STAR HardProbes PWG

["Mooney, Isaac" <isaac.mooney AT yale.edu>]

Hi all,

Thanks for all the very helpful comments. A new version (v4) that implements comments from Sooraj, Rongrong, and Helen (offline), as well as some changes I had planned to make (most importantly I added a slide referencing the GPC#359 paper since it was just accepted by PRC a few days ago), is now on the node. There are a few points of beautification left (making sure I have the highest-res, newest plot in all cases; color-matching cartoons/datapoints/etc. when possible; font size/style regularization; etc.) but I think otherwise it’s getting pretty close. I have responses to comments below, and please let me know if there are any more before sign-off. Note: the talk is on Monday at 11:15 JST (Sunday at 10:15 PM EDT), ideally posted an hour in advance of that.

Thanks,

Isaac

Rongrong:

slide 5

- "perfectly correlated" points to empty space? -- Yes, it's -1, but the axis ends at -0.8, so I drew the arrow to approximately where the -1 value would be.

slide 8

- It might be better to show jet dv1/dy vs. pt plot. -- Why do you think so? It seems we can extract much of the same information from each given that the slopes are written on this plot. It seems a bit more complicated to me to show the dv1/dy vs pT.

- I do not think our data can rule out possible pT dependence. The statement of "independent of jet p_T" is a bit too strong, especially given that we do not correct for jet p_T. -- Sorry, I meant the fact that there is a finite v1 persists across the pT and R studied. But I have reworded.

slide 9

- I suggest to show the R = 0.4 plot since the effect is supposed to be stronger for larger jets. -- Okay, I showed the R = 0.2 plot because it had the smallest uncertainties, but I have switched it.

- It is important to highlight in the figure and emphasize in the text that this measurement is for jets with pT_raw > 9 GeV/c and pT_cons > 2 GeV/c. The effect could be there if we go to lower jet or consistent pT. -- I guess I agree with you, but this will be a little tricky to mention without making it seem like there is a future plan for STAR to go to lower pTs, which I don't think there is (Gabe can correct me if I'm wrong). I will think of a good verbal wording to address this.

 

slide 10

- since you focus on radius dependence, maybe remove the left figure to save you some time -- Originally I had removed this figure, but I make a comment about it in the conclusions so I wanted to show it on the slide so it doesn't come from nowhere. In practice, the time consuming part is the first bullet anyway, so I think it is okay to keep, but I will remove it if I'm really struggling on time as I continue to practice.

- "predict minimal suppression": I think you want to say minimal radius dependence of the suppression -- great point, fixed.

slide 12

- The text size is significantly larger than other slides. Maybe make them consistent -- Yes, I'll go through once I have somewhat finalized bullet points and make sure they are all consistent. It's 48-point throughout, but with more text it automatically shrinks to fit.

- Consistent with SPS at 17.3 GeV -- good catch, thanks.

slide 14

- For the LHC results, are they measured using mid-rapidity J/psi and mid-rapidity multiplicity as we do? If not, it won't be a fair comparison. -- Yes, it's also midrapidity for J/psi and multiplicity.

slide 16

- Your conclusions are based on the extracted temperatures. I suggest to make them significantly bigger. -- done.

slide 19

- It might be useful to make it clear that this measurement is w.r.t. the event plane -- good point, done.

slide 20

- "First measurements": many other results are also first measurements, or you mean something else? -- Good point, I've removed it. It's not part of the physics conclusion anyway.

- How does r_c cleanly separate perturbative and non-perturbative physics? -- I've reworked the takeaways slide. Please let me know if you have any comments on it.

- Add some qualification to the third bullet -- done.

slide 21

- "minimal impact of regeneration at RHIC energies": on slide 12, model calculation shows that about half of the J/psi come from regeneration at 200 GeV. Probably add "below 62.4 GeV"? - done (I said ~60 GeV).

- Third bullet does not read like a physics message -- see above message about reworking.

Sooraj: 

S3: We have results on stream 5 also, right? Why not add a cartoon for that as well? -- Absolutely, just had to think about what to make the cartoon. I have a cartoon now.

S5: What is the arrow 'perfectly correlated' pointing to? -- It's pointing to -1, because that doesn't exist on the axis. I will make it clear as I speak.

S5: I think the difference between random track pairs and leading track pairs should be pointed out. Otherwise will be difficult for audience to read the plot -- I'm not exactly sure I understand the suggestion, but for other reasons I changed the first bullet to start with "Leading charged correlator, r_c,..." Does this address your comment too?

S8: Outlook is not just ESE, so would suggest to remove the last bullet. v_1 has several advantages compared to other probes, so you can point to the talk to see details on the measurement and why they are interesting -- I originally removed it as you requested, but Helen thought I should have an outlook on each slide, so I've added it back in. Of course, in most of the slides the outlook isn't the single thing left to be done, and I will try not to make it seem that way. If you'd like a different thing highlighted as the outlook, feel free to let me know and I can replace what is currently there with that.

