STAR HardProbes PWG

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

Hello Rongrong,

Thank you for addressing my comment and answering my questions.
I have remaining comment/suggestion, with this I sign off.

Slide#8: dN/pT (R=0.2) /dN/pT (R=0.5)  ->  dN/dpT (R=0.2) / dN/dpT 
(R=0.5)

> > "Effects of wake?" -> Do we need to point to this physics only here?
> > There are other physics also.

I agree with you, however, I think if you could mention along with this 
(Effect of wake) other three effects like "Rutherford Scattering off 
quasi-particle of QGP", "Multiple scattering and medium induced gluon 
radiation in QGP", and "Large vacuum radiation"; (In my view, one-two of 
these three effects are more feasible explanation of this observation ;) 
)
That could give a clear picture of possible effects of this observation.

> > SLide#10
> > _ Please mention "Delta R" somewhere
> > _Do we need to mention here the matching criteria?
> >  Do you mean the Delta R between HardCore and Matched jets? I will
> > mention orally that they are matched geometrically
That is fine.

> >  I am not sure about this. This is what is stated in the paper "We
> > observe a clear dijet imbalance indicating jet quenching effects in Au
> > + Au collisions for all HardCore jets including the wide angle jets."
> > Essentially, we are saying that the shapes are different between p+p
> > and Au+Au for HardCore jets.

That is OK.


> >  We have done a calculation of the total charm production cross
> > section in Au+Au, which was found to be compatible to p+p. See slide 5
> > of
> > https://drupal.star.bnl.gov/STAR/files/QM2022_poster_slides_Vanek_v09.pdf.
> > So there aren't more charm quarks produced in HI collision, but rather
> > more charm quarks form Lc and Ds, at least in the kinematic region we
> > are measuring, and consequently less for D0 and D+/-.

Thank you for this explanation.

Regards
Nihar

On 2022-07-02 20:14, Rongrong Ma wrote:
> Hello Nihar
>
> Thanks for your nice comments. A new version has been uploaded to
> Drupal.
>
> Please see my replies inline:
>
> > On Jul 2, 2022, at 1:17 AM, Nihar Sahoo via Star-hp-l
> > <star-hp-l AT lists.bnl.gov> wrote:
> >
> > Hello Rongrong,
> >
> > Thanks for sharing your nice HP talk.
> > Please find my comment and question below.
> >
> > Slide#6: "high-pT leading particle "  -> "high-pT constituent
> > particle"
>  I changed to "high-pT leading constituent". I think it is important
> to point out that the requirement is only for the leading particle,
> otherwise, people might think we make such requirement for all the
> constituents.
>
> > "single hadrons" -> "inclusive charged hadrons"
>  Done
>
> > Slide#7 "spectrum shape" I understand the reason to mention this
> > that jet pT spectra shapes are different for pi0 and gamma.
> > But not sure if it is ok to include this with color
> > factor and mean path length dependence.
> > "Spectrum shape" is after hadronization.
> > You may consider to include another bullet about "Jet
> > pT spectral shapes are different for pi0+jet and gamma+jet"
>  I added "Different spectrum shapes" as a sub-bullet now. I agree that
> it is not a motivation as other two points, but rather a consequence
> we need to deal with.
>
> > "Similar suppression for γ-jet and π0-jet" -> "Similar suppression
> > for γ-jet and π0-jet within uncertainty"
>  Done
>
> > You could also point out  that "for R=0.5, IAA(pt) shape is
> > different than R=0.2"
>  Done
>
> > SLide#8:
> > "Ratio of cross sections " -> in this context "Ratio of yield as a
> > function of jet pT"  (these are semi-inclusive measurement)
>  Changed to "Ratio of yields"
>
> > Slide#9:
> > Title "Inter-jet Broadening" -> "γ-jet and π0-jet acoplanarity" or
> > simply "Jet acoplanarity in heavy-ion collisions"
>  Changed to "Jet acoplanarity"
>
> > For this slides, I suggest to include p+p data and Pythia8
> > comparisons to convince people that both are consistent at 9-11 GeV
> > ET.
> > (For note: In case someone ask to have same kinematic comparison for
> > pp like 11-15 GeV, you could say that we have done that measurement
> > recently; but not shown here And for pi0+jet they are also
> > consistent within uncertainty; we are working for publication.)
>  This is a good point. Replaced the left plot with pp figure.
>
> I moved R = 0.2 results to backup
>
> > "Effects of wake?" -> Do we need to point to this physics only here?
> > There are other physics also.
>  This is one mechanism which seems to be able to explain both R = 0.2
> and R = 0.5. I think it would be interesting to discuss a bit about
> this. I put a question mark there to indicate it is not the only
> explanation.
>
> > SLide#10
> > _ Please mention "Delta R" somewhere
> > _Do we need to mention here the matching criteria?
>  Do you mean the Delta R between HardCore and Matched jets? I will
> mention orally that they are matched geometrically
>
> > Slide#11
> > "< AJ > " -> Do you mean average AJ ?
>  Yes
>
> > Another important info from this measurement was "No significant
> > difference between p+p and Au+Au of jet substructure with hardcore
> > selection"
> > Do you want to point this out?
>  I am not sure about this. This is what is stated in the paper "We
> observe a clear dijet imbalance indicating jet quenching effects in Au
> + Au collisions for all HardCore jets including the wide angle jets."
> Essentially, we are saying that the shapes are different between p+p
> and Au+Au for HardCore jets.
>
> > Slide#17
> > "Redistribution of charm quarks in HI collisions?" Not sure but is
> > not that "More production charm quarks in HI collisions?"
> > Trying to understand "Redistribution of charm…"
>  We have done a calculation of the total charm production cross
> section in Au+Au, which was found to be compatible to p+p. See slide 5
> of
> https://drupal.star.bnl.gov/STAR/files/QM2022_poster_slides_Vanek_v09.pdf.
> So there aren't more charm quarks produced in HI collision, but rather
> more charm quarks form Lc and Ds, at least in the kinematic region we
> are measuring, and consequently less for D0 and D+/-.
>
> > Slide#25
> > "Inter-jet broadening" -> "Jet acoplanarity"
>  Done
>
> > Slide#27:
> > Just curious: Do you know why we do not have projection of J/psi v1
> > between pT:9-14 GeV/c  where we have projection for v2 upto pT:14
> > GeV/c?
> > Is this just we don't show or any reason?
>  My guess is that the v1 measurement is much more challenging compared
> to v2.
>
> > Just a suggestion to include STAR HP kinematic coverage BUR plot for
> > RUn23+25, good to show at the end.
>  Done.
>
> Best
> Rongrong
>
> > Regards
> > Nihar
> >
> > On 2022-07-02 01:56, Rongrong Ma via Star-hp-l wrote:
> > Hello All
> > This is an invited talk on sPHENIX relevant STAR results and plans
> > at
> > the Predictions for sPHENIX RBRC Workshop
> > (https://www.bnl.gov/sphenix2022/index.php). I focus mainly on jets
> > and HF results. Please send me your comments. Thanks.
> > Best
> > Rongrong
> > On Jul 1, 2022, at 4:22 PM, webmaster--- via Star-hp-l
> > <star-hp-l AT lists.bnl.gov> wrote:
> > Dear Star-hp-l AT lists.bnl.gov members,
> > Rongrong Ma (marr AT bnl.gov) has submitted a material for a review,
> > please have
> > a look:
> > https://drupal.star.bnl.gov/STAR/node/60153
> > ---
> > If you have any problems with the review process, please contact
> > webmaster AT www.star.bnl.gov
> > _______________________________________________
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