STAR HardProbes PWG

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

Hello Isaac,

Please find our responses inline.

New paper draft version-3: 
https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityPaper_v3.pdf
AN version-3: 
https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityAanalysisNote_V3.pdf

On 2024-06-28 05:49, Mooney, Isaac wrote:
> Hi Nihar,
>
> I have some comments on your responses, below. Note that all line
> numbers and figures refer to the previous version.
>
> Thanks!
> Isaac
>
> 170. I'm confused by this response. You're saying that somehow mixed
> events are improving the combinatorial jet yield? My understanding is
> that ME corrects *for* the contribution of combinatorial yield in the
> overall distribution. Please elucidate.

Sorry, we misunderstood your previous comment. You are right – it 
doesn’t make sense as written. Changed to “Correction for the 
combinatorial jet yield in central \AuAu\ collisions is carried out 
using mixed events (ME),…”

> 192. I disagree that the additional phrase "deconvolution of detector
> effects" would be unhelpful for a general reader, but it is a small
> point so it's your choice.
Our initial response was that we have no strong view on this change, 
except for a concern about the overall length of the text, and since you 
find this to be important we have added it: “This event-wise approximate 
correction is refined by the deconvolution of detector effects 
(``unfolding''), described below.”

> 230. Ah, thank you for doing this study and putting my concerns to
> rest. I agree with you that the effect is small.
Your comment was very helpful – forced us to think more carefully how to 
bring this point forward in a complete and fair way.

> 233. I'm satisfied with this rewording. Thanks for adding this -- I
> think it's a nice clarification.
>
> 328. Sorry for being dense, but I'm still not understanding your
> comment here. Do you mean the intention was to say there is a)
> negligible (/no) enhancement, *and* b) some non-zero suppression? If
> so, I think it should be modified in the text because I don't think
> this is how most people would read that. Why not "...exhibiting a
> striking yield enhancement at large deflection angle for large-radius
> jets, and suppression for small-radius jets."? Please let me know if
> I'm way off-base.
You are not off-base. We were focused on drawing a connection to the 
ALICE acoplanarity broadening result, in which large R (0.4, 0.5) is 
enhanced and R=0.2 is unmodified. But that’s not what we see here: large 
R is indeed enhanced but small R is suppressed. The result was a garbled 
description. We have taken your rewording but also changed the following 
sentence:

“…exhibiting a striking yield enhancement at large deflection angle for 
large--\rr\ jets, and suppression for small--\rr\ jets. A strong yield 
enhancement for large--\rr\ but not small--\rr\ recoil jets has also 
been observed at the LHC.”


> Analysis Note, Fig. 14. Thanks for addressing this point.
>
> Analysis Note, Fig. 23. I disagree. The approach I am familiar with is
> to judge the closure test on its own terms, with statistical
> uncertainties on the ratio. When the ratio is consistent within the
> standard error, this is 'good' closure. Of course the edges will
> always be fuzzy, but that is also true of your approach which uses the
> systematics as the benchmark -- e.g. is 0.1% outside of the systematic
> uncertainty 'bad'? 1%? ... The only thing that has changed is that the
> benchmark is now the systematic rather than the statistical
> uncertainty, so it is not true that it is the "only quantitative
> standard". You say that "Given the finite statistics of the data,
> which is mimicked in this test, some deviation from unity must occur",
> but that is precisely what the statistical uncertainty should cover,
> and in addition the non-closure here is in bins with good statistics.
> I'm still not convinced that this is the proper approach. If you have
> a reference which demonstrates the argument, I think that would be
> very helpful for me.

This approach has been used by previous STAR and ALICE jet quenching 
papers, among others.

