STAR HardProbes PWG

[Rosi Reed <rosijreed AT lehigh.edu>]

Hi Nihar,

A few comments-

> My overall suggestion on Tristan's presentation is that due to limited
> time, let's only focus on the observation from this preliminary results.

I agree that the time is limited so further analysis is not possible, but I would disagree that it is too limited to think about the interpretation of the result.  I would even venture to say that most of our thinking as a collaboration for what the results mean happen in the week or two before a conference presentation because this is when results are nailed down and people realize they need to say something about them.

> Sorry, I still don't understand your argument here.
> We don't have very good information about jet RAA/RCP in "isobar"
> collision mainly kinematic range in pT etc. I know we have BES RCP which
> is in Au+Au collision.
> Here the system size is smaller compared to Au+AU.
> Unless we measure Jet RAA/RCP in Isobar we should not make any
> conclusion/statement based on what we know from Au+Au measurement.

Actually - Tong is presenting the high pT hadron RAA in the isobars at this very conference, which extends into the pT range of the jets.  So we know that the RAA will be ~0.6-0.7 for the kinematic range that Tristan is reporting.  An RAA of less than 1 indicates quenching, and if there is quenching there must be a surface bias.  So I don't think it's fair to say that we don't have good information about the jet RAA as high pT hadrons have always been considered a good proxy for jets.

Yes, Isobars are smaller than Au+Au, but there is actually a fair amount of data on even smaller systems out there.  For example, we know that the RAA < 1 for Cu+Cu published by STAR in https://arxiv.org/pdf/0911.3130.pdf.  There are a number of results out of PHENIX as well.  Just as Zr/Rb is ~1/2 of Au, Cu is ~1/2 of Zr/Rb.

I think that it is well established that there is quenching in these smaller systems - what we're working out now is quantifying the details.

> We can't say anything more on "jet modification is path-length
> dependent" in Isobar collisions; simply because in this measurement we
> have not done any jet modification study.

The jet v2 IS a jet modification study. If jets were not modified, the v2 would be nearly zero.

>For that we need to explicitly perform jet suppression study for this
> system.

With Tong's charged hadron RAA, I think this has been explicitly measured.  However, I would push back here - the very first jet quenching measurements were done long before we measured high pT RAA.  This is one analysis, and while I would agree that it is useful for a full understanding of jet quenching in a given system, it's certainly not required.  For that matter, we only published our first jet RAA paper last year.....

> A further study is warranted to comment on path-length dependent jet
> modification which we can discuss after HQ.

I completely disagree.  We can make a statement that we see path-length dependent modification based on this single measurement.  We can't say whether it is dominated by radiative or collisional energy loss, whether MPI effects are larger than LPM effects, what the surface bias is, etc. There's a lot we can't say - but this statement is an incredibly low bar in terms of interpreting the data.

> As I mentioned above, we have not done any Aj measurement in this small
> system Isobar collisions.
> And we do not have enough time to have this discussion before HQ which
> we can discuss after the conf.
> Using same process/cuts may not imply the jets we find are also surfaced
> biased in small system, for this concern we can discuss in details
> later.

I agree we have not done AJ measurements.  I disagree that the AJ measurement is necessary to state anything about surface bias. AJ as an observable was only invented in 2010 after the start of the LHC runs simply because there was not sufficient theory to compare the new LHC HI jet results to.  The discussions over the surface bias of hard probes date from at least the early 90s.  So we're simply stating a fact, especially in light of Tong's results, that quenching causes a surface bias.  Precisely how much it is, how it compares to Au+Au, and so forth, we don't comment on and can not at this time. 

Now, I completely agree that the selections from Au+Au may not map directly onto the Isobars - there is a lot of post-HQ work to do here.  We should repeat Nick's very nice differential checks with the v2.  I think we can also at least for internal consumption create a raw Aj measurement to compare to Kolja/Nick's results that can allow us to make additional comments.

I really don't think we're pushing the boundaries on what can be said here with this measurement, these are incredibly safe statements.

Regards,

Rosi

On Sun, Oct 9, 2022 at 12:02 PM Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> wrote:

Hello Rosi,

Thank you for your reply.
My overall suggestion on Tristan's presentation is that due to limited
time, let's only focus on the observation from this preliminary results.
for Any physics conclusion we need time to understand and discuss for
that we don't have time now.

