STAR HardProbes PWG

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

Hi Youqi,

Thanks for the answers, they look good to me.

Just a comment on s16. It's hard to quickly judge by eye which distribution is more steep so it might not be obvious to people. But you don't need the right plot to make this point. The first split should be basically the sum of the contributions that you show on your plot. So naturally it should be less steep than the blue, if green and yellow are flatter. With the z_g in R_g bins we show that we saw the np contributions to the first split and have a consistent picture - as you write in your backup. Which I think is a nice physics message. 

Cheers,

Barbara

On Thu, Mar 16, 2023 at 8:28 PM Youqi Song <youqi.song AT yale.edu> wrote:

Hi Nihar and Barbara,

Thanks for the feedback! I have implemented your suggestions in the slides here https://drupal.star.bnl.gov/STAR/system/files/dis_032823_v2.pdf. Please also find my response below and let me know if you have any other comments.

Best,

Youqi

------------------------------------

To Nihar's comments:

General comment/suggestion to all HP2023 and DIS2023 presenters:
1. Please make a Drupal page for all your preliminary plots and provide
us the link.
If you have already done that, please send us the link.

Here is the link. https://drupal.star.bnl.gov/STAR/blog/youqi/Multidimensional-jet-substructure-multifold-preliminary-figures. I moved my previous preliminary figures (M and Q) to this link too, and then realized that the link in PWG preliminary figure table https://drupal.star.bnl.gov/STAR/pwg/Hard-Probes/HP-PWG-Preliminary-plots doesn't work anymore, so you might also need to update that link. Sorry for the inconvenience.

Slide:15

3. Please follow Guidance -2 in the above link for this plot (X,Y-axis
title size).

These plots are from Monika's analysis. I will update them once she does. 

Slide16:

Left plot:

1. What is "~DGLAP: pQCD" ? The dashed lines are HERWIG7. Is not that?
Not sure what you want to point out here?

This arrow points to the most steeply falling dM=0 distribution, not HERWIG specifically. I have made the text clearer.

 

2.      "The more mass that is groomed away relative to the original mass,
the flatter the Zg distribution"
           Apparently this is not the case in left side plot. It shows
the decreasing trend with increase in Zg although there is a relative
difference.

I am not sure I understand your question here. The behavior that I am quoting here is that as you move from the blue markers to green and then to orange (increasing dM/M), the zg distribution becomes flatter. We are not trying to make any statement about how dM changes with increasing zg.

3. "Demonstratesthatinitialsoftwideangleradiation constrains the
momentum imbalance of & the amount of NP contributions to later
splittings" Not sure how we draw this conclusion on NP.

We conclude that there is more NP contribution because the zg distribution is flatter. More steeply falling zg resembles the pQCD DGLAP splitting function more, so conversely flatter zg is a signal of more npQCD behavior.

 

4.      "The first splitting that passes SoftDrop can still be
non-perturbative"
But from the STAR paper (right side plot), did not we draw a conclusion
that 1st split is from perturbative contribution and follow the
splitting kernel?

My understanding (feel free to correct me) is that they conclude that on an ensemble level, the 1st splits are more dominated by perturbative effects, compared to later splittings, but there could still be variation in the amount of perturbative effects for each splitting individually. 

"Jets with a large perturbative contribution can be enhanced by
selecting on small collinear drop mass"
Can you point to me from which plot you draw this conclusion?

 In the previous slide, by comparing my dM=0 zg curve with the first split from the zg vs # split plot, we see that when we select on dM=0, we can get a zg curve that's even steeper than the inclusive first split, so we enhance the pQCD contribution even more.

To Barbara's comments:

- s12: there might be a question here why you exclude the dM = 0 cases. And the 45% fraction is estimated how, from which MC, on true or reco level ? Fraction from the data that you quoted before was 37%.

