STAR HardProbes PWG

["Ma, Rongrong" <marr AT bnl.gov>]

Hello Tristan

In the interest of time, here are my comments for you to consider. 

s2
- I am not sure about the second bullet, which seems to indicate that it is 
useless/impossible to study QGP in the soft section. Actually, we have learnt 
a lot about QGP from studying its bulk properties. I suggest to remove this 
bullet or rephrase it. 

s3
- Hard parton scatterings -> Hard partonic scatterings
- cross-section -> cross section
- a direction connection -> a direct connection
- There is good agreement between theory and experiment for jet cross section 
over a wide range of kinematics
- remove "STAR arXiv:2111.08149" since this is a STAR preliminary result and 
you are presenting on behalf of STAR

s4
- Last bullet: I think you need to be a bit more specific here. Do you intend 
to say collisional and radiative processes have different path-length 
dependences? If so, please say it explicitly. 

s5
- Two leading jets, found by the k_T algorithm, are excluded
- Jet background -> Background
- Combinatorial jets are clustered from the soft background -> Combinatorial 
jets are made of particles solely from soft background
- To a jet finder, real and combinatorial jets look the same -> A jet finder 
could not distinguish between real and combinatorial jets
- How can we distinguish -> How can we identify

s6
- Combinatorial jets should fragment in a soft manner, so we attempt to 
select jets with hard fragmentation patters -> Combinatorial jets are made of 
soft particles, so we attempt to select jets with hard fragments
- GeV -> GeV/c (fix this throughout the presentation)

s7
- The cartoon illustrates a hard-core di-jet. Is this what you are using? If 
so, I think you need to say it explicitly on s6. Currently, one could not 
deduce this from s6. 
- remove "down within the jet resolution"
- which look like jets -> as hard processes
- selection -> production

s8
- looked at -> studied
- 2-jet events, jet back-to-back with transverse momentum -> 2-jet events 
with back-to-back jets
- in momentum -> in transverse momentum
- shows the jet is modified -> shows that jets are modified
- in the matched jets -> in the matched jets of R = 0.2

s9
- by using the initial event geometry in our description -> by utilizing the 
initial collision geometry
- is the participant plane -> lies within the participant plane 

s10
- A heavy ion collision can be parameterized by its -> A heavy-ion collision 
can be characterized by its
- Impact Parameter -> Impact parameter
- Reaction Plane -> Reaction plane

s11
- differences in yields are a result of medium interactions -> differences in 
yields w.r.t. the event plane are expected as a result of path-length 
dependent energy loss
- remove ", in the same fashion as low pT particles (flow)"

s12
- at LHC energies -> at the LHC

s13
- remove "medium"
- 5.2 billion minimum bias collisions recorded -> About 4 billion minimum 
bias events

s14
- Records -> Reconstructs
- remove "Used for jet finding"
- remove "for jet finding"
- Add BEMC acceptance
- Forward event plane finding -> Event plane reconstruction

 s16
- was difficult -> measurement was difficult
- Jets bias a mid-centrality determination of the event plane -> Jets bias 
the determination of the event plane at mid-rapidity

s17
- Increase the size of the text in the figure. It is too small to see. 
- Anti -> anti

s18
- The result -> The yield
- Left figure: the legend is too small to see
- Within the figure, change "p_T,jet^reco" to "p_T,jet^reco,ch". See the 
x-axis title of the figure on s17

s19
- Figure
-- x-axis and y-axis titles are too small to see
-- Change x-axis title to be "p_T,jet^reco,ch, p_T,jet^ch (GeV/c)" since the 
ALICE results are unfolded
-- 20%-60% Central -> 20-60% Mid-central
-- 30%-50% -> 30-50%
-- No Jet p_T Correction Applied -> No Correction on Jet p_T Applied

s20 
- non-zero v2 in jet triggered -> non-zero jet v2 in
- then small R_pPb -> then R_pPb < 1
- is not complete. Studies in medium size systems will be useful

s21
- high p_T charged particle RAA -> high p_T charged particle suppression
- Small systems v_2^jet -> v_2^jet in small systems
- for high p_T isobar R_AA -> for high p_T R_AA in isobar collisions
- Exploration -> exploration
 