Please find my response inline.

On 2022-10-09 20:09, Rosi Reed wrote:
> Hi Nihar,
> Just a few comments here:
>> 1. You don't need to put description of "ALCIE sys bands like
> correlated
>> and uncorrelated etc" One green circle is enough to represent ALICE
>> results.
> I think it's better to keep their descriptions here - otherwise it is
> STAR telling ALICE what their data should look like.  The correlated
> vs uncorrelated is important for making a statement about the
> comparison, if everything was uncorrelated the significance of the
> apparent agreement is much stronger, so I would be worried that by
> changing their results we would be misleading our audience a little on
> this very interesting result.

That is fine and it is just PAs choice.

>
>> Can you please elaborate how we draw the conclusion of " jet
>> modification is path-length dependent" in Isobar ?
>> We don't have any hard-core jet RAA/RCP measurement in isobar. Do we
>> have?
>
> We don't have RAA/RCP, but I don't see why this is necessary for the
> statement, we know that jet RAA will < 1 in the isobar system due to
> other measurements made by STAR (and PHENIX).  You could have a
> path-length dependent modification that averages out to precisely RAA
> = 1, though that would be unlikely in a collision with a center of
> mass energy greater than ~40 GeV judging by the RCP measurement made
> by Stephen from the BES data.  With a signal at 3.5 sigma, we can
> state that there is evidence for non-zero jet v2 at RHIC.  There must
> be some geometrical physics process causing this - if there was not,
> then the v2 would be close to zero.  In the paradigm of heavy ion
> collisions we have a choice of initial state effects (so some MPI),
> pressure gradients and path-length dependent suppression (i.e LPM
> effect).  We know we can exclude the middle term due to the high Q^2
> and the QGP formation time.  There is no evidence for the former term
> as of yet, so within the paradigm of jets in heavy ion collisions the
> latter is the assumption for the interpretation of the data that
> remains.  I certainly don't think we can overturn a decades long
> paradigm on the basis of a single statistics hungry measurement.
>

Sorry, I still don't understand your argument here.
We don't have very good information about jet RAA/RCP in "isobar"
collision mainly kinematic range in pT etc. I know we have BES RCP which
is in Au+Au collision.
Here the system size is smaller compared to Au+AU.
Unless we measure Jet RAA/RCP in Isobar we should not make any
conclusion/statement based on what we know from Au+Au measurement.

But it is fine for me with the statement "there is evidence for non-zero
jet v2 at RHIC in Isobar collision."
We can't say anything more on "jet modification is path-length
dependent" in Isobar collisions; simply because in this measurement we
have not done any jet modification study.
For that we need to explicitly perform jet suppression study for this
system.

So I suggest to remove "Suggests that jet modification is path-length
dependent, even in medium sized systems!" on slide#18.
and replacing  this "there is evidence for non-zero jet v2 at RHIC in
Isobar collision." is very important conclusion here which is apparent
from the figure.
A further study is warranted to comment on path-length dependent jet
modification which we can discuss after HQ.

>> I would be careful on this statement, as I mentioned we have not
> done
>> any dijet Aj study in Isobar to support of the surfaced bias jet
>> selection. It could be correct but we have not done any measurement
> so
>> we should abstain mentioning this.
>
> I don't believe that we have to measure AJ to state this basic fact of
> nuclear physics.  The surface bias of selecting hard fragmentation has
> been discussed since the earliest papers on jet quenching
> (https://physics.fjfi.cvut.cz/files/predmety/02RQGP/zs1617/GyulassyPluemer.pdf
> [1] for example), and has been mentioned many times by STAR itself in
> a variety of high pt and jet based measurements.  In fact, not
> mentioning it after STAR spent so much time discussing jet geometry
> evolution in the earlier AJ measurements would actually be akin to
> walking back our earlier statements since we're using the same process
> in this measurement.
>
As I mentioned above, we have not done any Aj measurement in this small
system Isobar collisions.
And we do not have enough time to have this discussion before HQ which
we can discuss after the conf.
Using same process/cuts may not imply the jets we find are also surfaced
biased in small system, for this concern we can discuss in details
later.

