STAR HardProbes PWG

[Yi Yang <yiyang AT ncku.edu.tw>]

Dea Leszek,

(I added this to the HP list, probably we can discuss it there.) 

Sorry again for the late response. 

I have some comments/questions on your analysis note and I will send out my comments on your paper draft in a separate email. 

 

- Abstract: remove all "J/psi" related things. 

- p12: Any references for the "flag" information or definition? 

- p12: Should include the eta range in the second paragraph.   

- p13: Move Figure 24 to Figure 23 (since the current Fig. 23 was mentioned later). 

- p14: You mentioned several variables: R_SMD, E_TOW/E_CLU, E_CLU/p, ... how did you choose these cut values? Can you show some studies or references? 

- p17: The fitting of the Upsilon signals. Since STAR doesn't have a good resolution to separate Upsilon states, it is very tricky to fit the signal. You can take a look at how ATLAS did (they have similar mass separation power), just for your reference.  https://arxiv.org/pdf/1211.7255.pdf  (Section IV C.)

- p19: It is still strange to me that you do a bin counting from a range and then move the contaminations from other states from the fit. Why do you just integrate from the fit? (I understand you use this as the systematic, but the procedure is a bit strange to me.) 

- p23: Figure 2.10 (b): why the uncertainties on 2S and 3S only have up-forward or down-forward uncertainty? 

- Could you please provide the full function used in your fit? 

- All mass plots (especially for the plots used in paper), I would think the style can be improved a bit: all the font sizes are too small, the bottom panels can move up and combine to the top panel (share the same x-axis). Since you are using unbinned-likelihood fit, you can make the plots with coarser binning. Difficult to read the label on the y-axis in the bottom panels. 

 - p26: First paragraph. Section ??

 - p26: Table 2.7: invariant mass cut < 0.04 GeV/c^2 --> Should it be 0.3 GeV/c^2?  I think other heavy-flavor electron analyses used 0.2 GeV/c^2. Can you add the mass plot of your photonic electrons in the note? 

 - p29: Electron efficiency:  

          - Figure 2.16: there is an "acceptance" in the electron efficiency, can you define it? Naively, I thought the electron efficiency should only be calculated inside the TPC acceptance. 

          - Do you expect the efficiencies for electrons and positrons to be different? If not, why don't you combine them? 

 - p29: Upsilon efficiency: 

          - How do you define acceptance? Can you add it in the note? 

 - p30: The main concern I have is in the result of cross-section vs y and I remember we discussed intensively and the reason is that you have similar raw yields for 2S and 3S in |y| < 0.5 and 0.5 < |y| < 1, but the efficiencies has a factor of 2 difference (Fig. 2.17 (b) and (c). Do you know why L0 efficiencies are different in two rapidity ranges? I remember Ziyue and others found that the n_sigma_e has some dependency on eta. Could you please also check it on your dataset? 

 - p31: Did you also consider "shifting" the mean of the track resolution?   

 - p39: Systematics: Please add more details of your systematic uncertainty study. It would be good to have all the plots included. So far, you only have a short description and the final number for each source. 

 - p45: Chapter 3: Lots of links to Figures or Sections are missing, for example p47, Figure ?? and Figure ?? in the second paragraph. 

 - p50: Figure 3.5 (b): I am still worrying about the "dip" in 3S state, it seems that there is a ~3 sigma effect from "flat". We probably really need to understand it before we release this result, since it might cause lots of discussion from the theorists' side. (I am not saying it is wrong, but we will need some understanding and explanations. 

 - Similar comments on the results plots, the style probably can be improved. (But this can be done in the GPC stage.)

 - Figure 3.4 and 3.5: I still don't understand why we need to mirror the points to the negative rapidity. It won't give us any more information, you can just simply change the x-axis to |y| and plot to data points. 

 - You can make all your plots much larger. 

 - p56: NLO [?]

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 Wed, Feb 16, 2022 at 11:03 AM Leszek Kosarzewski via Star-hf-l <star-hf-l AT lists.bnl.gov> wrote:

Dear All

As I presented today, the Upsilon states in p+p 500 GeV paper is ready for review.

Paper page:

https://drupal.star.bnl.gov/STAR/blog/lkosarz/upsilon-production-pp-500-gev

Paper:

https://drupal.star.bnl.gov/STAR/system/files/Upsilon500_Paper_LK_v6.pdf

Technical notes:

https://drupal.star.bnl.gov/STAR/system/files/Upsilon500_TechNotes_LK.pdf

I also updated the presentation to answer today's questions (see slides 24-29):

https://drupal.star.bnl.gov/STAR/system/files/Upsilon_HF_LK_2022_2_15.pdf

The tracking efficiency uncertainty is actually correct. It affects the shape of N_ch distribution and also the shape of Upsilon N_ch distribution through unfolding correction. For Upsilons also the input distribution is affected by the efficiency from embedding and signal extraction. In the simulation for unfolding correction the uncertainty is estimated by changing the efficiency by +/-5%. For the Upsilon signal, the nFitPts is changed by +/-2 in embedding and data. The cumulative effect of all of that is large for the last Nch bin. Also if the shapes are changed this means that the effect on Nch/<Nch> will not cancel out enirely, though the effect is lower than the input +/-5%. In addition the bins are fixed with default <Nch>. The J/psi paper shows similar values for these uncertainties.

The 4Cx uncertainty also affects the data in this way. Upsilons are affected by the change in both Upsilon and min-bias Nch distributions, so again the effect is larger on Upsilons.

I also checked the eta and y distributions and efficiencies. There is a dip for triggering track, but this is not shown in y distribution of Upsilon candidates.

Best regards, Leszek

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