[Halld-offline] Minutes, GlueX Offline Software Meeting, September 21, 2011

[Mark M. Ito]

People,

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_September_21%2C_2011#Minutes 
and below.

-- Mark
_____

GlueX Offline Meeting, September 21, 2011
Minutes

Present:
* CMU: Will Levine, Paul Mattione, Curtis Meyer
* IU: Ryan Mitchell, Kei Moriya, Matt Shepherd
* JLab: Hovanes Egiyan, Mark Ito (chair), David Lawrence, Yi Qiang,
Dmitry Romanov, Elton Smith, Sascha Somov, Simon Taylor, Elliott
Wolin
* Regina: Andrei Semenov
* FSU: Nathan Sparks


Announcements

* Mark announced that, by default, we will not be using the phone
anymore at these meetings. If someone does happen to have a need
for a phone connection, just let Mark know in advance.
* Elliott announced that he and David will be attending the CLAS12
Service Oriented Architecture Workshop. Contact Elliott for more
information.


Reconstruction sub-group reports


Calorimetry

Matt gave the report.
* switch from 3-3-4 segmentation to 1-2-3-4 segmentation
+ geometry specification not as flexible as originally thought
+ Will is working on it
* timing offsets
+ talking to Mihajlo: time is set by time of highest energy
block
+ x,y,z is not taken into account
+ will take some work and attention: Matt will work on this


Tracking

Simon gave the report.
* some problems have to do with the quality of track candidates
+ found issues with starting angle guess for very forward going
tracks
+ fixed up angle in track candidate
* some other minor changes
* farming out fiducial cut study a possible issue
+ note: design goal for forward direction: down to one degree


PID

Paul gave the report.
* revised PID scheme: see [44]his slides
+ original slides presented at last Physics meeting
+ changes based on feedback received on email list
+ referred us to the slides for details
* Beni: HERMES scheme used log of prob ratios
+ Beni will send around description of the scheme
* idea: instead of adding chi-squared's, try to weight chi-squared
from different sources
+ the way to do that is not clear
+ errors may be correlated
+ motivation: what if a single hit on a track if spurious: isn't
that an out-sized effect on the sum of chi-squared's?
+ some skepticism expressed about validity of this concern
* update on uncertainties
+ see [45]his wiki page for details
+ showed plots of measured uncertainties in position and energy
for the TOF as a function of both position and energy


BCAL Reconstruction Update

Will described his recent work. See [47]his wiki page for details.
* working on the new 1-2-3-4 segmentation of the BCAL
* did some studies with π^0's and resulting errors from kinematic
fitting (problem wiht phi error)
* David remarked that there is a mechanism to vary thresholds in the
code now, but that is probably not how it will be done in the end.
* Consensus was that we should retain the KLOE reconstruction scheme
as the default for now.


Plug-in to extract single particles from multi-particle events

David described a new plug-in that recasts one multi-particle into one
(or more) single particle event(s). The user selects the particle type
of interest and only that particle appears in the output event. This
allows single particle studies with spectra that match that found with
a multi-particle event generator. See [49]his slide for details.

Tracking explained

Simon gave us a summary of the method used for charged track finding
and fitting. See [51]his slides for details. In addition to describing
the process, he also showed studies of the quality of the results, and
outlined issues yet to be resolved.

Collaboration Meeting Agenda

We reviewed the proposed [53]agenda for the Offline Software session.
No objections were raised.

Retrieved from 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_September_21%2C_2011

References

44. 
http://www.jlab.org/Hall-D/software/wiki/images/1/16/Mattione_PID_Presentation.pdf
45. 
http://www.jlab.org/Hall-D/software/wiki/index.php/Mattione_Update_09212011
47. 
http://www.jlab.org/Hall-D/software/wiki/index.php/BCAL_reconstruction_9/21/11
49. 
http://www.jlab.org/Hall-D/software/wiki/images/2/29/20110921extract_ptype_hddm.pdf
51. https://halldweb1.jlab.org/talks/2011-3Q/trackingSep21_2011.pdf
53. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX-Collaboration-Sep-2011#Thursday_October_6.2C_2011