Unfolding by its nature entails systematic uncertainty. If the response 
matrix were known precisely, with arbitrarily high statistical 
precision, it could simply be inverted numerically to multiply the 
smeared data, resulting in the precise corrected distribution. But this 
doesn’t work in practice: we need to use a regularized (truncated) 
inversion, which is basically an assumption of smoothness, to avoid 
statistical noise that would generate arbitrarily large variance in the 
inverted matrix and render the result of the multiplication 
uninterpretable. Another name for this: regularized unfolding. So 
unfolding is never purely statistical.

Then to rephrase your proposal: compare the results of unfolding only to 
the magnitude of systematic uncertainty due to regularization in order 
to gauge its success. This we think is not a good basis for rejecting an 
analysis – why elevate this systematic uncertainty above all others?

The only reasonable standard we think is to ask whether unfolding 
results in deviations from the truth that are larger than the known 
uncertainties in the problem, i.e. the total systematic uncertainty. If 
closure is much better than that then there is no point of concern; if 
it is larger then the solution should not be considered to be valid.

We do not see a meaningful alternative to this procedure.


> Analysis Note, Fig. 27. Thanks for addressing this point with the
> addition to Fig. 3 and Sec. 3.13 of the analysis note. I do share
> Rongrong's remaining confusion being discussed in the email list about
> the values obtained in the plot (Fig. 28) and the effect of low-yield
> bins on the comparisons, although I guess this can be addressed in the
> GPC.

Thank you
Nihar for PAs (Derek, Saskia, and Peter)


