STAR HardProbes PWG

[Barbara Trzeciak <barbara.trzeciak AT gmail.com>]

Date: 01/10/2025

Participants: Yang He, Maowu Nie, Rongrong Ma, Mathias Labonte, Guannan Xie, Hanna Zbroszczyk, Jae Nam, Nihar Sahoo, Prithwish Tribedy, Qian Yang, Richard Seto, Ting Lin, Xiaoxuan Chu, Yue Hang Leung, ShinIchi Esumi, Sooraj Radhakrishnan, Barbara Trzeciak

Title: Semi-inclusive hadron+jet measurement in Ru+Ru and Zr+Zr collisions at 200 GeV in STAR

PAs: Yang He, Rongrong Ma, Maowu Nie, Nihar Sahoo, Li Yi

Target journal: Physics Letters B

Proposal page: https://drupal.star.bnl.gov/STAR/blog/nie/Paper-proposal-Semi-inclusive-hadronjet-measurement-RuRu-and-ZrZr-collisions-200-GeV-STAR

Presentation: https://drupal.star.bnl.gov/STAR/system/files/20250110_PWGC_preview.pdf

The PWGC panel previewed a paper proposal from HP PWG. The panel found that the analysis is mature and results are important and interesting, and the paper should move forward. The journal choice was also found to be appropriate. The following points were discussed.

Q: How do you build your response matrix, you’re not using full jet embedding?

A: No, the bkg. fluctuations are from the data and the detector part is based on PYTHIA6 and embedding for isobar data for different particle species. More details are in backup.

Q: Do you have model comparison?

A: Not yet, we’re waiting. The shown comparison is with ALICE data.

Q: Fig. 4: the ratio is below 1 for high pT, but the first low pT point is quite above 1.

A: That could be due to splitting.

Q: It would be interesting to see, at least internally, how this ratio evolves with R, i.e. look at R=0.2/R=0.3, R=0.2/R=0.4 ratios.

Q: Fig. 4: can we make a comparison to Au+Au and make a conclusion on system size dependence?

A: There should still be trigger effects there so the comparison might not be so robust. Baseline should be similar for different R, but in a higher pT range than what we measure, and the effect may depend on the system. But we can, at least internally, make a comparison. 

Q: It would be nice to find a way to compare the two systems, isobar and Au+Au, though trigger ranges are also different. 

Q:  Do we have the same LBT model prediction for Au+Au?

A:  We will check.

Q: Are you going to specify the unbiased region?

A: We specified the unbiased region earlier for inclusive jet paper.