[Halld-offline] Offline Software Meeting Minutes, April 3, 2013

[Mark M. Ito]

Find the minutes at 
https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_April_3,_2013#Minutes 
and below.
_____

GlueX Offline Meeting, April 3, 2013
Minutes

Present:
* CMU: Will Levine, Curtis Meyer, Paul Mattione
* JLab: Mark Ito (chair), Simon Taylor, Elliott Wolin, Beni Zihlmann
* Northwestern: Sean Dobbs
* IU: Matt Shepherd

Announcements

* Mark announced that we will using the ReadyTalk desktop sharing
method for these meetings in the future on a trial basis. See the
[28]instructions above.
* Elliott announced that for the online, since there is no previously
existing code base, will go with the relatively new C++ 11
standard. This standard is 100% backward compatible with legacy C++
code. We briefly discussed whether the offline system should
embrace this standard as well, though without any clear
conclusions.

RF Bunch Selection

Paul described recent work on the RF bunch selection problem. Often
ghost tracks and showers influence the selection. In some contexts he
gets the wrong bucket about 20% of the time. Accidentals can effect the
result as well. He has tried a method where a particular event topology
is requested first. Only after an event satisfies the topology
requirement is bunch selection attempted and then only using tracks and
showers that are part of the given topology. He then gets a much higher
success rate. He led us through a [29]wiki page that describes the
classes that implement these ideas.

We discussed the way the start time for tracking is done now. Each
track determines a T0 for itself independently, using either the
time-of-flight or the start counter, so there is no requirement for a
pre-defined global start time to get the tracking going.

BCAL Reconstruction Work

Will has been updating the BCAL reconstruction to accommodate the new
hit generation and smearing scheme implemented by David Lawrence. He
showed [30]two diagrams that outline the flow for both the old and new
schemes. The new scheme should give more a more realistic
representation of the hits, but also requires a time-walk correction
(as will the real data). Will also remarked on the complication of
having to accommodate the change in both the old KLOE code (the current
default), and the new reconstruction scheme from Matt Shepherd.

Development is done. What is left is to do a comparison of results
using the old and new simulated data schemes. Will will work on that.

Another Alternate BCAL Reconstruction Algorithm

Beni presented [31]results from a new algorithm for BCAL
reconstruction, independent of the two mentioned in Will's talk. He was
motivated by a desire to understand the perennial problems we have seen
with photon reconstruction and wanted to work with a reconstruction
code that he understood well. He showed a simulation with 1 GeV π^0s
thrown at 50 degrees in polar angle and results from all three
reconstruction codes. Overall, both the Matt code and the Beni do
better than KLOE. Matt's appears a bit more mature at this stage. The
KLOE code seems to be particularly bad for symmetric decays. More
studies are planned.

Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_April_3,_2013"

References

28. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_April_3,_2013#ReadyTalk_Desktop_Sharing
29. 
https://halldweb1.jlab.org/wiki/index.php/Mattione_GlueX_Analysis_Factories
30. 
https://halldweb1.jlab.org/wiki/images/7/7e/Bcal_offline_mtg_20130403.pdf
31. 
https://halldweb1.jlab.org/wiki/index.php/BCAL_reconstruction_test_with_pi0

-- 
Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295