> > On Jun 24, 2024, at 14:08, Ma, Rongrong via Star-hp-l 
> > <star-hp-l AT lists.bnl.gov> wrote:
> >
> > Hello Nihar
> >
> > Thanks for adding Sec. 3.14. However, it is not clear to me why the 
> > limit (upper vs. lower) would change depending on whether the recoil 
> > jet yield in pp is larger or smaller than that in AA. I_AA is defined 
> > as Y_AA/Y_pp. As along as Y_pp is an upper limit, I think I_AA should 
> > be the lower limit no matter if it is larger or smaller than 1. Maybe 
> > I am missing something? Also, I feel the way you calculate the 95% CL 
> > for I_AA probably needs some updates. Taking the ratio of 95% upper 
> > limit for Y_pp to Y_AA+Err_AA would not give you I_AA with 95% CL. I 
> > think one needs to use the central values of Y_pp and Y_AA to obtain 
> > I_AA, and then calculate its 95% CL based on the uncertainties. If 
> > this is not possible, you probably need some ToyMC to convolute the 
> > probability distributions for Y_pp and Y_AA.
> >
> > For Fig. 28, I do not think the last bin matters since its yield is 
> > very very small. In any case, I am interested in your checks.
> >
> > Thanks.
> >
> > Best
> > Rongrong
> >
> > > On Jun 22, 2024, at 7:42 AM, Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> 
> > > wrote:
> > >
> > > Hello Rongrong.
> > >
> > > I have included the discussion of IAA upper and lower limit 
> > > calculation in Section 3.14.
> > > Please have a look at the updated AN: 
> > > https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityAanalysisNote_V2.pdf
> > >
> > > I left Fig28 as it is because I calculated total yield by considering 
> > > the last bin's mid point and by fitting the Y(dphi) for a consistency 
> > > check. But I will check that calculation again during GPC discussion 
> > > to update this fig, however I expect no big change).
> > >
> > > Thank you
> > > Nihar
> > >
> > >
> > >
> > >
> > > On 2024-06-21 23:46, Ma, Rongrong wrote:
> > > > Hello Nihar
> > > > I do not think the last bin would cause the different I_AA shown in
> > > > Fig. 28, since its yield is very very small compared to other dphi
> > > > bins. The other bins closer to pi dominate recoil jet yields in pp 
> > > > and
> > > > AA, and thus I_AA.
> > > > Yes, indeed we discussed about the upper and lower limits before.
> > > > Sorry, I forgot about the details. From your response, do you mean
> > > > "For upper limit case, we take upper bound AuAu and lower bound of 
> > > > pp
> > > > in IAA calculation"? I could not find any details in the AN.
> > > > THanks.
> > > > Best
> > > > Rongrong
> > > > > On Jun 21, 2024, at 1:42 PM, Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> 
> > > > > wrote:
> > > > > Hello Rongrong,
> > > > > Please find my replies inline.
> > > > > On 2024-06-21 19:03, Ma, Rongrong wrote:
> > > > > > Hello Nihar
> > > > > > Thanks for the numerical values. If I sum up the recoil jet yields 
> > > > > > for
> > > > > > pp and AA, here is what I get.
> > > > > > 1) pi0 trigger, R = 0.2, 10 < pT < 15 GeV/c
> > > > > > Y_AA = 0.030
> > > > > > Y_pp = 0.065 (the last bin with upper limit does not matter since 
> > > > > > its
> > > > > > yield is so much smaller than the other three dphi bins)
> > > > > > I_AA = Y_AA/Y_pp ~ 0.47
> > > > > > 1) pi0 trigger, R = 0.2, 15 < pT < 20 GeV/c
> > > > > > Y_AA = 0.012
> > > > > > Y_pp = 0.063
> > > > > > I_AA = Y_AA/Y_pp ~ 0.19
> > > > > > These I_AA values are consistent with Fig. 3 in the paper, but not
> > > > > > Fig. 28 in AN where you demonstrate the consistency. Could you 
> > > > > > double
> > > > > > check the procedure for getting Fig. 28?
> > > > > Thank you for this crosscheck.
> > > > > I have calculated considering that last bin's central value (but we 
> > > > > only show upper limit in fig.2) just to have a consistency check. 
> > > > > That could be the reason for Fig.28.
> > > > > > As I am looking at this in more detail, another question arises. 
