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October 11, 2004 simulation meeting
minutes
Bill
Lockman
- Core issues:
- Douglas Smith reported
that BgsApp in release 15.8.x is producing nuclear fragments which are
not recognized by PDT. This is presumably a result of the new Bertini
Cascade model which will replace the low energy parameterized model
(Gheisha) in SP7. The job failure rate is significant (10%).
- Generators:
- Abi Soffer reported that there has been a lot of
activity
in
the AWG groups on updating particle branching fraction decay modes for
SP7. More details will be presented at the PAC AWG meeting this
Wednesday. There has also been an effort to improve the description of
resonance lineshape parameters, especially in phase space limited decay
chains, such as tau decays to A1. Dave Williams mentioned that the phi
lineshape in the simulation disagrees with experiment.
- There is
also an effort to use Pythia's two photon scattering generator in BaBar.
- Brian Petersen reported that Jetset and G4DataK
have been
updated to simulate the production of excited charmed baryon states,
but the code is not in a release yet.
- Subsystems:
- PEP/MDI/Backgrounds: PepBkgMon
ntuple has been updated to include IFR quantities. The DCH
information
needs to
be updated to include timing information. PepBkgXtcApp and PepBkgMCApp
(stripped down versions of ElfUserXtcApp and Moose, respectively) link
but need TCL scripts to run. ntuple production on the beam background
characterization data. Overlaps in the Q1 region have been removed, but
the database constants still need to be updated.
- Still waiting on the 10K / 10K samples of HER/LER
TURTLE rays.
- SVT: Bill and Alberto Cervelli have been working
on
improving the description of the upilex inside the tracking volume
(BgsSvtExtendedFullModel). This would be followed by the inclusion of
the matching cards and white cables.
- DCH: no report
- DRC: Dave Aston posted
a set of plots
from Matt Weaver, showing the trigger time distribution and the time
dependence of the DIRC PMT hits relative to the PEP-II phase clock for
cyclic trigger events acquired in runs 46643-46645 (March, 2004).
The lower right
hand plot shows the DIRC timing for events produced in the abort gap,
where there are no e+e- collisions. There is a fall-off of event hits
with a time constant on the order of 100 nanosec.There also appears to
be a constant (in time) level of background hits which could be due to
thermal neutrons. The min-train bunch structure is also
visible outside the abort gap. It would be good to get these timing
variables into the PepBkgMon ntuple.
- EMC: sp7 improvement prospects (Roberto S &
Roger B -
TBC): To understand the discrepancy between data and Monte Carlo shower
shapes, Roberto Sacco studied the effect
varying the range parameter
on the distributions of reconstructed EMC quantities. The range
parameter determines the transition between continuous and
continuous+discrete energy loss. By design, there is almost no
dependence on this parameter seen in the reconstructed EMC quantities.
Roberto will look into
the EMC material description, in particular, the description of the
material between the crystals. Dave Williams suggested that initially,
only showers which are well-contained in the EMC, e.g., those produced
by particles scattering at 90 degrees w.r.t. beam direction, should be
examined in the data Monte Carlo comparison.
- IFR: no report
- Trigger upgrade status: no report.
- AOB: Next meeting, October 25, 2004. This meeting
should focus
on SP7 readiness.
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