Best
Rongrong



> On Oct 10, 2022, at 2:42 PM, Tristan Protzman via Star-hp-l 
> <star-hp-l AT lists.bnl.gov> wrote:
> 
> Hi All, 
> 
> Thank you for the many helpful comments.  My responses are below, I have 
> updated the draft on Drupal.
> 
> Sooraj's Comments: 
> Thanks Sooraj - I have removed the note about the different kinematics on 
> slide 19 and instead mention that the ALICE results are unfolded.  
> 
> Barbara's Comments: 
> - s3: increase a bit the size of the plot
> - s5:  a fluctuating, background ->  a fluctuating background
> - s8: add "STAR" before the journal name in the figure's reference
> - s12: similarly, add there names of the collaborations to the references
> - s13: you can indicate here the size of the isobar samples
> - s14: add that the 3.4 trigger is on E_T
> - s16: increase size of the resolution figure
> All above have been changed
> - s19: would be good to quantify the non-zero v2 in terms of sigma
> Added - the average is 3.5 sigma away from zero
> - s19: since the systematic uncertainty for now is only from the bkg. 
> subtraction, I would specify it on the plots in your "Systematic 
> Uncertainty" label. 
> I would also add some information on the sys. unc. on the slide.
> Thanks - I added some text clarifying these points
> 
> Helen's Comments:
> Thanks Helen, I think these are great points suggesting that there is 
> something here, while making it clear that we are not ready to offer a full 
> explanation of the results.  I have updated my conclusions to reflect this.
> 
> Yi's Comments:
>   - General: how long is your talk? Just want to make sure you can finish 
> it in time. 
> It is a 15 minutes talk, when I rehearsed with the Lehigh group today I 
> came in just over 15 minutes, so with a little bit of tightening up 
> transitions I should be right on time. 
>   - p18: the label on x-axis: Delta phi (should be together), and a space 
> before "=".  
> Thanks, fixed!
>   - p19: I would use "Observed a non-zero v_2^ch jet at low pT in a medium 
> sized system" (same for the conclusion). 
>             (I probably missed some discussions, did you check the 
> significance for the first two bins?) 
> Averaged over all bins it is 3.5 sigma from zero, addressed with Helen and 
> others' comments
>   - p21: diiferent --> different 
> Fixed!
> 
> Notes from Lehigh Rehearsal
> Slide 7: Added geometric matching requirements (dR = 
> \sqrt{(\eta_{hc}-\eta_{jet})^2 + (\phi_{hc}-\phi_{jet})^2} < R_{resolution})
> 
> Switched order of slides 15 and 16 - Explain event plane calculation first, 
> then need for forward detector
> 
> Cheers,
> 
> Tristan 
> 
> On Mon, Oct 10, 2022 at 12:38 PM Yi Yang <yiyang AT ncku.edu.tw> wrote:
> Hi Tristan,
> 
> Thanks a lot for the updated slides and they look good to me. 
> I only have a few comments/suggestions on v6 for your consideration. 
>   - General: how long is your talk? Just want to make sure you can finish 
> it in time. 
>   - p18: the label on x-axis: Delta phi (should be together), and a space 
> before "=".  
>   - p19: I would use "Observed a non-zero v_2^ch jet at low pT in a medium 
> sized system" (same for the conclusion). 
>             (I probably missed some discussions, did you check the 
> significance for the first two bins?) 
>   - p21: diiferent --> different 
> 
> Cheers,
> Yi
> 
> 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> Yi Yang, Associate Professor 
> Department of Physics 
> National Cheng Kung University 
> Tainan, 701 Taiwan 
> E-Mail: yiyang AT ncku.edu.tw 
> Tel: +886-6-2757575 ext.65237 
> Fax: +886-6-2747995
> Group Web: http://phys.ncku.edu.tw/~yiyang 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> 
> On Mon, Oct 10, 2022 at 1:24 AM Tristan Protzman via Star-hp-l 
> <star-hp-l AT lists.bnl.gov> wrote:
> Hello Nihar, 
> 
> An updated draft has been uploaded.  I believe I have kept up on the 
> conversation between you and Rosi while I was working on these changes, 
> please let me know if I missed something. 
> 
> 1) Have you updated your remaining sys uncertainty that we were waiting
> for?
