STAR HardProbes PWG

[Brennan Schaefer <brs521 AT lehigh.edu>]

Hi Yi, Sooraj, and HP team, I have posted another revision of the slides with the annotations again removed, and also every to-do item until 6 hours ago finished.  I am also available to iterate quickly over your comments.

https://drupal.star.bnl.gov/STAR/node/68993/

Specifically the comparison to the Raa in heavy-ion collisions was an idea I found in this paper,

   

   J/ψ Production as a Function of Charged Particle Multiplicity in pp Collisions at √s = 7 TeV

   https://arxiv.org/abs/1202.2816

Part of the original motivation for the first measurement of J/psi vs multiplicity was to reach lower multiplicity events using p+p.  In the above ALICE paper it states:

"The multiplicity dependence measured here will allow a direct comparison of the J/ψ production in pp to the one observed in heavy-ion collisions. With a mean value of dNch/dη of 24.1, the highest multiplicity interval shown in Fig. 3, for instance, corresponds roughly to 45– 50% centrality for Cu–Cu collisions at √sNN = 200 GeV [21]. In order to establish whether any evidence for a J/ψ suppression is observed already in pp, a proper normalization is needed. This could be provided by a measurement of open charm production in the same multiplicity bins. Corresponding studies are currently ongoing."

Also, the old model calculation that predicted the opposite behavior, did not feature MPI or percolation, which (as I gather it) are the leading explanations for the enhanced J/psi production in high multiplicity events.  As a follow up question, I would be greatly interested to know if most recent Pythia model calculations in other areas are including these features.  If so, it then looks like this type of measurement has had a large influence.

thanks,

b

On Sun, Sep 22, 2024 at 10:14 AM Yi Yang <yiyang429 AT gate.sinica.edu.tw> wrote:

Hi Brennan,

Thanks for the updated version and explanation. 

Before you have the final version of the talk, I have comments/questions on p2 and p3. 

 - p2: I don't understand the comparison to the RAA in heavy-ion collisions here. As you said in the previous page, the main purpose for this study should be to understand the production mechanism, but nuclear modification is different story. I am not sure if it is good way to do it. 

 - p3: It would be nice to provide a physics reason why the old prediction saying the yield is decreasing (what is the mechanism), not just show the plot. Probably you can (or you already have) combine with p5 to give a better explanation. 

Cheers,

Yi

+++++++++++++++++++++++++++++++++++++++++++++++++++
Yi Yang, Research Fellow
Institute of Physics, Academia Sinica
E-Mail: yiyang429 AT gate.sinica.edu.tw
Tel: +886-2-2789-6709
+++++++++++++++++++++++++++++++++++++++++++++++++++
-----Original message-----
From:Brennan Schaefer<brs521 AT lehigh.edu>
To:star-hp-l<star-hp-l AT lists.bnl.gov>
Date: Sun, 22 Sep 2024 16:41:43
Subject: Re: [[Star-hp-l] ] STAR presentation by Brennan Schaefer for HP2024 submitted for review

Hi Sooraj also Yi and other leaders,

An updated presentation (this one has red annotation of my accompanying thoughts) is linked below.  Most of the suggestions are implemented, a few that require editing plots are maybe some few hours away, but the slides are converging quickly.

https://drupal.star.bnl.gov/STAR/node/68993/

best,

b

On Sun, Sep 22, 2024 at 4:09 AM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:

Hi Brennan,

   Thanks. Please send the updated version as early as possible 

Best,

Sooraj

On Sun, Sep 22, 2024 at 12:09 AM Brennan Schaefer <brs521 AT lehigh.edu> wrote:

Hi Sooraj, I just sent an update on the main plot that I am requesting preliminary for.  I will send an update on the slides really soon (probably less than an hour).  best,   b

On Sun, Sep 22, 2024 at 3:04 AM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:

Hi Brennan,

   Do you have an updated version of your talk?

thanks,

Sooraj

On Fri, Sep 20, 2024 at 6:15 PM Yi Yang <yiyang429 AT gate.sinica.edu.tw> wrote:

Hi Brennan,

We saw an updated version on drupal now, thanks a lot.
Let me give you a very quick first round of comments.
 - Title: please add "Supported in part by" above the DOE logo, please check other's talk. Also, it would be good to add date of your talk there.
 - p1: I would start with the previous measurements on cross section vs pT and polarization and mention the production mechanism is still an open question. Then, introduce these CSM and COM.
 - p2: Not sure if you need this one, I don't know how you will connect it to your results.
 - p3: Need more description on this page, not sure what you want to say on this early predictions.
 - p4: references are need for this plot.
 - p5: small b^bar --> small impact parameter
 - Move p9 p10 (STAR) before p6.
 - p6: It would be nice to have some parameters showing on the plot, like NJ/psi, width, mean...
 - p7: B.EMCal --> BEMC   (2 places)
 - p8: the quality of the plot is not good, can it be improved? Also, can you make the data plots larger? Not easy to know the inserted plot mean, need some description.
 - p9: Add the abbreviations for each subsystem, like (BEMC), (TOF), (TPC), (BBC), (VPD)
 - p9: Remove the line under Vertex Position Detector
 - p10: add eta ranges for TOF and TPC
 - p11: You have a nice list for systematics sources in your preliminary request, I think it would be nice to add here.
 - p12: Add a title on this page: "Result"
 - p13: Not sure if you need this plot here, it would be better to have a summary, what Barbara sent (PYTHIA predictions) might be useful here.

Cheers,
Yi

+++++++++++++++++++++++++++++++++++++++++++++++++++
Yi Yang, Research Fellow
Institute of Physics, Academia Sinica
E-Mail: yiyang429 AT gate.sinica.edu.tw
Tel: +886-2-2789-6709
+++++++++++++++++++++++++++++++++++++++++++++++++++

-----Original message-----
From:webmaster AT star.bnl.gov
To:Star-hp-l AT lists.bnl.gov
Date:Sat, 21 Sep 2024 03:46:48
Subject:[[Star-hp-l] ] STAR presentation by Brennan Schaefer for HP2024 submitted for review

Dear Star-hp-l AT lists.bnl.gov members,

Brennan Schaefer (brennanschaefer AT hotmail.com) has submitted a material for a 
review, please have a look:
https://drupal.star.bnl.gov/STAR/node/68993

Deadline: 2024-09-22
---
If you have any problems with the review process, please contact 
webmaster AT www.star.bnl.gov

--

Sooraj Radhakrishnan

Research Scientist,

Department of Physics

Kent State University

Kent, OH 44242

Physicist Postdoctoral Affiliate

Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road

Berkeley, CA 94720

Ph: 510-495-2473

Email: skradhakrishnan AT lbl.gov

--

Sooraj Radhakrishnan

Research Scientist,

Department of Physics

Kent State University

Kent, OH 44242

Physicist Postdoctoral Affiliate

Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road

Berkeley, CA 94720

Ph: 510-495-2473

Email: skradhakrishnan AT lbl.gov