STAR HardProbes PWG

[Yi Yang <yiyang0429 AT gmail.com>]

Dear Dandan,

Thanks a lot for the preliminary request. 

I have some minor comments/suggestions for your consideration. 

 - You should mention the "dielectron" channel somewhere. 

 - p2: Please add your advisor in the contact list. 

 - p9: I was thinking about what you explain about the difference in statistical errors between HX and CS. I still think that the statistical uncertainty should be the same in different frames. The argument you have is that the phase spaces are different, in CS you are limited to smaller phase spaces (Figure 2), so you have large uncertainty from the fit (to determine the polarization parameter). But (to me) it should be taken into account to the systematics uncertainty, in particular the polarization parameter extraction. This is the problem of the definition, not the statistics. As Zebo mentioned, if you have infinite statistics but you only have one phase space point (extreme case), you still can not determine the polarization. And it is due to the definition, not statistics (increasing statistics won't help). You can use a large statistics sample to study the effect, for example you can say in the CS frame, we will only be able to distinguish certain parameters in certain precision. 

We can leave it now for the preliminary, and we can discuss it in the publication phase. 

 - As we discussed in the meeting, the result in p9, the lambda_theta in CS frame looks very consistent with 0, but in p10, when you integrated all certaility, you see ~2 sigma effect. We might need to think of an explanation about it. 

 - Regarding the conclusions, I would say all of these are consistent with 0, and remove "the maximum deviation and small longitudinal polarization in 2 - 3 GeV" and "Hints of pT/centrality dependences". 

Cheers,

Yi

On Fri, Aug 25, 2023 at 11:12 PM Dandan via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

Hi Barbara, Yi, Nihar, Isaac and all

At yesterday's meeting, it was suggested that we discuss J/ψ polarization conclusions offline. Here I am.

I checked the values and significance of polarization parameters in different pt bin and centrality bin.

λθ significance of deviations from 0 is more than 2σ in the 0.2 < pt < 10. GeV/c in the both frames and in the 0.2 <pt <3. GeV/c in the HX.(The case of integral pt instead of pol0 fit.)

Considering the CS error is much larger, we only focus on pt dependence and centrality dependence in HX.

Regarding the use of pol1 fitting: I should admit that this is just one of our hypothesis and has no relevant physical basis. Since there are no theoretical models yet, we only want to study from the data whether these points are dependent and slope. Note that the conclusion that  wants to apply dependence, and from the fitting result of pol1, its significance is greater than 2σ.

Please let me know your comments.

Please find the slides for request preliminary slides in the link below:  https://drupal.star.bnl.gov/STAR/system/files/jpsiPolarization_RequiePreliminary_1.pdf

Thank you very much！

Best,

Dandan

发件人：Dandan <shendandan AT mail.sdu.edu.cn>
发送日期：2023-08-18 11:06:17
收件人：STAR HardProbes PWG <star-hp-l AT lists.bnl.gov>
抄送人：star-hp-l AT lists.bnl.gov,YiYang <yiyang AT ncku.edu.tw>,Isaac <isaac.mooney AT yale.edu>,Nihar <nihar AT rcf.rhic.bnl.gov>,Qian <yangqian2020 AT sdu.edu.cn>
主题：Request Preliminary: J/ψ polarization in Isobar data

Dear Convenors,

I'm sorry the slides link uploaded for the first time is broken.

Please find the slides for request preliminary in the new link below:

https://drupal.star.bnl.gov/STAR/system/files/Dandan_RequiePreliminary_3.pdf

 Thank you for considering our Preliminary request.

Best,

Dandan

发件人：Dandan via Star-hp-l <star-hp-l AT lists.bnl.gov>
发送日期：2023-08-17 23:48:24
收件人：star-hp-l AT lists.bnl.gov
抄送人：Dandan <shendandan AT mail.sdu.edu.cn>,Qian <yangqian2020 AT sdu.edu.cn>
主题：[Star-hp-l] Request Preliminary: J/ψ polarization in Isobar data

Dear Convenors,

 Please find the slides for request preliminary in the link below:

https://drupal.star.bnl.gov/STAR/system/files/Dandan_RequiePreliminary_1.pdf

 Thank you for considering our Preliminary request.

Best,

Dandan

_______________________________________________
Star-hp-l mailing list
Star-hp-l AT lists.bnl.gov
https://lists.bnl.gov/mailman/listinfo/star-hp-l