STAR HardProbes PWG

[Helen Caines <helen.caines AT yale.edu>]

Hi Nihar,

  Let me comment on your interpretation questions. Andrew will take care for the presentation/style points. He is also rehearsing his talk here at Yale today, so he will post a new version later today/tomorrow where some of the fine wording may be tweaked,

 But the data points have been consistent for a while now, its just a questions of how to present on log or pin scales.

General comment:
I don't understand the behavior of EEC vs dR with the new normalization scheme.
Because, at RHIC energy it shows q/g phase has also non-linear trend that looks like 1/R^2 trend at high dR with a peak at gray region (see Slide18 for example).

It is  non-linear in d(Delta(R)) normalization, which it has to be since it was close to flat in  d Log((Delta(R))). This is not unexpected and the different normalizations, which are just normalizations and not a change in the calculation of the correlation calculated, emphasize different points of interest in the correlation function. There is the transition point that is expected to be at Transition ~ ( k *  Lambda_QCD ) / Jet_pt  ; where k is a constant. This is what Andrew sees and wants to emphasize in his talk.

The “plateau” region is not quite flat and the ratio of the slopes of different N-point correlations (Andrew has N=2) are related to alpha_s. Andrew does not focus on this as at the jet pT relevant to RHIC the plateau range in small.

Only low jet pT 15-20 GeV does match with the story like slide#5 right plot.
Why?

I don’t know what you are asking here, can you try again?

This slide's comparison with CMS open data does not make sense to me.
On the one hand we say (in slide15) "transition region moves as 1/pTjet"
And then in this slide16 we are comparing RHIC 15-20 Gev/c jet pT with LHC 500,550 GeV jet pT, and showing values are 2.7 and 2.5 GeV/c, respectively; same order of magnitude?

Not sure what doesn’t make sense. The theorists told us that "Transition point” / pT = constant =  k * lambda_QCD . As best as we can currently read off the transition region from the RHIC data (Yi has a good point about how to make this more rigorous after HP) and the LHC MOD data their prediction is correct. That’s very nice given the more than order of magnitude difference in jet energy measured.

"Same Order of magnitude implies universality between collision energies!"
What universality we are pointing to?

The universality of the turning point, which according to theory is proportional to Lambda_QCD. The factor k they are interested in as it related to some approximations they can/can’t make but that’s a detail for further discussion with them.

Why not that universality holds for RHIC higher jet pT?

It does, I do not understand why you think it doesn’t. The transition point” / pT = constant for all Andrew’s measurements and approximately the same as the LHC data. 

This interpretation does not sound coherent.

It is fully consistent  there is really nice agreement between his data and the theory calculation performed at his jet energies by Kyle before seeing the data. This is all great. PYTHIA also shows good agreement, which is also nice to see. 

Helen

Slide:20
Please provide paper "Kyle Lee, MIT " reference here

This is a private communication. Andrew can you please label it as such, even in the plots so the credit to Kyle doesn’t get lost if people take your figures in the future

Helen

Cheers
Nihar

On 2023-03-22 14:02, Andrew Tamis via Star-hp-l wrote:

Hello Nihar,
Thank you for the nice comments, I have implemented them.
I have also received the theoretical predictions from Kyle Lee at MIT,
which was normalized differently than my analysis: He normalized both
the overall integral and x-axis scaling to Delta(R) rather than
log_10(DeltaR). In order to make this comparable, I divided each of
my bins by their equivalent length in DeltaR: changing my distribution
from d(...)/d(Log_10(DeltaR)) to d(...)/d(DeltaR) and integrated them
out to one in that space (Formula Updated on slide 5). Nothing
changed about the analysis except for a scaling at the very end, so
this is still the same data. Now that they are normalized the same
way, I have included the comparisons with Kyle's theory calculations,
normalizing his to the same area as mine within the region that they
are plotted.
I have updated my plots and uploaded them to drupal here: Preliminary
Plots for Energy-Energy Correlator Measurement in p+p Run12 | The STAR
experiment (bnl.gov) [1]
Slide 5->6: The lines are placed by eye, In this talk I have defined
the DeltaR_Turnover as the leftmost edge of the bin which breaks the
linear scaling behavior seen in the hadronization region. My previous
slides were inconsistent about this, so I have corrected them.
Because this region has some width there are other ways to calculate
this, but I show that if one is consistent in a definition, the
calculation will yield a value in the same order of magnitude for a
given jet pT. The 3.6GeV isn't a set value, just showing that they
are all of similar scale: so I have changed this to "2 to 3GeV" to
make it less of a strong statement than asserting a value. This value
is smaller because I changed the calculation from using average pT to
the lower pT bound, which the scheme that the theoretical calculations
I received followed.
Slide 9->11: I rephrased the sentence to say what they mean, leaving
the abbreviations out, let me know if this works.
Slide 10->12: I rephrased it to "do not need to correct in addition
to pT_Jet"
Slide 17->18: The geometric cutoff is due to it becoming more
difficult to fit two particles into the cone once the deltaR reaches
the jet radius, so an increased jet R allows for the measurement to
push into larger deltaR, where we see the quark/gluon region continue.
Best,
Andrew
On Mon, Mar 20, 2023 at 3:31 AM Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>
wrote:

Hello Andrew,
Please find my comments on your nice presentation below.
___________
General comment/suggestion to all HP2023 and DIS2023 presenters:
1. Please make a Drupal page for all your preliminary plots and
provide
us the link.
If you have already done that, please send us the link.
2. While preparing your analysis plots for "STAR preliminary"
request,
please follow the guidance 1-7:
https://drupal.star.bnl.gov/STAR/pwg/common/Preliminary-figures
It saves our time.
_________
SLide:-2
t_f : mention "formation time"
SLide-5:
In plot:
Legend shows all blue, red, green markers are 15-20 GeV/c jet pT. I
think that is not the case. Please correct it. (Slide6)
As this is a PYTHIA study, I would strongly suggest to use open
marker
here.
Because you have used the same marker style while plotting the data.
Otherwise it may confuse the audience.
Each dashed line:
Have you used the _expression_ "Lambda_QCD/jet Pt" to find the value
of
Delta_R in the left plot?
If not, can you calculate what is the value if you use "ave jet pT"
of
these three cases?
Slide6:
"< 𝑝𝑇 𝐽𝑒𝑡 >*∆𝑅𝑇𝑢𝑟𝑛𝑜𝑣𝑒𝑟 ~
3.6 GeV" Not clear to me what this "3.6 GeV"
implies here?
Where do you get "DeltaR_turnover"? Have you calculated as I
mentioned
above? Or just by eye?
SLide7:
"Experimental Measurment at STAR" -> "STAR detector" (all
measurements
are experimental) (same on slide8)
You could show other colorful STAR detector pic.
"Must correct for inefficiencies …" ->" Must correct for
detector
effects…"
Slide9
Mention what is "DeltaR_jet" and "DeltaR_track"?
Both left and right slide, X, Y axis labels are too small. Please
increase the size.
Put Unit on both the axises.
Slide10
Both left and right slide, X, Y axis labels are too small. Please
increase the size.
Put Unit and title on both the axises.
"..do not need to correct additionally to 𝒑𝑻𝑱𝒆𝒕 " ->
I this we don't
need correction for EEC but "pTjet range" needs to be corrected. Is
not
that?
Slide17:
"quark/gluon region continues longer before geometric cutoff" -> do
you
understand why it is so?
Cheers
Nihar
On 2023-03-17 04:34, Andrew Tamis via Star-hp-l wrote:

Hello Barbara,
Thank you very much for the nice comments. I have implemented all

of

them and uploaded my new version, here are some notes on some of

the

changes
-s6 Added a note that I calculate average Jet pT from PYTHIA

spectra

-s10 For the second part being more technical, i have now moved my
GEANT statistical uncertainty explanation to a previous slide

where I

can talk about it in more detail, and changed some of the wording
On Slide 16 I have included a comparison with the previous CMS

result,

showing that the <pT jet>*Rturnover produces something in the same
order of magnitude, showing that this result is consistent. I

believe

this is significant, with how quickly the log axis moves and the
ambiguity in declaring the start of the turnover region (If I say

the

previous bin on my plot is the start of the transition region I

get

2.7GeV), please let me know how you think I should present this

point.