S9: Does the left plot add anything to discussion? -- Yes, I think so. It's the theoretical prediction that lead to the measurement. It shows the behavior we might expect (at least for the kinematics they studied).

S9: Could show the result with previous constituent threshold here. That way your statement will be clear. Currently the emphasis is not clear -- why? I show all of the new results for the other talks. It feels odd not to highlight Gabe's new work. I tried to clarify in the text, please let me know if that is okay.

S10: Why dod you say models predicting minimal suppression? The left plot with LIDO is showing suppression. Minimal R dependence? -- Yes good point, it was a bad wording.

S12: I think the pT dependence could be more interesting, or that could also be shown on the right. -- Since I'm highlighting especially the newest energy of 17.3 GeV, which only has two pT bins, I prefer the sqrt(s) dependence. I think if I had more time, I would agree with you that I could add the pT dependence plot on the right, but in 15 minutes, I would prefer to just pick one to highlight. I can mention verbally that the pT dependence was also studied.

S14: Do you have a better resolution version for this plot? -- Using the new version from Brennan, this is fixed. But in general, I've just been screenshotting from people's talks, but will make sure I have the best resolution version possible in each case.

S19: Title could be changed to photon induced J/Psi polarization -- I tried to make all of the slide titles related to the physics message rather than the observable / talk name. 

S20: Third bullet is not correct. Why not say what is measured, no enhancement of p/pi ratio within jets? -- how is it not correct? We observed a medium-induced hadrochemistry effect? I'm trying to keep the physics conclusions fairly broadly applicable here.

S21: Are MPI the only proposed explanation? String percolation and change of soft multiplicity are also proposed, right? -- I added string percolation, good point.

S23: I think you will update the Nx? -- Yes, still TBD, but will do ASAP.

On Sep 22, 2024, at 03:36, Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:

Hi Isaac,

   Thanks for the updated version and implementing the comments from the rehearsal. Please find some further comments below 

S2: I think this slide is still quite busy. Could you move the boxes for ZDC and VPD away from the figure? Why highlight BBC while you point to other sub-systems?

S3: We have results on stream 5 also, right? Why not add a cartoon for that as well?

S5: What is N_cc?

S5: What is the arrow 'perfectly correlated' pointing to?

S5: I think the difference between random track pairs and leading track pairs should be pointed out. Otherwise will be difficult for audience to read the plot

S8: Please use the cartoon from my presentation

S8: I would like to highlight here as 'a new observable to probe path length dependent energy loss in QGP' (second bullet)

S8: Have the definition only for v1

S8: Outlook is not just ESE, so would suggest to remove the last bullet. v_1 has several advantages compared to other probes, so you can point to the talk to see details on the measurement and why they are interesting 

S8: I would prefer this plot that pT dependence, as the slope is an extracted quantity 

S9: Does the left plot add anything to discussion?

S9: Could show the result with previous constituent threshold here. That way your statement will be clear. Currently the emphasis is not clear 

S10: Why dod you say models predicting minimal suppression? The left plot with LIDO is showing suppression. Minimal R dependence?

S10: Outlook: could say what is the increase in statistics expected. adding generalized --> measuring generalized. Can remove the last one. What is the tightening you refer to here?

S12: I think the pT dependence could be more interesting, or that could also be shown on the right. 

S12: expected to be

S14: Do you have a better resolution version for this plot?

S19: gamma induced J/Psi polarization 

S19: Title could be changed to photon induced J/Psi polarization 

S19: Due to photon linear polarization and ...

S20: Third bullet is not correct. Why not say what is measured, no enhancement of p/pi ratio within jets?

S20: The uncertainties currently are quite large to conclude the latter part of the last bullet here. You could say same as in the slide, within uncertainties no broadening seen

S21: Are MPI the only proposed explanation? String percolation and change of soft multiplicity are also proposed, right?

S23: I think you will update the Nx?

Best,

Sooraj

On Fri, Sep 20, 2024 at 11:16 AM Ma, Rongrong <marr AT bnl.gov> wrote:

Hello Youqi

Thanks for pointing me this very nice study. 

So the difference between data and MC could be due to that the resonance decay contributions are different, right? I feel this is an important aspect that should be stated.

Do you have a similar plot for HERWIG as what's shown on your slide 22 for PYTHIA? This could help us understand better the difference between the two. 

On your slide 23, top table, the percentages for those resonances in HERWIG add up to 43%. What other resonances do these leading pi+ originate from in HERWIG?