 Since there is a large fraction of dM = 0 jets, if I include them it will make the first bin have much more counts and blur out the peak at nonzero dM that's visible in the plots now. The theorist says that his prediction would also be just for the jets with nonzero dM.

The 45% (now changed to 45.5% to be more precise) is taken from data after unfolding and efficiency correction. The previous 37% is from raw data. It's much smaller since the jets with 20-30 GeV at raw data level on average correspond to higher unfolded pT, and higher pT jets on average have a smaller fraction of dM = 0.

- s15: could you please explain the transition between s14 and 15, and how you're going to connect the two ? 

 I will summarize that slide 14 tells us how Rg of a later splitting correlates with an earlier splitting mass contribution, but we can also look at how Rg correlates with the mass contribution at the *same splitting* that this Rg characterizes, which would bring me to slide 15. And we arrive at the second bullet point of slide 15 "Rg controls the mass contribution to the early stage of the jet but not the later emission" by comparing the two slides.

- s15: use a better quality plot

This plot has low quality because the x-axis is screenshotted from a different panel. I will communicate with Monika and replace it with a better plot.

- 16: I wonder if it's not better to show here Monika's zg plot in Rg bins, instead of zg for different splittings. It can show better the different contributions to the first split. 

Also, please use the preliminary version of the figure.

I would like to show the comparison with zg for different Rg too if there's more time. I have included a slide on it in backup. With this zg vs # split plot here, I was trying to make the point that, with the dM=0 cut, we can get a zg curve that's even steeper than the inclusive first split, so we enhance the pQCD contribution even more.

I got this figure from https://drupal.star.bnl.gov/STAR/system/files/Paperplot_JetpTbins_v2_Zg_ppJP2_Run12_R4_vs_MC.pdf, with some of the text screenshotted from the 30-50 GeV panel. Is there a newer version of this figure?

On Thu, Mar 16, 2023 at 8:00 AM Barbara Trzeciak via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi Youqi,

nice slides. Please see my comments below.

- s2: I suggest having the SoftDrop condition somewhere, as you mention it on the following slide.

You need to explain to people the SoftDrop first, before you proceed to the Collinear drop, otherwise people who don't know SD will get lost at the beginning.

- s3: I suggest to label the right sketches - the top one corresponds to the collinear drop and the one below to the soft drop

- s3: Observables - since it's a motivation slide and you describe your exact observable later, I would suggest to replace it here with a more general observable: Delta m^2 = Delta m_SD1^2 - Delta m_SD2^2

- s3: Do you need the PYTHIA plot here ? It's nice but the slide is already quite busy, and you would need some time to explain it. 

- s6: Motivation → Method -> Method

- s7: enlarge the soft grooming condition

- s8: move "neutral pT fraction < 0.9" to a separate line

- s10: improve quality of the M equation

- s12: there might be a question here why you exclude the dM = 0 cases. And the 45% fraction is estimated how, from which MC, on true or reco level ? Fraction from the data that you quoted before was 37%.

- s12: pT -> p_T

- s12: since you have some space here, you can add information that the PYTHIA8 Detroit is a new tune, tuned on STAR data.

- s14: dM is not defined

- s15: could you please explain the transition between s14 and 15, and how you're going to connect the two ? 

- s15: add that it agrees with MC

- s15: use a better quality plot

- s16: ~ DGLAP: pQCD - I would add "1/z"

- 16: I wonder if it's not better to show here Monika's zg plot in Rg bins, instead of zg for different splittings. It can show better the different contributions to the first split. 

Also, please use the preliminary version of the figure.

- s14,16: yo show comparisons with PYTHIA8 and HERWIG7, it would be good to comment on this.

Cheers,

Barbara

On Tue, Mar 14, 2023 at 4:13 PM webmaster--- via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

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

Youqi Song (youqi.song AT yale.edu) has submitted a material for a review, 
please have a look:
https://drupal.star.bnl.gov/STAR/node/62961

Deadline: 2023-03-27
---
If you have any problems with the review process, please contact 
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