sPHENIX is a new detector at RHIC.

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

Many progress in the past week with updates related to studies in all four topical groups and the tracking group:

 

 

Software update:

 

Haiwang: https://github.com/sPHENIX-Collaboration/coresoftware/pull/239

·       Cumulated update on GenFit Kalman filter

·       Should merge soon as the related code only used by expert only

 

Martin: https://github.com/sPHENIX-Collaboration/coresoftware/pull/237

·       Online lib update to support drift chamber in FermiLab test beam facility

 

Note: unlike the coresoftware repository, the analysis repository (https://github.com/sPHENIX-Collaboration/analysis ) is directly writable to all collaborators, and no pull request is needed.

 

 

sPHENIX p+p trigger on J/Psi - Sasha Lebedev  

 

Slide 3: 3 GeV single cluster trigger leads to a J/Psi pT threshold of around 4GeV/c

·       It will be great to add trigger threshold for B meson in the B->J/Psi decay channels.

·       We can use two cluster trigger to enhance rejection of MB event while maintaining efficiency for di-electron resonances.

 

Might be important for B->J/psi R_AA measurement in the p+p baseline event triggering.

 

 

Jet angular resolution - Joe Osborn

 

Slide 4:

Jin two suggestions on recalibrating optimal phi-angle assignment for HCal towers:

1.       Correct tower’s phi in a re-calibrator while feeding it to FastJet in G4_Jet.C. Different amount correction amount for different jet total energy + jet type assumption.

2.       Or we can choose to study a set of typical jet concerned by the topical group, and correct its average \Deta\phi by default in the inner HCal geometry description (located at node RUN/TOWERGEOM_HCALIN, which requires Chris’ work).

Chris: may use two neighboring tower to further refine a particle's phi position

 

Carlos: tracker may be better in jet angular determination. Observed resolution for single track particle is on order of ~0.1mrad

Joe: not yet looked at.

Jin: we can try J. Orjuela-Koop’s flow jet analysis module: https://github.com/sPHENIX-Collaboration/analysis/blob/master/PHFlowJetMaker/PHFlowJetMaker.C . Compile and load it in the G4_jet.C and it will provide a jet node called FLOW_JETS

 

Chris: this analysis also allow us to optimize HCal design, e.g. rotate outer Hcal by half tower in the phi direction may help azimuthal resolution.

Joe/Chris: will follow offline in setting up the simulation of rotated inner-outer HCal geometry.

 

 

B-jet tagging with updated 2nd vertex tracker - Sanghoon Lim

 

Slide 2: improvement over vertex resolution by using the GenFit2+Rave vertex finder. Good pull distribution too.

 

Slide 3: refitting with updated refitting show improved performance in b-jet tagging.

Jin: what was improved on track fitting?

Sanghoon: some track missed in the refitting stage.

Jin: good to show check plot of refitting efficiency

Haiwang: better than 99.9% now after the fix

 

Haiwang: was track selected within the jet cone or using truth jet -> reco track matching?

Sanghoon: track used in 2^nd vertex finding was selected within the jet cone.

 

Slide 6:

Jin: it appears used very correlated information

Sanghoon: yes. Similar performance indicate very correlated

 

Slide 7:

Jin: it is interesting that the track pT cut is not affecting the performance in b-jet tagging in HIJING. Please try higher Jet pT cut, e.g. 1.5 and 2.0 GeV/c 

 

Coordination on b-jet HIJING production [Sanghoon and Haiwang]: coordinate two b-jet studies using single production which would perform ~0.5M HIJING embedded jetty events in about one week on ~1k condor slots. 

 

 

Tracking update with realistic ladder geometry - Tony, Gaku

 

Slide 3: cluster distribution looks nice.

 

Slide 6:

Jin: overlap will be larger from the invisible readout/support material

Tony: good to check material distribution

Chris: there is a material scan tutorial: https://wiki.bnl.gov/sPHENIX/index.php/G4commands#Some_useful_commands

Carlos: are we receiving more cluster per reconstructed track and how the clusters were counted?

Tony: only truth track association checked here. Will check reconstructed track -> cluster association.

 

Slide 7: Upsilon resolution VS number of INTT layers significantly deteriorate with four-layer INTT configuration.

Tony: hope refitting could help improving the resolution by taking account of realistic geometry in the Kalman fit stage

Tony: thickness number shown in the slides does not include overlap.

Jin: suggest check realistic overlapped mass on the cylindrical model to check optimal mass resolution with such thickness.

Haiwang: new pull request would allow using GenFit2 to handle ladder geometry in the Kalman fit.

Haiwang: Large overlap (~x2 thickness per layer?) observed in event display: https://cloud.githubusercontent.com/assets/10383186/22025975/61b8a1aa-dc9d-11e6-8ad7-d9ae4bf16db7.png

 

 

TPC software group update - Carlos

 

Slide 3:

Jin: tracking review also included reconstructed pT matching in order to match the quality of reconstructed track.

 

Slide 5:

Haiwang: now the cluster efficiency is 100% for TPC?

Carlos: Yes. Not yet considered dead channel and dead area between GEM modules.

 

Slide 11:

Jin: Good to check the source of bump in dp/p at lower side, e.g. cut on them and print out track details.

 

Slide 12:

Haiwang: dp/p is after re-calibrator.

 

Slide 13: also observed bias in DCA at high pT, the source of which was found by Haiwang to patter recognition biasing at high pT.

 

Carlos: request add cluster count in TPC/silicon tracker to the track object.

Chris: suggest that we use upper bits in cluster ID as layer number. Good to have this in the long run to allow quick recount of hit in each layer for a track object.

Action Item [Jin, Carlos]: implement this function as Chris suggested.

 

______________________________

 

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: sphenix-l-bounces AT lists.bnl.gov [mailto:sphenix-l-bounces AT lists.bnl.gov] On Behalf Of pinkenburg
Sent: Tuesday, January 17, 2017 9:08 AM
To: 'sphenix-software-l AT lists.bnl.gov' <sphenix-software-l AT lists.bnl.gov>; sphenix-l AT lists.bnl.gov
Subject: [Sphenix-l] sPHENIX simulation and software meeting, Tue Jan 17th, 1PM EST @ 2-219

 

Hello everyone,

 

This is a reminder for a regular sPHENIX simulation and software meeting,Tue Jan 17th, 1PM EST @ 2-219
We have a full agenda:
https://indico.bnl.gov/conferenceDisplay.py?confId=2676

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

See you/talk to you later

Chris

-- 

*************************************************************

Christopher H. Pinkenburg     ;    pinkenburg AT bnl.gov

                              ;    http://www.phenix.bnl.gov/~pinkenbu

Brookhaven National Laboratory       ;    phone: (631) 344-5692

Physics Department Bldg 510 C ;    fax:   (631) 344-3253

Upton, NY 11973-5000

*************************************************************