sPHENIX discussion of physics

[Anthony Frawley <afrawley AT fsu.edu>]

Here are the notes from yesterday's HF/Q meeting.

Tony

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Zhaozhang Shi: Ks analysis in STAR and sPHENIX

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Results of Ks reconstruction study in STAR, and early results in sPHENIX simulations.

Tony: (slide 22) the Ks mass resolution in sPHENIX should be 4 MeV/c^2. Maybe finer histogram binning?

Joe: Are these MVTX matched tracks only?

No, no selection is made. Have to add silicon association to KFParticle.

Jin: TPC only tracks will have poorer DCA resolution, so more likely to be rejected.

Xuan: What is the particle multiplicity in an average event?

Cameron: The number of reconstructed tracks is saved in the KFP ntuple.

Zhaozhong was not able to get the truth info working in the sPHENIX study, so will not have efficiency study until that is fixed.

Joe Osborn: Tests of tracking with event-by-event distortions included but not corrected

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Event-by-event distortions are now simulated to be ~ 50-100 microns.

-- Can we do physics with data without event-by-event distortion corrections?

Tracking works, DCA resolution OK, pT resolution worse by ~ x 2.

Could not do Upsilons, some physics topics OK.

Jin: Can we make this setup generally available?

Joe: Yes, the flags for turning it on are already in place in the macros.

     Joe will post some pointers in reply to these minutes.

Christof Roland: DST layout for analysis of tracking results

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Format of reconstruction output is tracking expert task.

Format of Analysis μDST TTrees needs to be defined. This is a topical group task.

Discussion:

Going from Job C of the tracking reconstruction to analysis needs a layer in between.

Different topics will require different tree structures - very analysis dependent.

We need to start on Tree structures as soon as possible, iterations will be needed.

Would be best to stay below ~ 100 TB for analysis μDST's.

Christof: You can get a large reduction in storage by trading off between convenience and efficiency. For example using floats is convenient, but float precision is not usually needed.

Slide 3: The 4-vector in the μDST needs uncertainties for secondary vertex calculation.

Cameron: could avoid using the full covariance by calculating and storing the secondary vertices with the 4-vectors.

Jin: Cannot calculate the secondary vertex for all users at once. But do we need the full covariance? Diagonal elements enough?

Joe: How do the timescales change for the first (commissioning) run?

Christof: Should not detach this run from future runs. We will iterate frequently in the first run, but we have to keep our eye on the long term.

Tony: We should request a strawman for every analysis topic. Maybe discuss this in the TG meeting the week after the workfest?

-- It was agreed that we should have some kickoff discussions during the workfest.

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From: Anthony Frawley <afrawley AT fsu.edu>
Sent: Wednesday, March 1, 2023 2:23 PM
To: sPHENIX-HF-jets-l <sphenix-hf-jets-l-bounces AT lists.bnl.gov>; Sphenix-upsilons-l AT lists.bnl.gov <Sphenix-upsilons-l AT lists.bnl.gov>; sphenix-physics-l AT lists.bnl.gov <sphenix-physics-l AT lists.bnl.gov>; Anthony Frawley <afrawley AT fsu.edu>
Subject: Re: [Sphenix-upsilons-l] HF/Q topical group meeting tomorrow, March 2 at 11:30 am ET

 

Sorry, the meeting starts at 11:30 am, not 11 am. That was a typo.

Tony

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From: sPHENIX-upsilons-l <sphenix-upsilons-l-bounces AT lists.bnl.gov> on behalf of Anthony Frawley via sPHENIX-upsilons-l <sphenix-upsilons-l AT lists.bnl.gov>
Sent: Wednesday, March 1, 2023 2:02 PM
To: sPHENIX-HF-jets-l <sphenix-hf-jets-l-bounces AT lists.bnl.gov>; Sphenix-upsilons-l AT lists.bnl.gov <Sphenix-upsilons-l AT lists.bnl.gov>; sphenix-physics-l AT lists.bnl.gov <sphenix-physics-l AT lists.bnl.gov>
Subject: [Sphenix-upsilons-l] HF/Q topical group meeting tomorrow, March 2 at 11:30 am ET

 

Hi All,

We will have our HF/Q topical group meeting tomorrow, March 2, at 11 am ET. The indico and zoom links are:

https://indico.bnl.gov/event/18537/

https://bnl.zoomgov.com/j/1613938007?pwd=QjYzUnpYQ2xNZWZLSy9qd3Z4dFpzZz09

We have the following talks on the agenda:

• Introduction: Conveners
  
• Data Compression: Christof Roland
  
• Ks reconstruction in STAR: Zhaozhong Shi
  
• Tracking with distortions: Joe Osborn
  

Best regards

Cameron, Jin, Tony and Marzia