Π polarizability Meeting Sep. 14, 2012
We meet via Skype. The relevant Skype user names are:
- Rory Miskimen - rmiskimen
- Alexander Mushkarenkov - alexander_mushkarenkov
- Elton Smith - eltonssmith
- David Lawrence - aehsdad
Previous meeting: Aug. 30, 2012
- Noisy events
Attendees: Rory M., Sasha M., Elton S., David L.
- Rory and Sasha sat down to look at some events on the viewer last week while Rory was in Germany. They noticed that
a majority of the events looked very busy with lots of tracks. Very few looked to be clean π+π- events. They thought this was likely causing a lot of the problems seen in the plots Sasha showed 2 weeks ago.
- There was some question that the target geometry may be incorrect and David volunteered to look into it.
- During the discussion, it was pointed out that since all of the options were turned on for drawing, multiple lines
were being drawn for each track which may have been causing some events to look worse than they were. Sasha was going to try looking through them again with some options (like DTrackCandidate and DTrackeWireBased, etc...) turned off.
- It was also noted that in the first event Sasha showed there were several "thrown" particles even though the event was produced
using a single π+ from a particle gun. These appeared to be due to the pion decaying, but charge did not appear to be conserved so a mystery remained.
- It was noted that Rory and Sasha some some cleaner events where the secondaries were turned off. Sasha will try
re-running the simulation/reconstruction with the secondaries turned off to produce plots similar to those shown at the meeting 2 weeks ago.
- David showed two plots made from events generated using bggen. The first was of the "t" distribution and the second was
of the W distribution of both exclusive and inclusive π+π- events.
- Rory suggested a plot of the elasticity of the π+. Dave will do this in the signal regions.
- Send David control.in file and 3 single pi+ events shown at meeting (Sasha)
- Review geometry and do radiation length scan to make sure it is correct (David)
- For Pythia events, make histogram of elasticity for π+π- in W<400MeV region (David)
- Reproduce reconstruction histograms with secondaries and decays turned off (Sasha)