> No, my jobs are still processing, they seem to be moving through rather 
> slowly compared to what I am used to.  I took a quick look at what has been 
> produced so far and it seems consistent with the existing measurement.  
> 
> 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
> I have added a label for STARs systematics, but did not remove the ALICE 
> legend
> 
> Slide17 fig:
> _ Can you include v2 value (with uncertainty) in this figure that you
> get from the fitting?
> It was a deliberate choice not to since the v2 of the fit is the observed 
> v2, not corrected for the event plane resolution.  I felt it would be 
> confusing to quote one value there and then on the next slide show a 
> different value for the bin.  
> 
> 
> 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.
> I had moved the slide on EPD resolution to the backup for time, what I 
> think I could do is move the diagram of the EPD on slide 16 to slide 15, 
> and instead have a resolution plot in its place. 
> 
> I will remake the resolution plot to better fit the space available, but 
> this will take a little time soI leave it as is for now.
> 
> 
> 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?
> Throughout this talk I have been motivating the idea that if we have a 
> non-zero jet v2, then the jets in plane and out of plane (which experience 
> a different length through the medium)  are modified different amounts.  
> Hence, path length dependent jet modification.  
> 
> 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
> Changed the last bullet to "Evidence of non-zero v2 in a medium sized 
> system"
> 
> 5) Slide19(v4 version)
> _"A very different system!" -> "A very different kinematic range and
> system size"
> Changed. 
> _"v2ch jet is observed despite the introduced surface bias" -> "v2ch jet
> is observed despite the possible surface bias"
> Changed
>     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.
> I have changed the wording as suggested to be less strong, however I feel 
> it is still important to bring up.  Either there is a surface bias 
> introduced, in which case it is a little surprising we observed jet v2 at 
> all, or there isn't a surface bias like we see in Au+Au, in which case our 
> understanding of jet measurements is incomplete.  
> 
> _"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
> Elaborated to explain that it seems jet v2 may not be only a path length 
> effect, as it is in our usual picture of jet quenching.  .
> 
> 
> > 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.
> The point of mentioning the strong coupling at low Q2 is to explain why we 
> cannot simply use perturbative calculations to study the QGP, and instead 
> need a different probe like jets.  If there is nothing factually wrong, I 
> would prefer to keep this.  
> 
> 
> 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"
> Changed
> _"Both collisional and radiative" -> "Both collisional and radiative
> energy loss" or "Parton energy loss via both collisional and radiative
> processes"
> Changed
> 
> 
> 
> Slide 5
> > __"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.
> Added uncorrelated.  
> 
> Slide5 (current v4), right figure is from STAR data or any model? No
> description mentioned there.
> Added description
> 
> 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.
> I believe Rosi's comments address my thoughts on this as well
> 
> Slide 12
> > 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?
> Rephrased
> 
> Cheers,
> 
> Tristan 
> 
> On Sun, Oct 9, 2022 at 12:03 PM Nihar Sahoo via Star-hp-l 
> <star-hp-l AT lists.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
> >>>> _______________________________________________
> >>>> 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
> >>> _______________________________________________
> >>> 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
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> >> https://lists.bnl.gov/mailman/listinfo/star-hp-l
> > 
> > --
> > 
> > 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$
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