Best

Rongrong

On Sep 20, 2024, at 12:40 PM, Youqi Song <youqi.song AT yale.edu> wrote:

Hi Rongrong,

I would like to clarify this point you raised:

Here HERWIG7 and PTYHIA8 predict basically same r_c values. Given that HERWIG uses clusters while PYTHIA uses strings, does this mean there are something else that dictate r_c values rather than the fragmentation scheme? 

In addition to string or cluster hadronization, we now believe that resonance decays could also play a role. I have details of this study in my slide 9 and backup slides 22 and 23. But to summarize, I found that if I look at the parent of the leading track in jet, then: 

In PYTHIA, 50% of the time it’s from a quark or diquark, and 50% of the time it’s from resonance decay.

In HEREIG, 30% of the time it’s from a cluster, and 70% of the time it’s from resonance decay.

So one takeaway is that although PYTHIA and HEREIG predict the same r_c, there is actually a huge difference in how they arrive at it.

On the other hand, a lot of these resonance decays are what we call “sign preserving”, eg, rho+ goes to pi+ pi0, so when we measure a leading pi+, we still have the charge information from its rho+ parent.

Best,

Youqi

On Fri, Sep 20, 2024 at 11:14 AM Ma, Rongrong <marr AT bnl.gov> wrote:

Hello Isaac

Very nice set of slides to showcase STAR results. 

I have some comments for your consideration. 

- While it is already challenging to highlight 10 talks, still I think it will be good to include at least new preliminary results from posters since yours is the only STAR highlight talk. If we do not highlight them, others won't either. 

slide 2

- not sure if "Zr+Zr, Ru+Ru" in gray is easy to see on a projector

- remove "provides"

slide 5

- text beneath is a bit too small

- "perfectly correlated" points to empty space?

- "Pythia predicts more string-like fragmentation": I thought there is only string-like fragmentation in Pythia, but this statement seems to imply that there are other fragmentation mechanisms. What are they?

- Here HERWIG7 and PTYHIA8 predict basically same r_c values. Given that HERWIG uses clusters while PYTHIA uses strings, does this mean there are something else that dictate r_c values rather than the fragmentation scheme?  

slide 8

- It might be better to show jet dv1/dy vs. pt plot. 

- I do not think our data can rule out possible pT dependence. The statement of "independent of jet p_T" is a bit too strong, especially given that we do not correct for jet p_T. 

slide 9

- I suggest to show the R = 0.4 plot since the effect is supposed to be stronger for larger jets.

- It is important to highlight in the figure and emphasize in the text that this measurement is for jets with pT_raw > 9 GeV/c and pT_cons > 2 GeV/c. The effect could be there if we go to lower jet or consistent pT. 

 

slide 10

- since you focus on radius dependence, maybe remove the left figure to save you some time

- "predict minimal suppression": I think you want to say minimal radius dependence of the suppression

slide 12

- The text size is significantly larger than other slides. Maybe make them consistent

- Consistent with SPS at 17.3 GeV

slide 14

- For the LHC results, are they measured using mid-rapidity J/psi and mid-rapidity multiplicity as we do? If not, it won't be a fair comparison. 

slide 16

- Your conclusions are based on the extracted temperatures. I suggest to make them significantly bigger. 

slide 19

- It might be useful to make it clear that this measurement is w.r.t. the event plane

slide 20

- "First measurements": many other results are also first measurements, or you mean something else?

- How does r_c cleanly separate perturbative and non-perturbative physics?

- Add some qualification to the third bullet

slide 21

- "minimal impact of regeneration at RHIC energies": on slide 12, model calculation shows that about half of the J/psi come from regeneration at 200 GeV. Probably add "below 62.4 GeV"?

- Third bullet does not read like a physics message

Best

Rongrong

On Sep 19, 2024, at 4:01 PM, Mooney, Isaac <isaac.mooney AT yale.edu> wrote:

Hi all,

v2 uploaded now with comments from the STAR practice talk addressed. Will be uploading a v3 with comments from the Yale group implemented as well. Not sure yet of the timescale for that version as I need to prepare for the trip tonight.

Thanks,

Isaac

On Sep 18, 2024, at 22:27, Mooney, Isaac <isaac.mooney AT yale.edu> wrote:

Hi all,

Trimmed version (v1) uploaded now (aesthetics still to be improved).

Thanks,
Isaac

On Sep 18, 2024, at 20:01, Mooney, Isaac <isaac.mooney AT yale.edu> wrote:

Hi all,

This is a rough draft of the talk. The organizers today let us know that the talks in this session are 15’+5’. So I am in the process of significantly trimming down. I’ll upload a new draft when that is done, but wanted to let you see the talk as soon as possible. PS I am aware that the aesthetics are not good right now — I will improve them in a future version.

Thanks,
Isaac

On Sep 18, 2024, at 19:55, webmaster AT star.bnl.gov wrote:

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--

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