> I have also made some comments on Tristan's talk that he'll follow up
> on, and the official practice of his talk before the council member
> will happen on Monday so there will be a little bit of tweaking, even
> after he submits a draft v5.  One quick point on the uncertainties,
> Rongrong was quite correct in the meeting on Thursday that the
> uncertainty on the tracking efficiency only plays a role in the
> uncertainty if we're unfolding.  So there are no further effects that
> will change the systematics for this non-unfolded measurement - rather
> we're waiting on this as a last cross-check.

Looking forward to seeing Tristan's updated version.

Cheers
Nihar
>
> Cheers,
> Rosi
>
> On Sun, Oct 9, 2022 at 4:14 AM Nihar Sahoo via Star-hp-l
> <star-hp-l AT lists.bnl.gov> wrote:
>
>> Hello Tristan,
>>
>> Thank you for implementing my comments and your reply.
>> Please find my further comments and reply to your response.
>> All my comments on your recent version (v4).
>> Please don't remove your old version; that can be done after
>> finishing
>> our discussion otherwise it is difficult to follow the slide numbers
>>
>> with new version.
>>
>> 1) Have you updated your remaining sys uncertainty that we were
>> waiting
>> for?
>>
>> 2)Comments on Figures:
>> Slide18 fig:
>> 1. You don't need to put description of "ALCIE sys bands like
>> correlated
>> and uncorrelated etc" One green circle is enough to represent ALICE
>> results.
>> 2. Please include instead STAR sys box's description  in legend
>>
>> Slide17 fig:
>> _ Can you include v2 value (with uncertainty) in this figure that
>> you
>> get from the fitting?
>>
>> 3) Additional comment:
>> I think EPD is used for the first time in jet v2 measurement.
>> It would be good to include EP resolution plot that you get from
>> this
>> measurement.
>> For that you can combine slide15-16 to make a story for EPD and EP
>> calculation.
>>
>> 4) Slide18(in vesrion4):
>> "Suggests that jet modification is path-length dependent, even in
>> medium
>> sized systems!"
>> Can you please elaborate how we draw the conclusion of " jet
>> modification is path-length dependent" in Isobar ?
>> We don't have any hard-core jet RAA/RCP measurement in isobar. Do we
>>
>> have?
>>
>> We can only say so far (from this preliminary study) what you have
>> mentioned in conclusion slide19 (with slight modification "hint…")
>> "Hint of non-zero v2^ch jet is observed in a medium sized system "
>>
>> Please bring this statement in slide18
>>
>> 5) Slide19(v4 version)
>> _"A very different system!" -> "A very different kinematic range and
>>
>> system size"
>> _"v2ch jet is observed despite the introduced surface bias" -> "v2ch
>> jet
>> is observed despite the possible surface bias"
>> I would be careful on this statement, as I mentioned we have not
>> done
>> any dijet Aj study in Isobar to support of the surfaced bias jet
>> selection. It could be correct but we have not done any measurement
>> so
>> we should abstain mentioning this.
>> If you want, then need to do Aj measurement for this hard core jet
>> selection in Isobar.
>>
>> _"Our picture of jet quenching is not complete - there is still much
>> to
>> discover"
>> Sounds a vague statement. Please mention 1) what is not
>> completed
>> relating to jet quenching? 2) what do you think that needs to be
>> discovered?  Please elaborate this.
>>
>> Remaining reply can be found inline.
>>
>> On 2022-10-09 07:56, Tristan Protzman via Star-hp-l wrote:
>>> Hello Nihar,
>>>
>>> A new draft has been uploaded to Drupal.
>>>
>>> Note: it should be written as $p$+$p$ and $p$+Au, etc, which is
>>> different from the guidance.
>>>
>>> Fixed.
>>>
>>> Slide:2
>>> _Second bullet seems out of context here. Coupling is large at low
>> Q^2
>>> then why  is it relevant for the QGP and your jet anisotropy
>>> measurements? This part is not clear here.
>>> It motivates the need for a perturbative object like jets to probe
>>> what we actually want to study, the QGP.  Changed text to clarify.
>>
>> Still it is not clear and confusing for 1st and 3rd bullets.