> > > > > > For
> > > > > > pi0+jet measurements in p+p collisions, you have upper limits for 
> > > > > > the
> > > > > > dphi bin furthest to pi for both R = 0.2 and 0.5, which makes 
> > > > > > sense.
> > > > > > However, you have upper limits for I_AA for R = 0.5, and lower 
> > > > > > limits
> > > > > > for R = 0.2 jets. Why is this the case? How do you derive an upper
> > > > > > limit on I_AA given the upper limit on Y_pp?
> > > > > I remember, we had a discussion on this before if you recall.
> > > > > But let me reiterate that to you here again.
> > > > > For upper limit case, we take upper bound of pp and AuAu in IAA 
> > > > > calculation.
> > > > > similarly for lower bound, Lower limit of pp and AA.
> > > > > Thank you
> > > > > Nihar
> > > > > P.S. Coming two weeks I will be traveling so I may be slow in 
> > > > > replying.
> > > > > > Thanks.
> > > > > > Best
> > > > > > Rongrong
> > > > > > > On Jun 21, 2024, at 6:29 AM, Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> 
> > > > > > > wrote:
> > > > > > > Hello Rongrong,
> > > > > > > Please find the data points here.
> > > > > > > Upper bound of last bin is mentioned there separately.
> > > > > > > https://drupal.star.bnl.gov/STAR/blog/nihar/acoplanarity-pp-data
> > > > > > > Thank you
> > > > > > > Nihar
> > > > > > > On 2024-06-21 01:09, Ma, Rongrong wrote:
> > > > > > > > Hello Nihar
> > > > > > > > Thanks for the numbers. Could you also send out the recoil jet 
> > > > > > > > yields
> > > > > > > > in pp and AA collisions for the four dphi bins between 2.2 and 
> > > > > > > > 3.14,
> > > > > > > > as shown in Fig. 2 of the paper? Could you do the same for 10-15 
> > > > > > > > GeV/c
> > > > > > > > as well? Thanks.
> > > > > > > > Best
> > > > > > > > Rongrong
> > > > > > > > > On Jun 20, 2024, at 2:59 PM, Nihar Sahoo 
> > > > > > > > > <nihar AT rcf.rhic.bnl.gov> wrote:
> > > > > > > > > Hello Rongrong,
> > > > > > > > > As you mentioned this is a bit tricky to get exactly the same 
> > > > > > > > > yield for two cases due to dphi weights and also unequal total 
> > > > > > > > > dphi sum from Fig.2.
> > > > > > > > > But I tried to estimate the yield for one case (15-20 GeV/c and 
> > > > > > > > > R=0.2) and calculate IAA.
> > > > > > > > > Here is the value 3.14 to 2.2 rad.
> > > > > > > > > 0.0033 (AA) /0.0109(pp) = 0.302 (IAA from Dphi) that is close 
> > > > > > > > > to IAA(pT) ~0.3.
> > > > > > > > > I have not considered uncertainty calculation.
> > > > > > > > > Best
> > > > > > > > > Nihar
> > > > > > > > > On 2024-06-20 02:38, Ma, Rongrong wrote:
> > > > > > > > > > Hello Nihar
> > > > > > > > > > Thanks for updating Fig. 3 in the paper.
> > > > > > > > > > As you mentioned, different dPhi bins contribute differently 
> > > > > > > > > > to the
> > > > > > > > > > integrated recoil jet yields and I_AA for 2.35 < dphi < 3.14. 
> > > > > > > > > > However,
> > > > > > > > > > according to Fig. 2 of the paper, recoil jet yield drops 
> > > > > > > > > > exponentially
> > > > > > > > > > with decreasing dphi, so the new bins with upper limits that 
> > > > > > > > > > you just
> > > > > > > > > > added are furthest to dphi = 3.14, and thus contribute the 
> > > > > > > > > > least. It
> > > > > > > > > > is not clear to me how they can pull the integrated I_AA so
> > > > > > > > > > significantly. If possible, I suggest to directly compare 
> > > > > > > > > > recoil jet
> > > > > > > > > > yields for the two cases (vs. pt or vs. dphi). This can avoid 
> > > > > > > > > > the
> > > > > > > > > > complicated weighted average of I_AA.
> > > > > > > > > > Best
> > > > > > > > > > Rongrong
> > > > > > > > > > > On Jun 19, 2024, at 12:07 PM, Nihar Sahoo 
> > > > > > > > > > > <nihar AT rcf.rhic.bnl.gov> wrote:
> > > > > > > > > > > Hello Rongrong,
> > > > > > > > > > > Thank you for pointing this.
> > > > > > > > > > > A updated upper bound for R=0.2 of 15-20 GeV/c pi0+jet case 
