STAR HardProbes PWG

[Youqi Song <youqi.song AT yale.edu>]

Hi Nihar,

Thanks for the comments! Please find my response below. I have also updated my slides on drupal.

Slide 7: "PYTHIA No hadronization" means I ran PYTHIA specifically with a flag "HadronLevel:Hadronize = off".

Slide 11: t_1,2,3 are "Lines of constant formation time" as I have as a bullet point on the slide. I will also make sure to verbally emphasize that as I present. The equation that I have on the slide 𝑧 = 1/2  [1−√(1−2/𝑡𝐸(1−cos(𝜃)) )  ]) gives a function of z(theta) once the value of (t*E) is fixed, and as I vary (t*E) to different values, for example, 50, 200, 800, I get different functions of z(theta).

When you said to make a 2D plot of zg vs Rg in pp data, do you mean making an internal plot with uncorrected data?

Slide 15: I have weakened the statement to "In the future, one might potentially measure this in heavy-ion collisions!"

Slide 18: I am not using any hard-core selection. I have changed the statement to "Weak dependence on jet 𝒑_𝐓 in 20-40 GeV"

rc vs formation time: I have made this plot with uncorrected data and it is in slide 5 of https://drupal.star.bnl.gov/STAR/system/files/pwg_meeting_051123.pdf. I have temporarily shifted away from measuring rc with respect to the formation time, because after our PWG discussion in May, I am also not sure if a formation time defined in terms of leading hadron kinematics is meaningful. And my conclusion from that discussion is that if I'd like to make connection to formation time, then I need to measure it with groomed subjets, which are better proxies for partons.

Best,

Youqi

On Mon, Jan 29, 2024 at 7:44 PM Nihar Sahoo via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hello Youqi,

Please find my comments and queries on your nice slides.

Slide3:
Use “𝑔 ” -> it looks eerie in this way, you could mention "subscript 𝑔 ”

Slide7: "Note: Hadronization effects smear the distribution but don’t
affect the correlations" and backup slide-28
In the backup slide, what is "PYTHIA No hadronization"? Do you mean you
check the effect of harmonization comparing parton level and with
hadrons using PYTHIA?
I forgot this discussion, can you pleas remind me again? Thank you
_ you could show lower bottom plot of slide28 in this slide.

Slide11:
Please provide reference to these expressions like formation time and z.
Mention what are t_1,2,3 in side the plot? And what are 50, 200, 800
here?

_Can you make similar right 2D-plot (zg vs Rg) for pp data ?


Slide12:
Interesting!
This discussion mainly based on HERWIG.
I see now this "What will data tell us? Stay tuned! "
I would make it Bold and bigger, place somewhere people can see this. It
is lost inside. [same on Slide11 too]


Slide15:
-In the future, potentially measure this in heavy-ion collisions! -> I
have been seeing this but never commented yet. But I think in heavy-ion,
it would not be that easy. So better to be cautious on this statement.


Slide18:
Weak dependence on jet 𝒑𝐓 -> probably not correct or difficult to say
because: 1) depend on jet selection (hardcore vs inclusive jet
population) 2) we don't show full jet pT range, say below 20 GeV/c.
Suggestion: either remove it or mention what jet population and within
jet pt range.

Not related to your this presentation:
As you have seen Charles presentation on r_c vs formation time plot.
Could you make similar plot for your analysis to see what is the trend?
We can discuss at hp-pwg in your next presentation if you could.


Thank you
Nihar



<div class="pre">On 2024-01-30 02:13, webmaster--- via Star-hp-l
wrote:<blockquote>Dear <a
href=""mailto:Star-hp-l AT lists.bnl.gov">Star-hp-l AT lists.bnl.gov</a>
members,<br>
<br>
Youqi Song (<a
href=""mailto:youqi.song AT yale.edu">youqi.song AT yale.edu</a>) has submitted
a material for a review,  <br>
please have a look:<br>
<a rel="noreferrer" target="_blank"
href=""https://drupal.star.bnl.gov/STAR/node/66663">https://drupal.star.bnl.gov/STAR/node/66663</a><br>
<br>
Deadline: 2024-02-11<br>
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