Paper Page of Measurement of Charge Correlator Ratio in pp

Title: Measurement of the charge correlator ratio in p+p collisions at STAR
PAs: Youqi Song, Helen Caines, Isaac Mooney
Target journal: PRD or PRC

Abstract: The parton-to-hadron transition, known as hadronization, is dominated by non-perturbative Quantum Chromodynamics (QCD) effects and thus challenging to study from first-principle calculations. On the other hand, experimental studies of observables sensitive to hadronization could provide valuable input. The charge correlator ratio r_c studies the charge correlation between the leading two hadrons in jets and is sensitive to hadronization effects. With data taken at sqrt{s}=200 GeV at STAR, we measure r_c in p+p collisions to probe for string-like fragmentation. These measurements, compared with various model predictions, are expected to distinguish between phenomenological model descriptions for hadronization in vacuum.

Figures: 


Fig. 1. The angular separation Delta R between the truth-level and detector-level leading (subleading) tracks in jets.

Fig. 2. Closure test that shows r_c vs jet p_T before any correction, after mistagged subtraction, and after all steps of correction. 


Fig. 3. Fully corrected r_c vs jet p_T, compared to event generator predictions. 

Conclusions: In summary, to probe for string-like fragmentation, we measure of r_c as a function of jet p_T in sqrt{s}=200 GeV p+p collisions at STAR. On average, the data show that leading charged particles in jets are more likely to be opposite signs than same sign. (In data, opposite signs occur 65% of the time and same sign 35% of the time. In PYTHIA these fractions are 68% to 32%). Compared with predictions from event generators, the fully corrected data show a weaker correlation between the leading and subleading tracks in jets. The significant difference between HERWIG and PYTHIA in their relative fractions of fragmentation vs. resonance decays might explain why their predictions for r_c are similar despite different approaches to fragmentation.

Preliminary results: page

Public presentations: 
HP 24
WWND 24
CFNS npQCD workshop
QM 23 (poster)

Presentations within STAR:
04/13/23
05/11/23
07/13/23
08/10/23
08/17/23
08/22/23: preliminary request
01/17/24
03/05/25: paper proposal
03/14/25: PWGC preview

Measurement of p-phi Correlation Functions in 200 GeV Isobar Collisions

 

Speaker : Boyang Fu


Talk time : 10:00, Duration : 00:20

FST Meeting on 02/24/2025

Start: 2025-02-25 9:00 am

 
Timezone: America/New York
 
Meeting Agenda:

update on dielectron production in Au+Au collisions at 17.3 GeV

Speaker : Ziyang Li


Talk time : 11:40, Duration : 00:20

xyc_2025_2_21

 

STAR PWGC meeting

2025-04-25 10:00
America/New York
Friday, 25 April 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00
1) Paper preview: Evidence of Spin-Interference Effects in Exclusive J/ψ→e+e Photoproduction in Ultraperipheral Heavy-Ion Collisions
     - Brief introduction from the PWG conveners (5’) [Tommy Tsang]     
     - Paper proposal (15')  [Presentation by Ashik Iqbal]
     - Open discussions (35')
     - Summary from the conveners' panel (5’)

2) Preliminaries and paper plans
      - Please ask PAs to provide drupal pages with approved Preliminary plots and preliminary request slides and add them to the PWG Preliminaries page. (Not updated since CPOD 2024?)
      - Lots of Preliminary results from STAR at HP 2024 and QM 2025. We should focus on converting them to papers. Please ask for feedback from PAs on their plans and any data/embedding production request from STAR

3) Embedding priorities  
      - LIST of embedding requests
      - outstanding requests in green (setup done) and white (setup to be done)
      - Please provide feedback on if any requests need to be prioritized, for ongoing papers/analyses in GPC/those well advanced/any upcoming conferences 
      - Will consider the priority requests for QM obselete 

4) Data production priorities 
      - Current priorities and status LINK
      - Run 23 and Run 24
      - Request to produce Run 24 p+p 200 GeV - which datasets? Is forward tracking needed?

