sPHENIX is a new detector at RHIC.

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

Also available on agenda: https://indico.bnl.gov/conferenceDisplay.py?confId=1940

 

Announcement

 

Welcome to join MAPS + HF jet workfest Jan 5-7 @ Santa Fe, in which we will make next big push on tracking simulations https://indico.bnl.gov/conferenceDisplay.py?confId=2641 . Registration opened.

 

 

Repository updates

 

·       Tony and Gaku implemented ladder geometry model of silicon trackers. Working on new tracking macro so everyone could use them.

·       Chris updated HCal geometry description and preparing for next production

 

 

DCA 3D verification - Haiwang Yu

 

Summary:

·       Problem 1: bias on DCA 3D-z traced to TPC digitization. TPC group to fix it

·       Problem 2: bias on momentum and DCA2D/DCA3D_xy for high momentum tracks were traced to pattern recognition/outlier rejection stage. Carlos and Mike will work on it.

 

 

Slide 3, 4: problem on DCA 3D-z is gone after truth tracing on TPC-only and arrowed problem to TPC.

 

Slide 5: TPC cluster pull check. Phi is fine, z is biased depending on two z-halfs of TPC.

 

Mike: Correlated bias amplify the problem when fit through many TPC hits

Mike: we should consider set some INTT layer to be sensitive to z direction to help deal with such problem.

 

Ming: was TPC drift taking into account of fluctuation of drift time

Carlos: used same parameterization of spread of charge cloud.

Jin: part of the electron-to-electron drift fluctuation is taken into account when simulating the broadening of the charge cloud in the z/time dimension.

 

Slide 6: turning off this absolute propagation time, cluster pull become centered.

 

Action Item [TPC team]: fix bias of full propagation time -> drift time to relative propagation -> drift time

 

 

Slide 7: setting seed for Kalman fit with GenFit2 using the outer most cluster and 100 GeV momentum

 

Mike: what happen when simulating low momentum track? Maybe better use first and second hit as the initial vector

Action Item [Haiwang]: try both seeds out and fit a wide range of momentum

 

 

Slide 8: found a new problem that momentum and DCA_XY is biased at higher momentum.

 

Jin: DCA_z pull width is off 1?

Haiwang: after fixing TPC cluster bias, its width gets narrower

 

Slide 9-11: the problem was traced the pattern recognition prefer clusters that constitute a more bended track.

 

Mike: two possible process in pattern recognition could cause this problem:

1.       Hough pattern recognition window;

2.       Grooming process during outlier rejection

 

Action Item [Carlos, Mike]: investigate the pattern recognition bias for high momentum tracks

 

Mike: Which version of tracking macro was used to show this problem?

Haiwang: MAPS + TPC in cylindrical version.

 

 

 

______________________________

 

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, December 12, 2016 2:00 PM
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 Dec 13th, 1PM EST @ 2-219

 

Hello everyone,

 

This is a reminder for a brief sPHENIX simulation and software meeting, Tue Dec 13th, 1PM EST @ 2-219

 

Currently on agenda is continue the study of last week:

•            Merging ladder geometry for MAPS and INTT - Tony, Gaku, Haiwang.

•            3-D DCA fitting and 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=1940   , 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

______________________________