sPHENIX discussion of software

["Huang, Jin" <jhuang AT bnl.gov>]

Minutes also available on agenda: https://indico.bnl.gov/conferenceDisplay.py?confId=1937

 

3-D DCA for b-jet tagging - Haiwang Yu

  

Slide 2: an earlier naïve calculation of 3D DCA show improved b-jet tagging performance than the default 2-D version

 

Slide 3: proposing two sets of new variables to describe the two components of 3-D DCA

Haiwang: pull request will come after using proper cluster errors matrix in GenFit2

 

Slide 4: the choice of the direction vectors defining the two components of DCA vectors.

Jin: suggest check which choices of DCA vector direction produces the least correlation between vertex the five variables (DCA_XY, DCA_Z, track direction, and momentum).

 

Slide 5: some pT-dependent narrowing was observed on DCA_XY and DCA_Z pull distribution

Chris: use Geantino to isolate cluster error VS multiple scattering problem

Jin: did you see this in the DCA2D pull distribution?

Haiwang: Yes

Jin: Did you used consistent particle mass in both simulation and Kalman fit stages

Haiwang: no. Simulation used muons and reconstructed with pion mass assumption, which could cause problem in multiple scattering estimation and deviation in the width of pull distribution.

Jin: It will be useful to allow users to run multiple Kalman filter modules, pick the desired mass assumption and save to different node for analysis. It will be important for PID based analysis, such as D^0 -> pi K

 

Slide 6: also updating Kalman filter to handle exceptions without crashing

Sanghoon: the request of fix is not urgent.

Jin: the RAVE vertex fitter would also be affected by the none-ideal width of the DCA pull distribution, which affects error estimation and capabilities to reject outlier tracks.

 

Plan: try to use a separate pull request to introduce these fixes.  

 

 

Adjusting ID bit assignment for PHG4Hits  - Chris Pinkenburg

 

Preparing adjusting the 64 ID bit assignment on PHG4Hit (PHG4HitDefs::keytype). Currently it is partitioned for 8-bit for subsystem ID and 56-bit for hit ID. Suggest expanding subsystem ID to 16 bits in order to efficiently group hits that originate from the same HCal tiles. The change will be break backward compatibility with previous simulation production, which will be refreshed after the changes.

 

Please send suggestion to Chris if more subsystem bits are needed for other subsystems.

 

 

 

______________________________

 

Jin HUANG, Ph. D.

 

Associate Physicist

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________

 

From: Huang, Jin
Sent: Monday, November 21, 2016 11:43 AM
To: 'sphenix-software-l AT lists.bnl.gov' <sphenix-software-l AT lists.bnl.gov>; 'sphenix-l AT lists.bnl.gov' <sphenix-l AT lists.bnl.gov>
Subject: [reminder] sPHENIX simulation and software meeting, Tue Nov 22nd, 1PM EST @ 2-219

 

Hello everyone,

 

This is a reminder for a brief sPHENIX simulation and software meeting, Tue Nov 22nd, 1PM EST @ 2-219

 

Currently on agenda is:

•            3-D DCA fitting with aim of b-jet tagging  - Haiwang Yu

Please let us know if you have further topics to be presented at this meeting.  

 

The agenda page is at https://indico.bnl.gov/conferenceDisplay.py?confId=1937  , for which the common modification password is "1008"

•            For residents at BNL, we will meet at the 2-219 conference room

•            To join the Meeting via phone bridge:  https://bluejeans.com/619960505 

•            To join via Phone:

1) Dial:

        +1.408.740.7256

        +1.888.240.2560(US Toll Free)

        +1.408.317.9253(Alternate number)

        (see all numbers - http://bluejeans.com/numbers)

2) Enter Conference ID: 619960505

 

Cheers,

 

Jin

 

 

______________________________

 

Jin HUANG, Ph. D.

 

Associate Physicist

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________