STAR HardProbes PWG

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

Hello Barbara,

Thank you for addressing my comment and answering my questions.
I don't have any further comment. I sign off.

Cheers
Nihar


On 2022-08-19 14:06, Barbara Trzeciak wrote:
> Hi Nihar,
>
> thanks for the comments. I've uploaded a new version:
> https://drupal.star.bnl.gov/STAR/system/files/STARHFOverview_BTrzeciak_v2.pdf
>
> Please see my replies inline below.
>
> > Slide-2:
> > _Initial hard scattering, m_Q >> L_QCD -> I think this should be
> > "Initial hard scattering,  Q >> Λ_QCD" (here Q is momentum
> > transfer; Δt
> > << 1 fm)
>
> Here the argument is about heavy quarks' masses - since the mass is
> larger than the typical non-perturbative QCD scale, the quark quark
> production cross section is calculable with pQCD.
> I modified this bullet a bit.
>
> > _"negligible thermal production, mQ >> T_QGP" -> is not that heavy
> > quark
> > mass m_Q >> T_QGP? I think there is no thermal production of
> > heavy-quark. Am I correct?
>
> There can still be some thermal production, from processes like
> gg->ccbar in the QGP.
> This should depend on the initial temperature and for RHIC, where
> temp. is of the order of 350-400 MeV, it's expected to be negligibly
> small - PHYSICAL REVIEW C 77, 024901 (2008).
>
> > Slide-6
> > Can you please point out if there is any relation between D^0 RAA
> > and
> > D^(+/-)/D^{0} yield ratio?
> > Is there any physics link between Strong suppression of D^0 RAA and
> > D^(+/-)/D^{0} Au+Au same with Pythia8?
> > (Just for my understanding as you put these two figures on one
> > slide)
>
> Here indeed it might not be so obvious. I've put back the plot with
> both D0 and D+ Raa.
> It should be more clear now.
>
> > SLide-8
> > What are these "*" and " ** " in the uncertainty?  [Please mention
> > it]
>
> Explained, thanks for catching it.
>
> > Slide-13:
> > "…unity → suppression…".  I would remove "arrow" and replace
> > "and";
> > (It reads like RpA unity  indicate RAA Strong suppression in AA; I
> > this
> > these are two separate physics: cold vs hot QCD)
>
> Here the point is that the suppression in AA can be not only due to
> the hot nuclear matter effects, but also cold nuclear matter effects
> can play a role.
> In order to quantify the CNM we measured R_pAu, since at high pT it's
> consistent with 1 we can conclude that the suppression seen in AA is
> due to the QGP related effects.
> So I wouldn't say there are two separate physics, CNM effects are
> present in AA collisions as well.
>
> > > Slide-16:
> > > "small regeneration or/and small charm quark flow."
> > > For my understanding,   "small regeneration creates zero v2" Or "
> > > Zero
> > > v2 hence small regeneration" ?
> > > I think latter is true. Right?
>
> Yes, zero v2 points to a sall regeneration effect (in case charm
> quarks flow) or charm quarks' flow is small.
>
> > Outlook:
> > I would suggest to include BUR HF kinematic coverage plot for
> > different
> > observables.
> https://drupal.star.bnl.gov/STAR/system/files/OnlyHPProjectionBUR.pdf
>
> The kinematic coverage is nice, but I think that it doesn't show the
> physics performance as good as the statistical project plots.
> So I would prefer to  leave the plots that I have now and since I have
> only 15+5min (not 20+5 as initially suggested by the organizers) I
> have to skip many things in the presentation.
> I will keep it in the backup.
>
> Cheers,
> Barbara
>
> On Fri, Aug 19, 2022 at 8:12 AM Nihar Sahoo via Star-hp-l
> <star-hp-l AT lists.bnl.gov> wrote:
>
> > A small correction on Slide16 comment:
> >
> > Slide-16:
> > "small regeneration or/and small charm quark flow."
> > For my understanding,   "small regeneration creates zero v2" Or "
> > Zero
> > v2 hence small regeneration" ?
> > I think latter is true. Right?
> >
> > Regards
> > Nihar
> >
> > On 2022-08-19 11:40, Nihar Sahoo wrote:
> > > Hello Barbara,
> > >
> > > Please find my comments and questions below on your nice
> > presentation.
> > > Slide-2:
> > > _Initial hard scattering, m_Q >> L_QCD -> I think this should be
> > > "Initial hard scattering,  Q >> Λ_QCD" (here Q is momentum
> > transfer;
> > > Δt << 1 fm)
> > > _"negligible thermal production, mQ >> T_QGP" -> is not that heavy
> > > quark mass m_Q >> T_QGP? I think there is no thermal production of
> > > heavy-quark. Am I correct?
> > >
> > > Slide-6
> > > Can you please point out if there is any relation between D^0 RAA
> > and
> > > D^(+/-)/D^{0} yield ratio?
> > > Is there any physics link between Strong suppression of D^0 RAA
> > and
> > > D^(+/-)/D^{0} Au+Au same with Pythia8?
> > > (Just for my understanding as you put these two figures on one
> > slide)
> > > SLide-8
> > > What are these "*" and " ** " in the uncertainty?  [Please mention
> > it]
> > > Slide-13:
> > > "…unity → suppression…".  I would remove "arrow" and replace
> > "and";
> > > (It reads like RpA unity  indicate RAA Strong suppression in AA; I
> > > this these are two separate physics: cold vs hot QCD)
> > >
> > > Slide-16:
> > > "small regeneration or/and small charm quark flow."
> > > For my understanding,   "small regeneration" due to zero v2 Or "
> > Zero
> > > v2 hence small regeneration" ?
> > > I think latter is true. Right?
> > >
> > > Outlook:
> > > I would suggest to include BUR HF kinematic coverage plot for
> > > different observables.
> https://drupal.star.bnl.gov/STAR/system/files/OnlyHPProjectionBUR.pdf
> > > Regards
> > > Nihar
> > >
> > > On 2022-08-18 15:29, webmaster--- via Star-hp-l wrote:
> > > > Dear Star-hp-l AT lists.bnl.gov members,
> > > >
> > > > Barbara Trzeciak (barbara.trzeciak AT gmail.com) has submitted a
> > material
> > > > for a
> > > > review, please have a look:
> > > > https://drupal.star.bnl.gov/STAR/node/60559
> > > >
> > > > Deadline: 2022-08-30
> > > > ---
> > > > If you have any problems with the review process, please contact
> > > > webmaster AT www.star.bnl.gov
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