5) Data production QA and library validations 
      - Need to set up production QA for the large datasets from Run 22 - 25
               -- Will co-ordinate with the QA board
               -- please assist the QA volunteers in doing the QA and deciding which quantities to look at
      - Validation needed for 32 bit vs 64 bit productions
               -- which datasets and observables to look at?
               -- Previous suggestions for datasets: LINK
      - ROOT6 validation, GEANT4STAR task force volunteers.
               -- Volunteers so far from ColdQCD (Anuja Khanal), LFSUPC (many volunteers, do we have a list?), HP (Tanmay Pani, Jeongmyung Kang)

6) Preliminary/preview request requirements 
      - Comparisons to existing results and other ongoing analyses from STAR

STAR PWGC meeting

2025-03-07 10:00
America/New York
Friday, 7 March 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 15:00 (GMT), duration : 00:00

STAR PWGC meeting

2025-03-14 10:00
America/New York
Friday, 14 March 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00
1) Paper preview: Measurement of the charge correlator ratio in p+p collisions at STAR
     - Brief introduction from the PWG conveners (5’) [QIan Yang]     
     - Paper proposal (15')  [Presentation by Youqi Song]
     - Open discussions (35')
     - Summary from the conveners' panel (5’)

2) QM analysis status 
      - LIST of talks and posters from STAR

STAR PWGC meeting

2025-03-21 10:00
America/New York
Friday, 21 March 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00

STAR PWGC meeting

2025-03-28 10:00
America/New York
Friday, 28 March 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00
1) QM talk/poster status 
      - LIST of talks and posters from STAR

2) Run 22 production
      - Get involved with using FWD data. PicoDsts (without tracking alignment) produced  /gpfs01/star/pwg_tasks/FwdCalib/PROD/forwardCrossSection_2022/P25ia/. Can be used for testing and developing analysis codes
      - Check picoDsts, see if all required information are there 

3) 32 bit vs 64 bit
      - Simulation study by Jason LINK
      - No major differences seen. Would like to have a physics evaluation (part of task force?)

4) GEANT4STAR task force volunteers 


STAR PWGC meeting

2025-04-04 10:00
America/New York
Friday, 4 April 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00

STAR PWGC meeting

2025-04-11 10:00
America/New York
Friday, 11 April 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00

STAR PWGC meeting

2025-04-18 10:00
America/New York
Friday, 18 April 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 14:00 (GMT), duration : 00:00

STAR PWGC meeting

2025-02-28 10:00
America/New York
Friday, 28 February 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 15:00 (GMT), duration : 00:00
1) Paper preview: Global polarization of hyperons in Au+Au collisions from the RHIC Beam Energy Scan-II
     - Brief introduction from the PWG conveners (5’) []     
     - Paper proposal (15')  [Presentation by Egor Alpatov]
     - Open discussions (35')
     - Summary from the conveners' panel (5’)

2) Embedding Status 
     - Presentation by Xianglei Zhu

3) QM Preliminary with Run21 3 GeV    
      - For analyses that we are not releasing final results, could show preliminary results with SL24a production

4) Convener Managment Meeting at CM
      - Scheduled for Thursday, March 6
      - Let us know if you have anything to bring up for discussion

STAR PWGC meeting

2025-02-21 10:00
America/New York
Friday, 21 February 2025
https://lbnl.zoom.us/j/99981267001?pwd=Q05nbjc3ZlgvR21TTzFpK2Jod2pJdz09, at 15:00 (GMT), duration : 00:00
1) Paper preview: First measurement of the spin interference dynamics of the Drell-Söding process in Au+Au 200 GeV collisions
     - Brief introduction from the PWG conveners (5’) [Yue Hang Leung]     
     - Paper proposal (15')  [Presentation by Xinbai Li]
     - Open discussions (35')
     - Summary from the conveners' panel (5’)

2) GEANT4 readiness 
     - Presentation by Jason Webb

3) QM preparation  
      - With the reduced number of nodes on SDCC, are any analyses targeted for QM severely impacted?
      - Data reproduction completed for the 4 FXT energies 
      - proton, pi+ embedding completed for 3.2 GeV. Embedding team working on other energies and requests 
 

update of K+ and K- production at sqrt{s_{NN}} = 3.5, 3.9, 4.5, 5.2, 6.2 GeV.

Speaker : Ziyue Xiang


Talk time : 11:20, Duration : 00:20

PWGC preview for DS

 

Update on Isobar Net-Proton High Moments Paper

 

Speaker : Ashish Pandav


Talk time : 16:00, Duration : 00:20

FWD Software

2025-03-05 11:00
America/New York
Wednesday, 5 March 2025
https://osu.zoom.us/j/92668696344?pwd=UVpzV2FmeU8ycGtaUzVtQ3FTNjJzdz09, at 16:00 (GMT), duration : 00:00

FWD Software

2025-02-19 11:00
America/New York
Wednesday, 19 February 2025
https://osu.zoom.us/j/92668696344?pwd=UVpzV2FmeU8ycGtaUzVtQ3FTNjJzdz09, at 16:00 (GMT), duration : 00:00