STAR HardProbes PWG

[Tong Liu <tong.liu AT yale.edu>]

Hi Sooraj & all,

Thanks for the signoff. Now that everyone has given the green light (Sooraj & Nihar spelled the buzzword, but Barbara and Yi also expressed they don't have further comments), can someone push my entry to star-talks, so that Rongrong can take a look on his side? The organizers of the conference explicitly instructed us to upload the slides by Monday since there won't be internet access at the venue. Thanks!

Tong Liu

Ph.D. Student '2023 

Physics Dept., Yale University

Tel: 203-435-2130

On Fri, Oct 7, 2022 at 9:11 AM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:

Hi Tong,

   Thanks for the replies, I dont have further comments and sign off

thanks

Sooraj

On Fri, Oct 7, 2022 at 12:26 AM Tong Liu via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi all,

Thank you all for the comments; let me reply inline. I've also uploaded the latest version of my slides onto drupal.

Sooraj:

S5: second sub-bullet, is that referring to the comparison between the isobar species?

Yes that's between Ru+Ru and Zr+Zr. 

S8: Where is the plot from? There has to be some label on the collision system and MC used

The plot is Ru+Ru Monte Carlo Glauber, I'll paste a textbox in the blank space; but it's actually generic to any heavy-ion system.

S8: What is N_hard^i(b_NN) in these equations?

It's the N_hard of each NN collision, and it's correlated to the b_NN of said binary collision.

S8: How does this effect impact the RAA calculations in central events with the Ncoll scaling from Glauber?

That's actually a good question! I thought about it for quite some time myself. The answer is, it does push the expected Raa higher than 1, but the effect is very small since the <Ncoll> in central collisions is much larger than peripheral ones and the absolute difference get diluted. 

S9: What is meant by synthetic PYHTHIA events?

This is what I said in slide 8, stacking all Ncoll PYTHIA event products together into one massive event.

S11: What do you mean by last sub-bullet? Isnt this already on slide 7+? What motivates this direction?

What I show in the slides is comparing Ru against Zr at same centrality percentage, yet we want to add another variation by comparing at same Npart (offset the percentage of each class by say ~1% but line up <Npart> of both species). The motivation here is to rule out the "size" difference as in Npart and really see whether there's difference from the nuclear structure and stuff. Admittedly the CME folks as well as deformation researchers are in a better position to study this phenomenon, but I can also take advantage of an updated centrality classification and refine my analysis.

Barbara:

- s9: what do you mean by ""Nhard/Ncoll" in the first sub-bullet ? The last bullet on slide 8 says: "Use <Nhard>/<Nhard^p+p> instead of <Ncoll> in R_AA calculation

Here what I actually show is <Nhard>/<Nhard^p+p> divided by <Ncoll> of each centrality class. I was thinking since <Nhard^p+p> is just one fixed number I'll use Nhard/Ncoll, but now that I have updated slide 8, I agree it's better to use consistent symbols.

Tong Liu

Ph.D. Student '2023 

Physics Dept., Yale University

Tel: 203-435-2130

On Thu, Oct 6, 2022 at 1:22 PM Yi Yang <yiyang0429 AT gmail.com> wrote:

Hi Tong,

Thanks a lot for the reply and the updated version. 

These slides look very nice and I don't have any further comments.

Cheers,

Yi

On Thu, Oct 6, 2022 at 11:58 AM Tong Liu <tong.liu AT yale.edu> wrote:

Hi all,

I just posted my latest draft version to drupal. Please take a look.

Tong Liu

Ph.D. Student '2023 

Physics Dept., Yale University

Tel: 203-435-2130

On Wed, Oct 5, 2022 at 5:49 PM Tong Liu <tong.liu AT yale.edu> wrote:

Hi all,

Thanks for the comments; please find my responses to some of the points below.

I just did a rehearsal at Yale a few hours ago, and I have got some comments there as well. I'll update my slides ASAP once I addressed those comments.

Cheers,

Tong Liu

Ph.D. Student '2023 

Physics Dept., Yale University

Tel: 203-435-2130

Nihar:

Slide13:

I think it would be good if you could put some texts mentioning the

reason for the shrinking of the uncertainty band compared to QM2022 and

also results up to smaller <Npart>. What do you think?

I don’t think it’s a good idea, since the updated version is clearly a more correct and accurate one, and that’s the message we want to leave people with. The QM version is what it is out of the box, but physically speaking we clearly should use the current 42 mb simulation, and now that we have the right version I don’t think we should mention the earlier one. That being said, I’d be happy to put something in backup, so that if somebody asks we can have something prepared.

