STAR HardProbes PWG

[Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>]

Hello Youqi,

Please find my further comments inline.


On 2023-03-17 00:57, Youqi Song 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.
Thank you.
There are some figures they need some work.
Like
1) https://drupal.star.bnl.gov/STAR/system/files/rg_dmfrac_2d_wtext.png
Please put the text away from the data and make larger font size. It is 
not visible.
You may place at the right corner making little room there.

2)https://drupal.star.bnl.gov/STAR/system/files/dmfrac_rg.png
You need to mention what is "N" in y-axis? like "N_{jet}"
Same for other plots.


> > 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.

Then I would not put "Steeply falling..." inside the figure with arrow.
Please move that outside the figure and make another bullet.

> > 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.

OK, Thank you.
Mention what is "NP contributions"? "NP" ?

> > 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.

"if we apply the dM=0 selection, we can filter out the jets with large 
np contribution"
I would not say "filter out the jet with _large_ np contribution"
As we don't know if it is truly np contribution or other splitting 
kernel or just coming from hadronization.

Better to use a mild statement like
"if we apply the dM=0 selection, we may filter out some npQCD 
contribution to the parton splitting"

> > "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.

Then I would paraphrase like following.
"Jets with a large perturbative contribution can be enhanced by 
selecting on small collinear drop mass"
-> "Jets with a DGPLAP-like splitting can be enhanced by smaller 
collinear drop mass selection."


Thank you
Nihar

> 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
> > > webmaster AT www.star.bnl.gov
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