction with
>> EVIO data derived from simulation output. See his [27]his slides for
>> details. Topics covered:
>> * EVIO vs. HDDM
>> * Converting HDDM to EVIO
>> * Translation tables
>> * Configuration parameters for the rawevent plugin
>> * Reading EVIO data into DANA
>> * Configuration Parameters for the DAQ plugin
>> * Still to do
>>
>> We are very close to having a functional system to go from simulated
>> HDDM to EVIO to reconstruction. The only piece missing now is EVIO
>> data
>> as it will appear from the CAEN TDCs.
>>
>> BCAL Truth
>>
>> Will explained in more detail the mystery he sees in the
>> [28]simulation
>> output (scroll down to the attachment) that is likely responsible for
>> a
>> late tail in the BCAL time distributions for pions. He sees a pion
>> interact in the BCAL and
>>
>> 3.5 ns after the pion dies, in the exact same location as the pion
>> death, a proton is "born". In addition to this proton, 3 other
>> protons, 1 neutron, and 1 pion are also "born" at the exact same
>> moment and location.
>>
>> We did not come up with an explanation for this. Zisis noted that the
>> output looks like it comes from GEISHA. Irina Semenova may be able to
>> help us with this; Zisis will ask her about it.
>>
>> References
>>
>> 24.
>>
>> https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_May_28,_2014#Minutes
>> 25.
>>
>> https://halldweb1.jlab.org/wiki/index.php/Specifying_Alternate_Versions_of_Calibration_Constants_in_JANA
>> 26.
>>
>> https://halldweb1.jlab.org/wiki/index.php/CCDB_Schema_Changes_in_Version_1.00
>> 27.
>> https://halldweb1.jlab.org/wiki/images/d/d6/20140611_EVIO_in_DANA.pdf
>> 28.
>> https://mailman.jlab.org/pipermail/halld-offline/2014-May/001681.html
>>
>> --
>> Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295
>>
>> _______________________________________________
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