Slide14:

_ "More input needed in the next week" do you want to update anything?

I was planning to, but I don’t think I will be able to. I was planning on another simulation, which was cutting it very close already, then the Yale cluster was down the whole day yesterday; I’m going to leave it till afterwards. This physics message should already suffice.

Barbara:

- s15: the blue text is not so well visible on the green background.

Yeah I’m not very happy about that either… but now that I just did a rehearsal at Yale and I’m over time, I kinda want to lose this slide altogether since it was supposed to be a transition slide between my talk and the other low-pt spectrum talk back at QM.

 

Yi:

p5: Could you please tell me why there are many repeated lines for Ru+Ru and Zr+Zr collisions on the right plot? What does that mean, just for my own education?

That’s to stress the point that we are alternating between Ru and Zr collision on a run-by-run bases, instead of running Ru for half the time and then switch to Zr for the remaining half. I’ll make it more clear in the text.

p6: Could you please remind me why there is a drop at 7 GeV on both collisions? 

That’s because the p+p collision was larger than it’s supposed to be at the range. Statistical fluctuations.

p8, p9: What is this blue box for? 

That one is just to guide the eye where I want to temporarily block the low pt region and let people focus on the high pt. It was a solid block until Nihar asked me to make it transparent, but now it looks like I’m trying to highlight it instead of blocking it… 

p13: Could you please remind me what Y^ch_pT is? 

Here I treat the synthetic PYTHIA events as real events and calculate its Raa. In the Yale rehearsal people have suggested to take the pT>5GeV part off since it’s in the text anyway

 

On Wed, Oct 5, 2022 at 1:14 PM Yi Yang via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi Tong,

Thanks a lot for the very nice slides. I have some minor comments/suggestions for your consideration. 

p3: the RAA formula, is it possible to let "RAA" to be in the same line with the rest? 

p5: Could you please tell me why there are many repeated lines for Ru+Ru and Zr+Zr collisions on the right plot? What does that mean, just for my own education?

p6: Could you please remind me why there is a drop at 7 GeV on both collisions? 

p8, p9: What is this blue box for?  

p13: Could you please remind me what Y^ch_pT is? 

p15: The last bullet in blue is a bit difficult to read, is it possible to change to another color? 

 

Cheers,

Yi

On Wed, Oct 5, 2022 at 10:32 PM Barbara Trzeciak via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi Tong, 

very nice slides, please find my additional comments below. WIth these addressed I sign off.

Cheers,

Barbara

- s6: if p+p uncertainties are not preliminary, please add references (we often do this on the plot itself  e.g."pp uncertainty, PRL 91, 172302 (2003)")

- s11-13: somewhere there you should explain what is "HF-PYTHIA N_hard" and "HF-PYTHIA Y_pT^ch > 5 GeV/c" (what's the difference between them).

- s14: same question as Nihar, are you still planning on adding something here ? I would suggest not to add too much of the last moment studies.

- s15: the blue text is not so well visible on the green background.

On Wed, Oct 5, 2022 at 2:31 PM Nihar Sahoo via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi Tong,

As discussed yesterday, probably we need to be careful not to change
again these Model calculations in our preliminary plots. So I would
suggest crosschecking and confirming again from your side on this model
calculation to show at HQ2022.

Besides, I have the following comments on your last updated presentation
slides (_1003.pdf).

Slide11:
NN -> Nucleon-Nucleon (NN)
What is b_NN? You need to describe it.

Slide13:
I think it would be good if you could put some texts mentioning the
reason for the shrinking of the uncertainty band compared to QM2022 and
also results up to smaller <Npart>. What do you think?

Slide14:
_ what is "nMPI"? Do you need to mention it somewhere?
_ "More input needed in the next week" do you want to update anything?


