Title:
Measurement of Groomed Jet Structure Observables in p+p Collisions at \sqrts = 200 GeV with STAR

Abstract:
In this letter, a comprehensive suite of jet sub-structure measurements via the SoftDrop algorithm including the shared momentum fraction ($z_{\rm{g}}$) and the groomed jet radius ($R_{\rm{g}}$) are reported in \pp collisions at $\sqrt{s} = 200$ GeV collected by the STAR experiment. These sub-structure observables are differentially measured for jets of varying resolution parameters from $R = 0.2$ to $R = 0.6$ and transverse momentum range $15 < p_{\rm{T, jet}} < 60$  GeV$/c$. This study shows that with increasing jet radius and jet energy, the $z_{\rm{g}}$ distribution asymptotes to the DGLAP splitting kernel at RHIC kinematics. The groomed jet radius measurements reflect a momentum-dependent narrowing of the jet structure for jets at a given radius, i.e., the larger the jet $p_{\rm{T, jet}}$, the narrower the first split. For the first time, these fully corrected measurements can be compared to leading order Monte Carlo generators. We observe that RHIC-tuned PYTHIA-6 is able to quantitatively reproduce data whereas the LHC-tuned event generators, PYTHIA-8 and HERWIG-7, are unable to provide a simultaneous description of both the $z_{\rm{g}}$ and $R_{\rm{g}}$, resulting in opportunities for fine parameter tuning of these models in \pp collisions at varying collision energies.

PA :
Raghav Kunnawalkam Elayavalli¹, Joern Putschke¹, Kolja Kauder²
1- Wayne State University, Detroit MI
2- Brookhaven National Lab, Long Island NY

Target Journal :
Physics Letters B.

Referee Comments : doc
Paper draft :  v17  
Supplementary material : pdf

Referee Comments Round 2 : doc
Paper draft : v19
Supplementary material : pdf

Paper Code Directory : psn0718

Analysis note : Draft v10

Collaboration Review  - Combined responses link
1. IHEP Protovino - link
2. Kentucky - link
3. NTU - link
4. Shandong - link
5. UC Riverside - link

GPC :
Chairperson: Rongrong Ma
Member(s) at large: Matthew Kelsey
Member for English/Grammar QA: Sevil Salur
Member for Code QA: Huanzhao Liu
PWG representative: Hanseul Oh

Comments (and PA replies) from the GPC:
[Before official start of GPC] Comments from Sevil on April 16th on paper draft v2 link
1) Rongrong Ma April 29th on paper draft v3 and analysis note draft v4 link
2) Matthew Kelsey April 30th on paper draft v3 and analysis note draft v3 link follow-up link

GPC Meetings:
Thursday May 2nd 2019: 12:00-13:00 EST
BlueJeans meeting ID: 696 984 331
Slides link

Thursday July 11th, 2019: 12:00 - 13:00 EST
Bluejeans meeting ID: 756 623 593
Slides link

Paper Proposal Talk : v1

Paper Plots:

Fig1.

Fig3.

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Tables 1,2

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Conclusions: 

Public Presentations On Behalf of STAR Collaboration: 
Hard Probes  Aix Les Baines October 2018
High pT Workshop, Knoxville TN March 2019

Invited Presentations By PAs: 
JETSCAPE Workshop  TAMU Jan 2019
UCLA Jet Workshop   UCLA Jan 2019

Jet Corr Presentations:  (These are only the presentations focused on the pp analysis)
1. Feb 27th 2018 - https://drupal.star.bnl.gov/STAR/blog/elayavalli/groomed-jet-radius-pp-run12-first-analysis-update
2. July 10th 2018 - https://drupal.star.bnl.gov/STAR/blog/elayavalli/jetcorr-pp-rg-systematics-analysis-update
3. Sept 4th 2018  - https://drupal.star.bnl.gov/STAR/blog/elayavalli/sept-4th-jetcorr-jet-internal-structure-analysis-update