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=1926

 

 

Electron ID and Upsilon background - Sasha Lebedev

 

Summary: electron ID performance and Upsilon + background projection in AuAu

 

Electron ID

 

Slide 2: In anti-proton, did not observe much difference in inner Hcal energy.

Jin (post meeting comment): last simulation showed x2 improvement by using inner HCal on top of E/p cuts for single anti-proton simulation @ 2-4GeV/c in p. Expect less effect in HIJING embedded events due to background fluctuation in the inner HCal.

 

Slide 3: observed different rejection for proton and kaons when compared to pions.  

Jin: expect some difference from hadron interaction cross section that is different for pi/K/pi and their anti-particles.

 

Slide 5: tradeoff between efficiency and background rejection.

Jin: In the past two weeks, further option of MAPS + IT + TPC are also available now for simulation study: https://github.com/sPHENIX-Collaboration/macros/pull/35

 

Gabor: was electron efficiency curve used inner HCal information?

Sasha: with E/p only. Page 2 suggest inner HCal do not help much after EMCal E/p cut in central HIJING events.

 

Jin: was the E/p cut are single-side cuts

Sasha: Yes. only applying on the lower side cut for the E/p.

 

Upsilon background estimation

 

General documentation:

·       Please upload analysis software to the analysis repository on GitHub (write permission to everyone in collaboration):  https://github.com/sPHENIX-Collaboration/analysis . Suggest make a sub folder e.g. Upsilon-analysis

·       Analysis note -> wiki. Need write permission account to edit wiki. Please contact John Haggerty for establishing the account.

  

Slide 5:

Ming: For DY in lower mass region, Pythia differ from NLO pQCD by x3 times is surprising

Sasha: tune has not been changed for three years. Current tune focus on the Upsilon mass region that fits well with pQCD. Details in write-up.

Sasha/Marzia: agree that it is important to revise Pythia settings

 

Slide 6:

Jin: could be useful to double check hadron spectrum as published in Phys. Rev. C 88, 024906 (2013) that extend the hadron spectrum in pp and AUAU to higher pT

 

Slide 11: Upsilon generator contains y and pT dependence

 

Slide 12: final Upsilon line shape with background estimation

 

Jin: one useful performance benchmark could be Upsilon R_AA statistical error bar projection, extracted from fitting on the invariant mass spectrum  

 

Jin: how large is the photon conversion background.

Sasha: previous study show a small effect due to the conversion electrons are shifted to significantly softer pT when compared with hadrons. Will find the older study material.

 

John Haggerty: we should update the Delta R_AA projection plot.

 

 

b-tagging with displaced vertex - Sanghoon

 

Summary: updated plot for performance for tracking review.

Plan: look at invariant mass and pT distribution of the secondary vertex. Improve documentation.

 

 

b-tagging with track counting - Haiwang

 

Summary: Recalculate DCA to allow choose 2D (default) or 3D DCAs. 3D DCA performance previewed.

Plan:  Improve sigmalization for 3D-DCA; HIJING embedding; convert to Likelihood analysis.

  

Slide 4: performance curve match exactly between default DCA2D variable and new DCA2D calculated in analysis module. Sanity check before moving to 3D-DCA calculation in the analysis module

 

Slide 5:

DCA-3D purity using 2D sigma estimation, which further improves over the 2D DCA curve.

 

Ming: in simulation, are you using the reconstructed vertex?

Haiwang: Yes.

Ming: what was the vertex resolution?

Haiwang: ~10um in sigma_x and sigma_y with an average multiplicity of 15 tracks per collision after a reconstructed pT cut of 0.5 GeV/c (high-pT jetty events in p+p collision @ sqrt(S) = 200 GeV)

 

 

Tracking performance VS centrality - Sourav

 

Summary: study of tracking performance with embedding in three different centrality categories.

 

Slide 2-3: performance with loose-matching cut for MAPS + TPC

 

Dave: why efficiency drops for MAPS+TPC @ high pT? Expect stay high efficiency at high pT

Sourav: Not yet understood. Such drop not observed with IT.

Dave: what was the requirement on hit on the silicon detectors?

Sourav: require correct MAPS hit and IT hits matched to the reconstructed track. Then allow missing 27 of 60 max possible TPC clusters.

Jin: suggest check the population of failed tracks and check how they failed in term of matching: association or quality cuts or pT matching cut. In the case of pT matching cut, please plot the dpT spectrum.

 

Haiwang: which analysis tool was used to perform such analysis?

Sourav: Mike’s standard tracking evaluator.

 

Slide 4-5: performance with tight-matching cut for MAPS + TPC

Sourav: requirement is 3/3 in MAPS, 4/4 in IT and 57/60 TPC hits

 

 

______________________________

 

Jin HUANG

 

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________

 

From: Huang, Jin
Sent: Tuesday, September 6, 2016 8:17 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 Sept 6th, 1PM EST @ 2-219

 

Hello everyone,

 

This is a reminder for a regular sPHENIX simulation and software meeting, Tue Sept 6th, 1PM EST @ 2-219.

 

Currently on agenda are:

·       Upsilon background simulation

·       B-tagging with secondary vertex

·       B-tagging with displaced vertex

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=1926  , for which the common modification password is "1008"

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

•            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

 

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________