>> If you want to motivate jet (which pQCD calculable) and this is used
>> to
>> probe QGP (which is asymptotic region of coupling); then what is the
>>
>> point to mention "alpha_s ~ O(1) at low Q^2."
>> I would suggest to rephrase;
>> "Since running coupling is asymptotically small at high Q^2,  pQCD
>> calculable probes are used to study the QGP medium"
>> Then you don't need 3rd bullet.
>>
>>>
>>> _ Give reference to the running coupling plot. And you could
>> replace
>>> with most updated version where LHC measurements (very highQ2
>> region)
>>> are included if you want to start with it.
>>> Changed.
>>>
>>> __GIve a reference or credit for left cartoon._
>>>
>>> Figure removed, I felt it did not add to the message.
>>>
>>> Slide:4
>>> _3rd bullet: "Leads to path length…"  this is not the only
>> effect;
>>> it
>>> could be various other contributions like color factor, Temp of
>> QGP,
>>> initial gluon density, etc. But you need to mention Your
>> motivation is
>>> to study "path length dependence".
>>> __ same comment for 4th bullet_
>>> I have adjusted this section to clarify that the aspect of jet
>>> modification I am trying to study is the path length dependent
>> nature
>>> of jet energy loss
>>>
>> Slide4 (current  v4)
>> _ "We are interested in understanding the path-length dependence of
>> these processes" -> "We are interested in understanding the
>> path-length
>> dependence of jet quenching"
>>
>> _"Both collisional and radiative" -> "Both collisional and radiative
>>
>> energy loss" or "Parton energy loss via both collisional and
>> radiative
>> processes"
>>
>>> _ 5th Bullet ("Both collisional and radiative") you need to
>> provide
>>> reference to the theory calculation for this L/L^2 dependence.
>> These
>>> are
>>> model calculations.
>>>
>> Slide4 (current v4)
>> _"Both collisional and radiative" -> "Both collisional and radiative
>>
>> energy loss" or "Parton energy loss via both collisional and
>> radiative
>> processes"
>>
>>>
>>> Removed L/L^2 statements as I am not comparing to any models in
>> this
>>> presentation
>>>
>>> _ This slide only focus on jet and jet quenching, but it doesn't
>>> motivate your measurement like why jet anisotropy measurement is
>>> required? Need to include some text on it.
>>> I suggest you need to motivate jet anisotropy before you go to any
>> jet
>>> analysis details like in Slide5  underlying event discussion
>>>
>>> The way I have structured my talk is to first motivate that we
>> have
>>> observed jet quenching.  I am using the dijet analysis to this
>> end.  I
>>> then want to contrast that with azimuthal anisotropy, which is not
>> a
>>> dissimilar measurement in that it probes jet modification, but it
>> does
>>> so in a new way.  Therefore, I think it makes sense to talk about
>> jet
>>> measurements and then the dijet measurement before introducing the
>>> idea of anisotropy and motivating how that can get us towards the
>>> missing path length dependence of a dijet analysis.
>>>
>>> SLide:5
>>> _Not clear, what is that right side plot? Is this data or MC
>>> simulation.
>>> What is pT, of track or jet? What is Delta phi?
>>> I agree, this plot was not particularly clear.  I have removed it.
>>> __"Soft processes produce a fluctuating background" what is that_
>>> _background? Is it track or _combinatoric_ jet background?_
>>> I'm not quite sure I understand what you are asking, it is the
>> tracks
>>> from soft processes which produce the combinatorial jet
>> background, so
>>> I suppose both?
>> Then it would good to mention, "Soft processes produce a fluctuating
>>
>> uncorrelated background for jet measurement in heavy-ion collisions"
>> Here "uncorrelated" is important.
>>
>> Slide5 (current v4), right figure is from STAR data or any model? No
>>
>> description mentioned there.
>>
>>> __3rd _bulltet_ (Estimated…) it should _be sub-bullet_ of 2nd
>> bullet
>>> (Soft_
>>> _process…)_
>>> Changed.
>>> __ what is kT?_
>>> The k_T jet finding algorithm, clarified.
>>> __ Jet area -> Jet area(A)_