Thank you
Nihar





On 2022-10-04 06:11, Tong Liu wrote:
> HI Nihar,
>
> I uploaded a new version of the slides, please take a look. As for the
> pt range in previous results, I decided to do some "subtraction"
> instead of "addition" by removing the word "isobar" from the text on
> figure, so that it looks more like I'm referring to everyone. Please
> let me know what you think about it. Also I'll try to push on the
> pythia MPI side, but I'm not very sure I'll be able to get anywhere
> significant beyond where I am now. Let's assume this is the message we
> are going to give, and I'll let you know if I dig up something.
>
> Tong Liu
> Ph.D. Student '2023
> Physics Dept., Yale University
>
> Tel: 203-435-2130
>
> On Mon, Oct 3, 2022 at 9:07 AM Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>
> wrote:
>
>> Hi Tong,
>>
>> Please find my reply inline.
>> And looking forward to seeing your updated presentation slides.
>>
>> On 2022-10-02 07:43, Tong Liu wrote:
>>> Hi Nihar,
>>>
>>> Thanks for your comments. Please find my responses below-- those
>> not
>>> mentioned are applied to my slides already. However I'd like to
>> take
>>> until Sunday night and hopefully make some more changes to them
>> before
>>> uploading again, since we already have a lot to discuss here.
>>>
>>> Title: good catch; I meant “high-pt”. One of the worst places
>> to
>>> have a typo :p
>>> Slide#3:
>>>
>>> _Do you want to say something about right side plots? Any link to
>> your
>>>
>>> analysis…please point out that.
>>> Here it’s just an introduction to high pt hadron as a proxy to
>> jet
>>> quenching effect. The plot I used is the Au+Au high-pt hadron Raa,
>>> which is going to be used later as well; in the text I was really
>>> trying to be general and not talk about any specific measurement,
>> but
>>> I might talk about it orally. If you think it’s too much though
>> I
>>> can take it off; but I’d say let’s wait till a first
>> rehearsal.
>>
>> OK. that's fine.
>>
>>> Also it might be a good idea to put this slide right after the
>> title
>>> slide?
>>> Slide#4:
>>>
>>> STAR TPC eta acceptance is |eta| < 1.4 (without iTPC)
>>>
>>> What acceptance you are quoting here?
>>> I'm pretty sure it's |eta|<1… Please see slide 4 in
>>>
>>
> https://indico.cern.ch/event/689846/contributions/2947105/attachments/1635225/2608617/Yichang-ChiYang.pdf
>>> [1]
>>> Slide#6
>>>
>>> _Can you please remind me where do you get this "p+p uncertainty"?
>>>
>>> That comes from this paper:STAR Phys. Rev. Lett. 91, 172302 (2003)
>>> Slide#10:
>>>
>>> It is important to mention for Au+Au, d+Au, and Cu+Cu, what pT
>> ranges
>>>
>>> were used?
>>>
>>> It’s also using 5.1-10 GeV, same as isobar. The statement at the
>>> bottom of the graph was meant for all measurements, but apparently
>> it
>>> was not clear enough. Any suggestions?
>>
>> I would add one bullet mentioning this.
>>
>>> Slide#12:
>>>
>>> _ you have now two models: I) HG-PYTHIA QM2022 preliminary and II)
>> new
>>>
>>> results that you labeled as "X+X N_hard"
>>>
>>> AFAIK, the difference between I) and II) is due to choice of
>> N_hard
>>> and
>>>
>>> N_part . Is not that?
>>>
>>> But from your labels it seems for I) you used pT>5 GeV, and for
>> II)
>>>
>>> N_hard is used but all pT range.
>>>
>>> Is that true?
>>> _ Why your uncertainty band for I) QM2022 preliminary results has
>> been
>>>
>>> changed? It looks wider band in your preliminary results.
>>> OK let me explain further here… what the HG-PYTHIA model does
>> is, it
>>> generates a Glauber-level collision, throw a Poisson dice and
>>> determine how many hard collisions each NN collision has (Nhard).
>> Then
>>> it goes to PYTHIA and ask for a p+p collision with nMPI=Nhard
>> (yeah
>>> that part I don’t understand yet either); then all the tracks
>> from
>>> all the PYTHIA collisions are stacked together to be the synthetic
>>> event. Here in the plot, both options categorized events into
>>> centralities with the “refmult” of this synthetic event, but
>> the
>>> “benchmark values” are calculated in different ways: in the
>>> “Nhard” option, the average Nhard in each centrality class is
>>> compared to <Nhard> of pp collisions, while in the “Y_ch”
