STAR HardProbes PWG

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

Hi Nihar,

We aren't planning to include this projection on slide 35 in figure 2, since the information is contained in the left hand side 2D plot. I would agree that from slide 35, we see that dM=0 jets have on average a larger angular scale for the first splitting, and vice versa. But I'm not sure why you think that's related to the zg plot in figure 3. Are you trying to make a connection to Monika's measurement where we see that large Rg jets have a more steeply falling zg?

Best,

Youqi

On Fri, Mar 10, 2023 at 11:09 AM Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> wrote:

Hi Youqi,

Thank you for preparing this plot in slide 35.
Do you want to include this figure as one panel of Fig2?

Now if I compare Zg of fig -3 and Rg plot on slide 35, it looks like no
grooming (dM=0) case jets have wider angle and vice versa. Is that
correct?

I will send email request to Rongrong by tomorrow, I am traveling.

Cheers
Nihar


On 2023-03-10 17:35, Youqi Song wrote:
> Hi Nihar,
>
> In case my other email got lost in the thread for this week's PWG
> meeting, I would like to point you to slide 35 of
> https://drupal.star.bnl.gov/STAR/system/files/prelim_request_030923.pdf.
> This might answer your question regarding:
>
>> Do you have a plot to show for different "Delta_M/M" what is the
>> distribution of "Rg"?
>> You could add another panel plot with Fig.3 to show Rg distribution
>> (Similar to Zg distribution).
>>
>> It is important to show for different "Delta_M/M" regions later
>> splitting dominates by showing Rg distribution in this measurement.
>
> Please let us know when you put in the request for PWGC review to
> Rongrong. Thank you!
>
> Best,
> Youqi
>
> On Mon, Mar 6, 2023 at 2:34 PM Youqi Song <youqi.song AT yale.edu>
> wrote:
>
>> Hi Nihar,
>>
>> Thanks for the comments. I have updated my slides here:
>>
> https://drupal.star.bnl.gov/STAR/system/files/star_collab_meeting_030623.pdf.
>> In addition to Raghav's comments, please find my response below:
>>
>> Best,
>> Youqi
>>
>>> Slide 4:
>>
>>> Where is "PYTHIA6 STAR" on left side "Delta M" plot? And same for
>>> Fig.2 right.
>>
>> We think that a comparison with the PYTHIA8 Detroit tune should be
>> sufficient and better since it is a tune that includes newer RHIC
>> data.
>>
>>> What is "Delta_M" distribution for q vs g jet for this collinear
>>> drop jet measurement? Can we say something here on this? It would
>>> be an important information.
>>
>>> Can we add some PYTHIA simulation for the q vs g jet for these
>>> plots?
>>
>> Please see slide 5 in the updated slides for these.
>>
>>> Slide07
>>> "       "Observed an anti-correlation between the amount of
>>> early-stage
>>> radiation and the angular scale of a later-stage splitting, where
>>> a
>>> large groomed jet radius indicates small or no branching prior to
>>> the
>>> SoftDrop splitting "
>>> This statement is not clear what exactly it says.
>>>
>>> I think this conclusion is coming from the statement (Slide-5) of
>>> "the
>>> dM/M distributions anti-correlated with Rg"
>>> Then it is not clear how do we know these are "early-stage
>>> radiation"
>>> and "later-stage splitting".
>>> More explanation or better paraphrase is needed to make it clear.
>>
>> Raghav answered this in his response to slide 6 question 3: "the
>> early splits are defined via the definition of the formation time in
>> QCD which is inversely prop to angle and energy - taken from the
>> splitting functions." I think the cartoon on slide 16 (of the new
>> version) also helps illustrate this point.
>>
>>> "Agreement/disagreement with MC event generators (pending
>>> finalizing
>>> systematic uncertainties)" -> Figures 1,2, and 3 show that MC
>>> event
>>> generators are in agreement with the data. Is not that?
>>> Then why "/disagreement"?
>>
>> We think it's possible that after finalizing the systematics, the
>> error bars in the figures would become smaller and not cover some of
>> the MC curves. In any case, the main physics message of this
>> measurement (correlations between dM vs zg and Rg) is drawn from the
>> data themselves, and wouldn't be affected by the comparison with the
>> MC.
>>
