[Halld-physics] Monday Physics Meeting

[Ryan Mitchell]

Hi,

I posted brief notes from this morning to the wiki, and also include  
them below...

Ryan


I.  Updates on Reconstruction Software:

A.  Tracking:  Simon fixed the recent crashes in the tracking code,  
which were apparently due to bad start counter timing information.   
Igor confirmed that this has fixed his problems.

B.  Calorimetry:  Will checked in tweaks to Matt's BCal algorithm.   
(Note that the KLOE algorithm is still the default algorithm.)

C.  PID:  No updates on PID, Paul is working on BCal segmentation  
studies.

II.  Ongoing Analyses

A.  b1pi (Igor):  Igor showed the results of his first fits using full  
detector acceptance and no background.  He generated two waves, and  
then used five in the fit.  There was considerable leakage into non- 
signal waves, but he also used small samples of signal MC for the  
normalization integrals.  This could, in principle, explain both the  
leakage and the apparent underestimation of the sizes of the error  
bars.  The event generator (which uses accept-reject and runs around a  
few Hertz) is currently a bottle-neck for the signal MC production.   
Importance sampling on the omega could help a lot and Igor will  
investigate.

B.  cascades (Nathan):  Nathan is still looking at tracking issues.   
One test he performed was to seed tracks with truth information.  This  
only resulted in minor improvements in efficiencies.  Another test was  
to look at the difference between track efficiencies when the track is  
isolated (i.e. produced using a particle gun with the same kinematic  
distributions) and when the track is embedded in a full event.  When  
isolated his pi- has an efficiency ~30%, but in a full event the same  
pi- has efficiency ~10%.  So the background associated with additional  
curling tracks has a large effect on efficiency.

III.  Mass MC Production and Storage

Richard may be able to give an update in two weeks.  There is  
currently 60TB of pythia MC on the grid (in the older uncompressed  
format).



On Nov 6, 2011, at 10:43 PM, Ryan Mitchell wrote:

> Hi,
>
> This is a reminder that we'll have a GlueX physics meeting tomorrow  
> morning at 11:30AM, as usual.  I uploaded an agenda to the wiki.  So  
> far I've had no special requests, so by default we will just check  
> on the status of various projects.  Feel free, though, of course, to  
> upload additional material.
>
> Ryan
>
>