>> option,
>>> the invariant yield of 5 GeV+ tracks is used (<Ncoll> scaling is
>>> applied in both cases, of course). I didn’t use any <N_part> in
>> this
>>> baseline beyond the x axis.
>>> As for the change to QM prelim, that one  was easy: I squeezed
>> much
>>> larger statistics out of the simulation. In fact this one is still
>>> statistical error only, and I’ll try to get a crude systematics
>> in
>>> the next week.
>>
>> Ok, I got it some extent now.
>>
>> Thank you
>> Nihar
>>>
>>> Slide#14:
>>>
>>> Do you have associated systematic uncertainty for <Ncoll> and
>> <Npart>
>>>
>>> scaled?
>>>
>>> The systematic uncertainty assigned to <Ncoll> and <Npart> by the
>>> centrality group is VERY small, and I suspect they are correlated
>>> between species, so they also largely cancel out.
>>>
>>> Tong Liu
>>> Ph.D. Student '2023
>>> Physics Dept., Yale University
>>>
>>> Tel: 203-435-2130
>>>
>>> On Sat, Oct 1, 2022 at 3:03 AM Nihar Sahoo via Star-hp-l
>>> <star-hp-l AT lists.bnl.gov> wrote:
>>>
>>>> Hello Tong,
>>>>
>>>> Please find my comments below  on your nice presentation slides.
>>>>
>>>> Slide#1:
>>>> Title: System size dependence of pT hadron yield modification…"
>>>> ->
>>>> "System size dependence of hadron yield suppression…" or
>> something
>>>> like
>>>> that
>>>> Here, "pT hadron yield modification" sounds awkward.
>>>>
>>>> Slide#3:
>>>> _Title: "…QGP probe" -> "…QGP Probe"
>>>> _"..lose energy to QGP" -> "… lose energy in QGP"
>>>> _"…RAA: comparison to p+p collisions" -> not quite right?
>> Define
>>>> RAA
>>>> using Au+Au and nuclear thickness function..
>>>> It is important for your previous bullet for Npart and Ncoll
>>>> _Do you want to say something about right side plots? Any link to
>>>> your
>>>> analysis…please point out that.
>>>>
>>>> Slide#4:
>>>> STAR TPC eta acceptance is |eta| < 1.4 (without iTPC)
>>>> What acceptance you are quoting here?
>>>>
>>>> Slide#6
>>>> _Can you please remind me where do you get this "p+p
>> uncertainty"?
>>>>
>>>> Slide#8-9
>>>> I would make that blue box transparent such that the data points
>> can
>>>> be
>>>> visible behind.
>>>>
>>>> Slide#10:
>>>> It is important to mention for Au+Au, d+Au, and Cu+Cu, what pT
>>>> ranges
>>>> were used?
>>>>
>>>> Slide#12:
>>>>
>>>> _ you have now two models: I) HG-PYTHIA QM2022 preliminary and
>> II)
>>>> new
>>>> results that you labeled as "X+X N_hard"
>>>> AFAIK, the difference between I) and II) is due to choice of
>> N_hard
>>>> and
>>>> N_part . Is not that?
>>>> But from your labels it seems for I) you used pT>5 GeV, and for
>> II)
>>>> N_hard is used but all pT range.
>>>> Is that true?
>>>>
>>>> _ Why your uncertainty band for I) QM2022 preliminary results has
>>>> been
>>>> changed? It looks wider band in your preliminary results.
>>>>
>>>> Slide#14:
>>>> Do you have associated systematic uncertainty for <Ncoll> and
>>>> <Npart>
>>>> scaled?
>>>>
>>>> Cheers
>>>> Nihar
>>>>
>>>> On 2022-09-29 09:54, webmaster--- via Star-hp-l wrote:
>>>>> Dear Star-hp-l AT lists.bnl.gov members,
>>>>>
>>>>> Tong Liu (tong.liu AT yale.edu) has submitted a material for a
>>>> review,
>>>>> please
>>>>> have a look:
>>>>> https://drupal.star.bnl.gov/STAR/node/61208
>>>>>
>>>>> Deadline: 2022-10-11
>>>>> ---
>>>>> If you have any problems with the review process, please contact
>>>>> webmaster AT www.star.bnl.gov
>>>>> _______________________________________________
>>>>> Star-hp-l mailing list
>>>>> Star-hp-l AT lists.bnl.gov
>>>>> https://lists.bnl.gov/mailman/listinfo/star-hp-l
>>>> _______________________________________________
>>>> Star-hp-l mailing list
>>>> Star-hp-l AT lists.bnl.gov
>>>> https://lists.bnl.gov/mailman/listinfo/star-hp-l
>>>
>>>
>>> Links:
>>> ------
>>> [1]
>>>
>>
> https://indico.cern.ch/event/689846/contributions/2947105/attachments/1635225/2608617/Yichang-ChiYang.pdf
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--

Sooraj Radhakrishnan

Research Scientist,

Department of Physics

Kent State University

Kent, OH 44243

Physicist Postdoctoral Affiliate

Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road

Berkeley, CA 94720

Ph: 510-495-2473

Email: skradhakrishnan AT lbl.gov