>>> Slide-11
>>>
>>> Are we going to include Jet M distribution as one of supplementary
>>> figures?
>>> If yes, then it is not clear why do we need this figure as
>>> supplement
>>> material? Particularly "M vs Q".
>>> It sounds like a bit arbitrary.
>>> Could you explain here?
>>
>> We don't plan to include the jet M distributions in supplementary
>> material. As for whether to include "M vs Q", I will leave that
>> decision to Helen and Raghav.
>>
>>> Slide-18,19:
>>>
>>> It shows "hadronization" has biggest effect on the collinear drop.
>>> Then how reliable is it to say about early and later splitting as
>>> we
>>> mention in Slide 6-7?
>>
>> Like we have mentioned on slide 19 (slide 20 of the new version),
>> "hadronization smears/shifts the distributions, but the correlation
>> with and without hadronization is the same." For example, in the top
>> left figure of slide 20, when we turn off hadronization, in the
>> dashed curves, dM/M decreases with increasing Rg (as we move from
>> blue to green to orange). This is the same trend as the solid curves
>> with hadronization on. Similarly, for the top right figure, the
>> flattening of zg with increasing dM/M is the same trend between the
>> dashed and solid curves.
>>
>> On Mon, Mar 6, 2023 at 1:17 PM Raghav Kunnawalkam Elayavalli via
>> Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:
>>
>> Hi Nihar,
>>
>> Please find a few quick answers from the airport to your questions
>> below. I will respond to the rest later today after i land and get
>> to my destination.
>>
>> Cheers
>> Raghav
>>
>> **************************************
>> First Name - Raghav
>> Last Name - Kunnawalkam Elayavalli
>> email - raghav.ke AT vanderbilt.edu
>> website - https://www.raghavke.me  [1]
>>
>> RHIC/AGS UEC member
>> Assistant Professor of Physics
>> Stevenson Center 6410
>> Physics & Astronomy Department
>> Vanderbilt University
>> Nashville, TN 37235-1807
>> <they/them>
>> **************************************
>>
>> On Mar 2, 2023, at 7:07 AM, Nihar Sahoo via Star-hp-l
>> <star-hp-l AT lists.bnl.gov> wrote:
>>
>> Hello Youqi,
>>
>> As I mentioned we will discuss with Rongrong to find a nearest date
>> for PWGC review.
>>
>> In the mean time, Please find my comments below on these nice
>> results.
>>
>> SLide-4:
>>
>> What is the extra information we get from the right side plot of
>> obeservable "a"? Is not that the left plot "Delta M" is sufficient
>> to measure Collinear drop observables?
>> The quick answer for us is that - theorists are able to calculate
>> ‘a’ as opposed to ‘\delta M’ because a is normalized by the
>> jet pT. this makes the calculation in SCET doable and easier on the
>> theoretical uncertainties as they don’t need to vary the energy
>> scale.
>>
>> Where is "PYTHIA6 STAR" on left side "Delta M" plot? And same for
>> Fig.2 right.
>> We can certainly add it to the plots as we have done in the past.
>> Given that we have the pythia 8 detroit tune here, it more or less
>> covers the variation.
>>
>> What is "Delta_M" distribution for q vs g jet for this collinear
>> drop jet measurement?
>> Can we say something here on this? It would be an important
>> information.
>> from a purely conceptual basis - we know that the jet mass
>> distinguishes q vs g jets, we also know that groomed mass
>> distinguishes q vs g less but we can assume that the discriminative
>> power is probably less. Therefore, delta-m, i would naively assume
>> has a much weaker ability to distinguish between q vs g jets. In our
>> sample of jets, the q vs g fraction steadily increases from about
>> 60-40 for the 20ish GeV jets. so increasing the jet pT does change
>>
>> Can we add some PYTHIA simulation for the q vs g jet for these
>> plots?
>> I think we had truth level quark and gluon jet curves for the m vs
>> charge back during the preliminary discussion. Based on the
>> discussion i mentioned above, we can produce this curve but i hope
>> it doesnt hold up the forward progress on the paper.
>>
>> Slide-6:
>>
>> 1. Do you have a plot to show for different "Delta_M/M" what is the
>> distribution of "Rg"?
>> You could add another panel plot with Fig.3 to show Rg distribution
>> (Similar to Zg distribution).
>>