>>>
>>> Changed.
>>>
>>> Slide6:
>>> _Not clear, what is that right side plot? Is this data or MC
>>> simulation?
>>> What is pT, eta, and phi?
>>> This is the total track momentum for eta/phi bins for a collision.
>>> __"A jet finder… had scattering and other processes" ->" had
>>> scattering_
>>> _and combinatorial background in heavy-ion collisions"_
>>> _2nd bullet is not required if you mention above.
>>>
>>> _ _I have merged this with slide 5 and changed this wording
>>>
>>> SLide:7
>>> I would suggest to use jet pT as $p_{\rm T, jet}$ throughout your
>>> presentation.
>>> Changed.
>>> __Used in other STAR analysis -> Proved references_
>>> __Provide _referecen_ to ALICE measurement_
>>>
>>> Done.
>>>
>>> Slide:8
>>> _Move this slide or Isobar jet pT distribution after your slide14
>>> where
>>> you discuss about Isobar dataset. It seems the left side plot just
>>> pop-up. This plot should be part of you results discussion even if
>> it
>>> is
>>> a STAR performance plot.
>>> Figure removed
>>> __"Statistically unlikely for soft processes…" Please rephrase
>>> this… not_
>>> _clear._
>>> Changed to clarify that it is unlikely for soft processes to
>> produce
>>> high pt hadrons which look like jets
>>> __"May bias jet selection towards surface" Not sure the motivation
>> of_
>>> _this bullet. _why it is_ important? You are not doing jet RAA/RCP
>>> study_
>>> _and you do not study trigger jet v2 then why it is important if
>> this
>>> jet_
>>> _is trigger biased or not. These jets should be treated as
>> inclusive
>>> _jet_._
>>>
>>> Is it not important to understand the biases we introduce into our
>>> measurements?  By requiring the high pT hadrons the selected jets
>> are
>>> biased towards the surface of the QGP.  This is the motivation for
>> one
>>> of the items we would like to explore next in this analysis, the
>>> variation of the hard core threshold.
>>>
>>> Slide:9
>>> This slide is not relevant. You could put in Backup. (A
>> distraction)
>>>
>>> I disagree, the story I am hoping to tell with this talk is that
>> we
>>> saw signs of jet quenching with measurements like dijet imbalance,
>> but
>>> that it doesn't tell the complete story.  We can continue our
>>> understanding of jet quenching from dijet measurements to jet v2
>>> measurements.
>>
>> slide8(in v4)
>> _ we are doing inclusive hard-core jet v2 measurement here. Is not
>> it?
>> _I am not convinced to motivate with dijet measurement here. Are we
>> going to do any dijet measurement in isobar?
>> _Selecting a hard-core jet may not imply you select surface biased
>> jet.
>> For that you need to show the same dijet Aj measurement in isobar
>> like
>> in Au+Au. If you have any result to demonstrate that you are
>> selecting
>> surfaced bias jet in Isobar, please show those results.
>> I think we have not done that study.
>>
>>>
>>> Slide:10
>>> _ 1st bullet: Why it is important for Dijet imbalance discussion
>> here?
>>> You are doing inclusive jet v_n measurement. Not clear to me.
>>>
>>> See above.
>>
>> Please see above my concerns.
>>
>>>
>>> SLide12
>>> _"A jet in plane interacts with less medium than one out of plane"
>> ->
>>> "A
>>> jet interacts less with medium in plan than out of plane"
>>> Changed.
>>> __"Since jet production is isotropic, differences in yields are a
>>> result_
>>> _of medium interactions" Not sure, _what you_ want to say here?
>>> Please_
>>> reprhase_._
>>> Changed.
>>> __" like flow" Remove this._
>>> I included this to help give context for the measurement to an
>>> audience who may be familiar with flow studies, but not jet
>> anisotropy
>>> studies.  If you feel this is misleading I will remove it.
>>> __ you do not discuss what is v_{2}^{jet} is?_
>>> Changed equation to remove \Delta\phi -> \Psi_2 - \Phi_jet
>>> __"Not a flow effect though!" Can you elaborate this?_
>>>
>>> I am stating that although it may be described using the same
>>> framework as flow measurements, jet v2 is a different process.
>>
>> I would suggest to give a clear idea what could be that different