> > > > > > > > > > > is included in paper Fig.3. (It was missed in previous draft 
> > > > > > > > > > > but now corrected)
> > > > > > > > > > > This one I checked it before.
> > > > > > > > > > > For pi0+jet 15-20 GeV/c R=0.2 case:
> > > > > > > > > > > As this is a differential measurement in Delta phi, each dphi 
> > > > > > > > > > > contributes differently.
> > > > > > > > > > > The last bin which is reported with upper bound is greater 
> > > > > > > > > > > than I_AA=0.3 (see revised Fig.3), hence this bin contributes 
> > > > > > > > > > > such that resultant integrated IAA(pTjet) value is around 0.3 
> > > > > > > > > > > (which is del_phi: 2.35 to 3.14 rad).
> > > > > > > > > > > The same scenario is for 10-15 GeV/c for R=0.2; where the 
> > > > > > > > > > > upper bound is lower than 0.3, and that contributes to 
> > > > > > > > > > > Integrated IAA(pTjet) value.
> > > > > > > > > > > The updated paper draft (same v2): 
> > > > > > > > > > > https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityPaper_v2.pdf
> > > > > > > > > > > Best
> > > > > > > > > > > Nihar
> > > > > > > > > > > On 2024-06-19 03:35, Ma, Rongrong wrote:
> > > > > > > > > > > > Hello Nihar
> > > > > > > > > > > > Thanks a lot for addressing my comments. Those plots for 
> > > > > > > > > > > > consistency
> > > > > > > > > > > > check in AN are very useful. However, it is not clear how 
> > > > > > > > > > > > you extract
> > > > > > > > > > > > the I_AA values from dPhi differential measurement. Do you 
> > > > > > > > > > > > use the
> > > > > > > > > > > > same dPhi range and same pp reference as in I_AA(pT) 
> > > > > > > > > > > > analysis? In the
> > > > > > > > > > > > lower panel of Fig. 28, integrated I_AA(dphi) ~ 0.3 for pi0 
> > > > > > > > > > > > triggers
> > > > > > > > > > > > and recoil R = 0.2 jets of 15 - 20 GeV/c. However, in Fig. 
> > > > > > > > > > > > 3, bottom
> > > > > > > > > > > > panel of the paper draft, I_AA values in all three dPhi bins 
> > > > > > > > > > > > are below
> > > > > > > > > > > > 0.3. Why? The same question goes to pi0 trigger, recoil R = 
> > > > > > > > > > > > 0.2 jets
> > > > > > > > > > > > of 10-15 GeV/c. The integrated I_AA value is about 0.3 in 
> > > > > > > > > > > > AN, but all
> > > > > > > > > > > > three I_AA(dphi) values are above 0.4 in the paper draft.
> > > > > > > > > > > > Best
> > > > > > > > > > > > Rongrong
> > > > > > > > > > > > > On Jun 18, 2024, at 4:25 AM, Nihar Sahoo via Star-hp-l 
> > > > > > > > > > > > > <star-hp-l AT lists.bnl.gov> wrote:
> > > > > > > > > > > > > Hello Rongrong, Yi , and Isaac,
> > > > > > > > > > > > > Thank you for your constructive comments.
> > > > > > > > > > > > > We have worked on your comments. Please find our responses 
> > > > > > > > > > > > > at one place:
> > > > > > > > > > > > > (Rongrong, Yi, and Isaac's comments are in order)
> > > > > > > > > > > > > https://drupal.star.bnl.gov/STAR/system/files/PWGComments_Acoplanarity_June16.pdf
> > > > > > > > > > > > > In this revised paper draft, Supplement material is 
> > > > > > > > > > > > > included.
> > > > > > > > > > > > > Revised paper draft 
> > > > > > > > > > > > > (v2):https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityPaper_v2.pdf
> > > > > > > > > > > > > Revised AN v2: 
> > > > > > > > > > > > > https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityAanalysisNote_V2_0.pdf
> > > > > > > > > > > > > We request HP-pwg converners to help us forming GPC.
> > > > > > > > > > > > > Best
> > > > > > > > > > > > > Nihar for PAs( Derek, Saskia, Peter)
> > > > > > > > > > > > > On 2024-05-06 12:55, Yi Yang wrote:
> > > > > > > > > > > > > > Hi Nihar,
> > > > > > > > > > > > > > Thanks a lot for the well-written draft and analysis note.
> > > > > > > > > > > > > > I agree with Rongrong's comments, so won't repeat here. I 
> > > > > > > > > > > > > > have some
> > > > > > > > > > > > > > minor ones for your consideration.
