sPHENIX is a new detector at RHIC.

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

Also available on agenda page: https://indico.bnl.gov/conferenceDisplay.py?confId=1935

 

 

Upsilon projection update - Sasha Lebedev

 

Slide 2: updated RAA projection code now produce consistent uncertainty in RAA with the sPHENIX proposal if using the same e-ID assumption.

Tony: how Upsilon counts and RAA calculated?

Sasha: see page 6.

 

Slide 5: worse uncertainty observed on Upsilon 3S, which traced to only 26 3S is found in the integrated pT window after realistic suppression.

 

Slide 6: updated invariant mass spectrum

 

Jin: Comparing to sPHENIX proposal Fig 4.45 invariant mass spectrum, is the correlated background much higher comparing to the Upsilon 3S count?

Sasha: the difference may come from the pT dependence

Jin: Since the ratio between the correlated background and   correlated background in pp

Tony: in principal yes.

Jin: Just realized one major reason for the high ratio for correlated background/Upsilon 3D on slide 6 is that slide 6 included RAA suppression, while the sPHENIX proposal Fig 4.45 is the baseline line shape with RAA = 1. In this case, the p+p correlated background will be small in the new projection too.  

 

 

Discussion:

 

Sasha: trying to determine how to best extract RAA using a line-shape fit.

Tony: one option is to fix the pT and centrality dependence of line shape and only fit amplitude constant for each pT bin. The line shape dependence goes to systematic uncertainty

Tony: expect offline discussion on line shape fit between Tony and Sasha

 

 

Plan:

Tony/Marzia: for the new projection, plan to also revisit on Upsilon yield and tracking efficiency, beside Sasha’s pT-dependent electron-ID studies

John H.: on time scale of CD-1/June, such projection will be needed for CDR.

 

 

Investigating momentum/DCA reconstruction - Haiwang Yu

 

Slide 3: problem that understudy, biased central value observed on the pull distribution.

 

Slide 4-5: biased TPC cluster pull distribution was traced to space charge residual distortion introduced earlier.

 

Slide 6: however, after removing space charge distortion and correcting for the radial shift of TPC clusters, the high pT track still get reconstructed with averagely about 2% lower p_T than truth using GenFit2.

Jin: Event so, GenFit2 is still much improved with the default reconstruction software. Suggest further test with perfect pattern recognition but with realistic Kalman filter. If cannot trace down the true cause, we can consider use recalibrator to correct back as in the past.  

 

Jin: plan is the refine GenFit2 result to use in b-tagging. Suggest now to put higher priority on solving the narrowed DCA pull distribution.

 

Chris: what is the source for cluster pull width dependence on radius

Haiwang: checked to be good clusters

Jin: suggest use zero magnetic field simulation to eliminate the possible origin due to track bending that leads to arbitrarily wider cluster in the bending direction (azimuth).   

 

 

Chris: it took some time to trace down the TPC cluster deviation to the known space charge distortion put in earlier. Again emphasizing the need of a QA history to help trace down changes in the software.

Action Item [volunteer needed]: helping building a QA history in the nightly builds

 

 

 

______________________________

 

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 7, 2016 10:20 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 8th, 1PM EST @ 2-219

 

Hello everyone,

 

This is a reminder for a regular sPHENIX simulation and software meeting, Tue Nov 8th, 1PM EST @ 2-219

 

Currently on agenda are continuing investigations on the following topics:

•            Upsilon R_AA projection update - Sasha Lebedev

•            Track fit and MAPS/TPC cluster quality checks - 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=1935  , 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

______________________________