>> process, For example...?
>> Otherwise do not create unnecessary doubt or make statement just for
>> a
>> buzz?
>>
>>>
>>> SLide13
>>> _RHIC produces a different, cooler QGP -> "RHIC produces a cooler
>> QGP
>>> medium than the LHC"
>>> Changed.
>>> __"Down to 10 _GeV"_ -> But you are not going to show down to 10
>> GeV.
>>> So_
>>> _just remove this extra quantifier _subbullet. Main bullet is
>> fine.
>>>
>>> I do show down to 10 Gev though, my first point is 10-12.5 GeV/c
>> jets.
>>>
>>> Slide15:
>>> - Jet trigger -> You don't use any jet trigger and BEMC info in
>> your
>>> measurement. If yes, just remove.
>>> I do use the barrel high tower trigger in my analysis, as detailed
>> in
>>> the preliminary figure request.  I have clarified this as high
>> tower
>>> trigger rather than jet trigger.
>>> _- Right side STAR detector, please indicate where is TPC, BEMC,
>> EPD_
>>> _- Mention kinematic acceptance of these detectors_
>>>
>>> See updated slides, Yi mentioned this as well
>>>
>>> Slide16:
>>> _you did not discuss what is Delta_phi?
>>> I did not, but I am not sure I need to on this slide.  I will
>> discuss
>>> it on the next slide.
>>> __right side plot, _make title_/_lable_ of x-, y-axis bigger so
>> that
>>> it will_
>>> _be visible. And also legends _in side_ the plot._
>>> Changed, made entire plot larger as well
>>>
>>> Slide18
>>> Move this slide after Slide15
>>>
>>> Changed.
>>>
>>> Slide19
>>> _INside fig, mention "red line" is fit fun.
>>> Added.
>>> __ inside fig, p_T^reco -> p_{\rm T, jet}^{reco} ; 12.5 -> 12.5
>> GeV/c_
>>> Changed.
>>> __ you did not mention anywhere before what is "R"? And what jet
>> _R
>>> you
>>> are_ going to _do measurement_?_
>>> It is labeled on the plot, and I will discuss it further on the
>>> following slide.
>>> __ what is v_{2}^ch? Need to mention _it charged_ jet v2. I would
>>> suggest_
>>> to use $v_{2}^{\rm ch, jet}$; And the same about v_{2}^ch,abs
>>>
>>> Changed.
>>>
>>> Slide20:
>>> Before slide20, you need to discuss different jet v2 (all, hard
>> core,
>>> matched jet) and their spectra showing side-by-side
>>>
>>> I'm not sure I understand why?  I think that was a good check to
>> make
>>> and certainly worth having in the backup, but the measurement
>> being
>>> presented is jet v2 using the hard core matching criteria, the
>> need
>>> for which is motivated earlier in the talk.
>>>
>>> Slie21:
>>> _  "Jet v2 is a exciting measurement for determining the
>> path-length
>>> dependence of jet quenching" -> This statement is fine to
>> motivate.
>>> But
>>> for your conclusion this may not be relevant. Because we don't
>> have
>>> jet
>>> v2 measurement for different path length/system size with the same
>>> kinematic coverage. And you did not discuss what is the strategy
>> for
>>> your measurement unless you plan to do the same in AU+AU.
>>>
>>> _"Jets which are in plane interact with a different amount of the
>> QGP
>>> than those out of plane" Not sure how do you get this conclusion
>> from
>>> your measurement.
>>>
>>> I have updated my conclusions to better reflect the points I wish
>> to
>>> make and where I will go next with this analysis.
>>>
>>
>> Thank you
>> Nihar
>>> On Thu, Oct 6, 2022 at 1:34 PM Yi Yang <yiyang0429 AT gmail.com>
>> wrote:
>>>
>>>> Dear Tristan,
>>>>
>>>> Thanks a lot for the reply and the updated version.
>>>> They look very good to me.
>>>> Let's wait for your study and the decision on the preliminary
>>>> results!
>>>>
>>>> Cheers,
>>>> Yi
>>>>
>>>> On Thu, Oct 6, 2022 at 3:26 AM Tristan Protzman
>> <tlp220 AT lehigh.edu>
>>>> wrote:
>>>>
>>>> Hi Yi,
>>>>
>>>> Thank you for the feedback!  I have uploaded an updated version
>> and
>>>> addressed your comments below.
>>>>
>>>> - p4: Are the sub-bullet for the 3rd bullet and the 4th bullet
>> the
>>>> same?
>>>>
>>>> Yes, I have removed that redundancy.
>>>>
>>>> - p6: toy mode --> toy model
>>>>
>>>> Fixed.
>>>>
>>>> - p9: Just for my own education, could you please tell me why A_j
>>>> can be less than 0 (I am assuming pT^1 and pT^2 are leading and
