STAR HardProbes PWG

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

Hi Nihar,

Sounds good! I will bring up these discussions again next time I present at the PWG meeting. Please let me know if you have any additional comments. Thank you!

Best,

Youqi

On Tue, Jan 30, 2024 at 9:24 PM Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> wrote:

Hello Youqi,

Thank you for your replies. Please find my reply below.

> 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?
I mean not for this presentation. you can present these results at our
next pwg-meeting.

> 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.
Thank you for pointing this presentation.
Yes, that is true.
OK, let's discuss at your next presentation. Please bring this discuss
again also.

Best
Nihar


On 2024-01-30 07:24, Youqi Song wrote:
> 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>
>> ---<br>
>> If you have any problems with the review process, please contact
>> <br>
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>>
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