> > > > > > > > > > > > > > Paper draft:
> > > > > > > > > > > > > > - L36 - 38: the hyphens look a bit strange to me, it 
> > > > > > > > > > > > > > should look
> > > > > > > > > > > > > > like the one in L26.  (similar for L314 and 315)
> > > > > > > > > > > > > > - L41: high energy --> high-energy
> > > > > > > > > > > > > > - L58: pT, jet > 30 GeV/c
> > > > > > > > > > > > > > - L59: R=0.3 --> R = 0.3
> > > > > > > > > > > > > > - L116: Gev --> GeV
> > > > > > > > > > > > > > - Eq.(1) and (2): it should be d^2 N_jet and d^2 sigma
> > > > > > > > > > > > > > - L156: sqrt(s_NN)=200 GeV --> sqrt(s_NN) = 200 GeV
> > > > > > > > > > > > > > - Figure 1: I would suggest to put the information in the 
> > > > > > > > > > > > > > right
> > > > > > > > > > > > > > panel to the left panel as well, just in case someone cut 
> > > > > > > > > > > > > > the left
> > > > > > > > > > > > > > panel only and there is no information on that.
> > > > > > > > > > > > > > - L229: What does "TBD" mean here? Will this affect the 
> > > > > > > > > > > > > > final
> > > > > > > > > > > > > > physics conclusion?
> > > > > > > > > > > > > > - L245: Fig.2 --> Figure 2
> > > > > > > > > > > > > > Question: (I probably asked it earlier) you show different 
> > > > > > > > > > > > > > behavior
> > > > > > > > > > > > > > for R = 0.2 and 0.5, does it make sense to try other R 
> > > > > > > > > > > > > > numbers to see
> > > > > > > > > > > > > > the actual R-dependence?
> > > > > > > > > > > > > > Analysis note:
> > > > > > > > > > > > > > - L172: Figure 23 --> Figure 9?
> > > > > > > > > > > > > > - Question: you are using PYTHIA-8 in the 
> > > > > > > > > > > > > > embedding/simulation, but
> > > > > > > > > > > > > > you used PYTHIA-6 for the comparison in the result. Why 
> > > > > > > > > > > > > > not use the
> > > > > > > > > > > > > > same version of PYTHIA?
> > > > > > > > > > > > > > -  Don't you have the systematics from the unfolding 
> > > > > > > > > > > > > > iteration?
> > > > > > > > > > > > > > - Figure 23: It clearly shows the closure is not good 
> > > > > > > > > > > > > > between 2.5
> > > > > > > > > > > > > > and 3, and you are using log in the ratio. Any systematics 
> > > > > > > > > > > > > > associated
> > > > > > > > > > > > > > with it?
> > > > > > > > > > > > > > - L403, 404: there are "TBA"s, what does that mean?
> > > > > > > > > > > > > > - L435: The uncertainty on dPhi weights is "TBD"?
> > > > > > > > > > > > > > - Figure 26: do you have a similar plot for R = 0.2? What 
> > > > > > > > > > > > > > do the two
> > > > > > > > > > > > > > "light blue" lines mean here?
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > Yi
> > > > > > > > > > > > > > On Mon, Apr 8, 2024 at 10:16 AM Nihar Sahoo via Star-hp-l
> > > > > > > > > > > > > > <star-hp-l AT lists.bnl.gov> wrote:
> > > > > > > > > > > > > > > Hello HP-pwg,
> > > > > > > > > > > > > > > We have finalized STAR gamma+jet and pi0+jet acoplanarity 
> > > > > > > > > > > > > > > paper
> > > > > > > > > > > > > > > draft.
> > > > > > > > > > > > > > > Paper draft, analysis Note, and paper webpage can be 
> > > > > > > > > > > > > > > found below.
> > > > > > > > > > > > > > > Please send your comment and feedback.
> > > > > > > > > > > > > > > We request to form GPC.
> > > > > > > > > > > > > > > Paper draft:
> > > > > > > > > > > > > > https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityPaper_v1.pdf
> > > > > > > > > > > > > > > Analysis Note:
> > > > > > > > > > > > > > https://drupal.star.bnl.gov/STAR/system/files/AcoplanarityAanalysisNote_V0_0.pdf
> > > > > > > > > > > > > > > Paper webpage:
> > > > > > > > > > > > > > https://drupal.star.bnl.gov/STAR/blog/nihar/Paper-webpage-Measurement-direct-photonjet-and-pi0jet-azimuthal-correlation-AuAu-and-pp-c
> > > > > > > > > > > > > > > Thank you
> > > > > > > > > > > > > > > PAs (Nihar, Derek, Saskia, and Peter)
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