>>>> subleading jet pT, respectively, is it correct)?
>>>>
>>>> Yes, (pT^1, pT^2) is the (leading, subleading) jet pT.  The red
>>>> points are the measurement of A_j using only hard cores.  This is
>>>> where leading and subleading are determined, thus no points below
>> 0.
>>>> However, after matching is done, leading and subleading are not
>>>> recalculate, so it is possible for the subleading hard core to
>> match
>>>> to a jet with more momentum than the leading hard core does,
>>>> resulting in negative A_j.  There are a few ways this could
>> happen.
>>>> The subleading jet could contain a larger soft component than the
>>>> leading jet, thus when added to the hard core the magnitudes
>> flip.
>>>> Additionally, because of the fluctuating background the leading
>> jet
>>>> could be over subtracted and the subleading jet under subtracted,
>>>> again flipping the relative magnitude.  This would not affect the
>>>> hard core since background subtraction is not done on that
>>>> collection.
>>>>
>>>> - p15: It would be good if you can provide more information for
>> the
>>>> subdetectors, for example eta and phi coverage...
>>>>
>>>> I added more information about each system and labeled the
>> picture.
>>>>
>>>> - p18: Jet v2 not feasible --> Jet v2 is not feasible
>>>>
>>>> Changed to Jet v2 was not feasible
>>>>
>>>> Cheers,
>>>> Tristan
>>>>
>>>> On Wed, Oct 5, 2022 at 1:59 PM Yi Yang <yiyang0429 AT gmail.com>
>> wrote:
>>>>
>>>> Hi Tristan,
>>>>
>>>> Thanks a lot for the nice slide. I have some suggestions/comments
>>>> for your consideration.
>>>> - p4: Are the sub-bullet for the 3rd bullet and the 4th bullet
>> the
>>>> same?
>>>> - p6: toy mode --> toy model
>>>> - p8: Title: Hardcore --> Hard core
>>>> - p9: Just for my own education, could you please tell me why A_j
>>>> can be less than 0 (I am assuming pT^1 and pT^2 are leading and
>>>> subleading jet pT, respectively, is it correct)?
>>>> - p15: It would be good if you can provide more information for
>> the
>>>> subdetectors, for example eta and phi coverage...
>>>> - p18: Jet v2 not feasible --> Jet v2 is not feasible
>>>> - Since we are not settled with your preliminary results yet, I
>>>> will comment on p20 and p21 later. :-)
>>>>
>>>> Cheers,
>>>> Yi
>>>>
>>>> On Thu, Oct 6, 2022 at 12:36 AM Tristan Protzman via Star-hp-l
>>>> <star-hp-l AT lists.bnl.gov> wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I submitted this material for review last week, but it seems to
>> have
>>>> been lost somehow, so I am resending it.
>>>>
>>>> Cheers,
>>>> Tristan
>>>>
>>>> On Wed, Oct 5, 2022 at 12:33 PM webmaster--- via Star-hp-l
>>>> <star-hp-l AT lists.bnl.gov> wrote:
>>>> Dear Star-hp-l AT lists.bnl.gov members,
>>>>
>>>> Tristan Protzman (tlp220 AT lehigh.edu) has submitted a material for
>> a
>>>> review,
>>>> please have a look:
>>>> https://drupal.star.bnl.gov/STAR/node/61264
>>>>
>>>> Deadline: 2022-10-11
>>>> ---
>>>> If you have any problems with the review process, please contact
>>>> webmaster AT www.star.bnl.gov
>>>> _______________________________________________
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>>>> https://lists.bnl.gov/mailman/listinfo/star-hp-l
>>> _______________________________________________
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>> _______________________________________________
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>
> --
>
> Rosi Reed
> RHIC/AGS UEC member
> Associate Professor, Physics Department
> Lehigh University
> (610)758-3907
> 16 Memorial Drive East Office 406
> Bethlehem, PA 18015
> she/her/hers
>
> Links:
> ------
> [1]
> https://urldefense.com/v3/__https://physics.fjfi.cvut.cz/files/predmety/02RQGP/zs1617/GyulassyPluemer.pdf__;!!P4SdNyxKAPE!Ez8frSqNJbBBgywunqqEJilI-3bnKgpyx5zAD_HBfZVBjsvOPutfr1MohqqCsvBHTEzGzKHaD71BzzjqNgYSMSxtUg0$

--

Rosi Reed
RHIC/AGS UEC member
Associate Professor, Physics Department
Lehigh University
(610)758-3907
16 Memorial Drive East Office 406
Bethlehem, PA 18015
she/her/hers