Let me know if you have any other suggestions.
Best,
Andrew
On Wed, Mar 15, 2023 at 8:49 AM Barbara Trzeciak via Star-hp-l
<star-hp-l AT lists.bnl.gov> wrote:

Hi Andrew,
please find below my comments to your nice slides.
- s2: clustered -> Clustered (to be consistent with other bullet
points)
- s3: add full reference to the right plot (same s4)
- s5,6: please improve the quality of the number values in the

Jet

pT legend
- s5: "Curve normalized to integrate to" - you can make the font

of

this bullet point a bit smaller, as it's a note
- s6: the arrows are displaced to the right from the dashed lines
- s6: when you calculate the turnover point, how do you get the
average jet pT for each range ? Do you use the PYTHIA spectra ?
- s6: you have twice "Average" in the equation, <p_T^Jet> shall

be

enough.
- s6: higher Jet transverse -> higher jet transverse
- s7: I would suggest putting here a scheme of the STAR, with the
most important detectors marked.
- s7: I would remove this "triggers on and", you mention trigger

at

the end of the sentence.
- s8: Add on the plots information about simulations, system,
energy. There's a line on the right side of the left plot.
- s8: right plot - add y-axis title, increase size of data points
and use different markers.
- s8: for Jet Pt -> x for Jet p_T
- s10: y-axis - add [%], improve quality of the legend, make the
lines wider and different styles, and I would decrease the y-axis
max so that all the contributions are visible. Add the "STAR
preliminary" label. I would suggest also using the same

description

of the sys. unc. in the legend as you have on the previous slide.
- s10: I would suggest making bullet points to be consistent with
the style of other slides, and unify the font. Also, the second

part

of the text on this slide sounds too technical, could you please
improve it and make a short point(s).
- s11: make the data point markers and font larger (e.g. you can
move the "STAR Preliminary" label up to have more space of the
text). The two plots look displayed relatively to each other.

Same

for other result plots.
- s11: "Distribution moves " - this might not be clear. Maybe:
average of the distribution moves to lower angles ...
- s12: I would remove "Doing some estimations ...", remind

instead

of the equation you show earlier
- s13, 14: make the style of the plots consistent with the

previous

plots, increase the font size, etc. Also, you can merge from down
the lower ratio plots with the upper plots.
- s15: add a conclusion bullet
- s16: Mark here again to which region each colored band

corresponds

to - as on slide 12.
- s16: Increase the font size of "Increasing R increases ... "
- s17: Increase the legend font size, and you don't need

"Corrected

Data:"
- s17: Make the conclusion sentence standing out more, and remind
what is the Effect - transition region moves to smaller opening
angles with increasing jet pT
- s17: Higher Jet Radius -> higher jet radius
- Please consistently make all the slides' titles bold (or not

bold)

Cheers,
Barbara
On Tue, Mar 14, 2023 at 2:34 AM webmaster--- via Star-hp-l
<star-hp-l AT lists.bnl.gov> wrote:

Dear Star-hp-l AT lists.bnl.gov members,
Andrew Tamis (andrew.tamis AT yale.edu) has submitted a material

for

a review,
please have a look:
https://drupal.star.bnl.gov/STAR/node/62953
Deadline: 2023-03-26
---
If you have any problems with the review process, please contact
webmaster AT www.star.bnl.gov
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Links:
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[1] https://drupal.star.bnl.gov/STAR/blog/atamis/Preliminary-Plots-Energy-Energy-Correlator-Measurement-pp-Run12-1
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