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[Star-hp-l] Notes for PWGC preview (5/27/2022): Event activity correlations and jet measurements in p+Au collisions at \sqrt{s_NN} = 200 GeV at STAR
- From: Rongrong Ma <marr AT rcf.rhic.bnl.gov>
- To: STAR Papers Discussion List <Starpapers-l AT lists.bnl.gov>, STAR experiment physics discussions <star-phys-l AT lists.bnl.gov>, STAR Jet-like Correlation PWG list <jetcorr-star-l AT lists.bnl.gov>, Star-hp-l AT lists.bnl.gov
- Subject: [Star-hp-l] Notes for PWGC preview (5/27/2022): Event activity correlations and jet measurements in p+Au collisions at \sqrt{s_NN} = 200 GeV at STAR
- Date: Fri, 27 May 2022 13:40:45 -0400
Date: 5/27/2022
Participants: David Stewart, Joern Putschke, Veronica Verkest, Barbara Trzeciak, Yi Yang, Sooraj Radhakrishnan, Daniel Cebra, Md Nasim, Maria Zurek, Qianghua Xu, Hanseul Oh, Raghav Kunnawalkam Elayavalli, Nihar Sahoo, Prithwish Tribedy, Subhash Singha, Jiangyong Jia, Hanna Zbroszczyk, Rongrong Ma, Takafumi Niida
Title: Event activity correlations and jet measurements in p+Au collisions at \sqrt{s_NN} = 200 GeV at STAR
PAs: Helen Caines, Joern Putschke, David Stewart, Veronica Verkest
Target journal: PRC
Proposal page: https://drupal.star.bnl.gov/STAR/blog/djs232/Paper-EA-and-UE-Corrs-High-Q2-Events-pAu-sNN200-GeV-Collisions-STAR
The PWGC panel previewed a paper from JetCorr PWG. The panel found that analysis is mature and the paper should move forward, and the target journal is appropriate. The following points were discussed.
(Q: question, A: answer, C: comment)
Q; Are systematic uncertainties included in the figures?
A: For Fig. 2, these uncertainties will be re-evaluated, and expected to be reduced significantly. Figures 3 and 5 are fully corrected with uncertainties estimated. We do not expect to assign uncertainties to Fig. 4, and for Figs. 6 and 7 uncertainties need to be added.
A: For Fig. 2, these uncertainties will be re-evaluated, and expected to be reduced significantly. Figures 3 and 5 are fully corrected with uncertainties estimated. We do not expect to assign uncertainties to Fig. 4, and for Figs. 6 and 7 uncertainties need to be added.
Figure 3
Q: How is pileup corrected?
A: We plotted track multiplicity vs. ZDCx and parametrized pileup contribution based on intercept at ZDCx = 0.
Q: But the tracking efficiency also depends on ZDCx?
A: We will look into that
C: Whenever one wants to select events based on TPC multiplicity, one needs to take into account pileup and tracking efficiency, both of which depend on luminosity.
Q: How is pileup corrected?
A: We plotted track multiplicity vs. ZDCx and parametrized pileup contribution based on intercept at ZDCx = 0.
Q: But the tracking efficiency also depends on ZDCx?
A: We will look into that
C: Whenever one wants to select events based on TPC multiplicity, one needs to take into account pileup and tracking efficiency, both of which depend on luminosity.
Figure 6
Q: How are these distributions normalized? How do you deal with three-jet events? What is the probability to have more than one pair of jets per event? Are there any differences in dphi resolutions between low and high EA?
A: These distributions are self-normalized by number of jet pairs entering the distributions. Our code only accepts one jet pair per event. At 200 GeV, the probability to have multiple jet pairs satisfying our selection cuts is extremely rare. We will provide numbers. Given that these are pAu events, we do not expect any significant differences in TPC performance between low and high EA.
Q: How do you deal with the different UE contributions to jet pt for low and high EA?
A: This has not been done yet. Our plan is to increase the UE contribution by hand in low EA events to match that of high EA events, for a fair comparison. Simulations have shown comparable JES and JER between low and high EA events.
Q: How are these distributions normalized? How do you deal with three-jet events? What is the probability to have more than one pair of jets per event? Are there any differences in dphi resolutions between low and high EA?
A: These distributions are self-normalized by number of jet pairs entering the distributions. Our code only accepts one jet pair per event. At 200 GeV, the probability to have multiple jet pairs satisfying our selection cuts is extremely rare. We will provide numbers. Given that these are pAu events, we do not expect any significant differences in TPC performance between low and high EA.
Q: How do you deal with the different UE contributions to jet pt for low and high EA?
A: This has not been done yet. Our plan is to increase the UE contribution by hand in low EA events to match that of high EA events, for a fair comparison. Simulations have shown comparable JES and JER between low and high EA events.
Q: Could you check the ZDCx distributions for low and high EA events to make sure TPC performances are comparable?
A: Will provide plots.
Q: Could you make the upper panel log-scale?
A: Yes, will do.
A: Will provide plots.
Q: Could you make the upper panel log-scale?
A: Yes, will do.
Figure 7
Q: What is the influence of three-jet events?
A: Three-jet events are very rare at 200 GeV. Will check and provide numbers. On the other hand, an ALICE paper did cite three-jet events as a possible explanation for some bias seen in pp collisions at the LHC.
Q: What is the influence of three-jet events?
A: Three-jet events are very rare at 200 GeV. Will check and provide numbers. On the other hand, an ALICE paper did cite three-jet events as a possible explanation for some bias seen in pp collisions at the LHC.
Conclusions
C: Only a few interactions are needed to produce collective phenomenon. It is not clear that the absence of jet quenching implies correlation at initial stages.
A: While it is true that a few final-state interactions can produce collectivity, the measured correlation between TPC and BBC, with a rapidity gap of 5 units, have to come from initial stages by causality argument.
C: Only a few interactions are needed to produce collective phenomenon. It is not clear that the absence of jet quenching implies correlation at initial stages.
A: While it is true that a few final-state interactions can produce collectivity, the measured correlation between TPC and BBC, with a rapidity gap of 5 units, have to come from initial stages by causality argument.
Q: Can one compare these results to PYTHIA, which might strength the physics message?
A: We will look into that, but defining EA in PYTHIA and making it comparable to data are not trivial.
C: It could be easier to compare based on TPC EA, not BBC EA.
A: We will look into that, but defining EA in PYTHIA and making it comparable to data are not trivial.
C: It could be easier to compare based on TPC EA, not BBC EA.
- [Star-hp-l] Notes for PWGC preview (5/27/2022): Event activity correlations and jet measurements in p+Au collisions at \sqrt{s_NN} = 200 GeV at STAR, Rongrong Ma, 05/27/2022
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