>> It is important to show for different "Delta_M/M" regions later
>> splitting dominates by showing Rg distribution in this measurement.
>>
>> So you want to see the other axis projection on figure 2 then? it is
>> possible sure but isnt the information already available in the dM/M
>> vs Rg?
>>
>> 2. "Similar trend for higher pT range" ->Where do you get this
>> conclusion? There is only one pT range 20-30 GeV/c is shown. (Same
>> for Slide-5)
>> we have analyzed the other pT bins and maybe we can show it in the
>> appendix.
>>
>> 3. "Suggests how the amount of initial wide and soft emission …"
>> ->How do we know these are "wide angle" emission?
>> this is also an answer for the question below - the early splits are
>> defined via the definition of the formation time in QCD which is
>> inversely prop to angle and energy - taken from the splitting
>> functions.
>>
>> Slide07
>> " "Observed an anti-correlation between the amount of early-stage
>> radiation and the angular scale of a later-stage splitting, where a
>> large groomed jet radius indicates small or no branching prior to
>> the SoftDrop splitting "
>> This statement is not clear what exactly it says.
>>
>> I think this conclusion is coming from the statement (Slide-5) of
>> "the dM/M distributions anti-correlated with Rg"
>> Then it is not clear how do we know these are "early-stage
>> radiation" and "later-stage splitting".
>> More explanation or better paraphrase is needed to make it clear.
>>
>> "Agreement/disagreement with MC event generators (pending finalizing
>> systematic uncertainties)" -> Figures 1,2, and 3 show that MC event
>> generators are in agreement with the data. Is not that?
>> Then why "/disagreement"?
>>
>> Slide-11
>>
>> Are we going to include Jet M distribution as one of supplementary
>> figures?
>> If yes, then it is not clear why do we need this figure as
>> supplement material? Particularly "M vs Q".
>> It sounds like a bit arbitrary.
>> Could you explain here?
>>
>> Slide-18,19:
>>
>> It shows "hadronization" has biggest effect on the collinear drop.
>> Then how reliable is it to say about early and later splitting as we
>> mention in Slide 6-7?
>>
>> Thank you
>> Nihar
>>
>> On 2023-03-02 03:19, Nihar Sahoo via Star-hp-l wrote:
>> Hello Youqi,
>> Thank you for this paper proposal.
>> Yes, results and the physics conclusions look good to me.
>> We can move forward for the PWGC review and we will discuss with
>> Rongrong to find a date.
>> Cheers
>> Nihar
>> On 2023-03-01 21:40, Youqi Song via Star-hp-l wrote:
>> Hi conveners,
>> Here are the slides for the presentation yesterday where we updated
>> the paper proposal
>>
> https://drupal.star.bnl.gov/STAR/system/files/star_collab_meeting_022823_1.pdf.
>> We think we are ready to move to PWGC review and Barbara is also
>> happy
>> with us moving forward. Please let us know if you have any questions
>> or comments. Thank you!
>> Best,
>> Youqi, Raghav and Helen
>> On Thu, Feb 16, 2023 at 1:18 PM Youqi Song <youqi.song AT yale.edu>
>> wrote:
>> Hi HP conveners,
>> I would like to follow up on the paper proposal I presented at our
>> PWG meeting last week. I have updated my slides here
>>
> https://drupal.star.bnl.gov/STAR/system/files/paper_proposal_021023.pdf
>> based on the feedback I got from the meeting:
>> Slide 12 - I've made the conclusions in a bullet point form.
>> Hopefully this highlights our physics messages more crisply.
>> Slide 17 - I included an example of a large dM jet from a PYTHIA
>> event.
>> As mentioned last week, we have been talking to some theorists who
>> agreed to provide some predictions for the collinear jet mass. I am
>> also finalizing the systematic uncertainties so that we can arrive
>> at a more concrete comparison with the MC generators.
>> We would like to know if this analysis could be pushed to PWGC
>> review soon or if there is anything else that people would like us
>> to prepare for. Please let us know if you have any questions or
>> comments. Thanks!
>> Best,
>> Youqi
>> _______________________________________________
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>> Star-hp-l AT lists.bnl.gov
>> https://lists.bnl.gov/mailman/listinfo/star-hp-l
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