STAR HardProbes PWG

["Roy Chowdhury Priyanka (DOKT)" <priyanka.roy_chowdhury.dokt AT pw.edu.pl>]

Hi Barbara,

Thanks for your questions. Here are my responses.

1. Why does your correlation function have no statistical uncertainties before the purity correction and has sizable uncertainties after the correction ?
   

• I calculated statistical uncertainties and put the condition if systematic uncertainty (for both loose and tight cuts) is > statistical errors then plotted as the first check (please see the plot attached here). But for the final plot, I didn't draw those (green & blue brackets). On the final plot, the blue vertical lines with horizontal bars on two ends show the statistical uncertainties of data points with standard topological cuts.

2. Also the plot says D0-pi pairs but I thought you wanted to approve the D0-K correlation function

• I don't understand here which plot you mentioned. Both the STAR data plot and the ref prediction plot are for D0-K pairs

3. Also, I don't see any uncertainties on your kaon purity plot, so I don't understand how it can influence your statistical uncertainty.

• I used the pair purity for purity correction of correlation function (formula on slide no. 20) where D0 signal purity and kaon purity was multiplied. That's how the uncertainty in estimation of purity could influence the correlation value or the total systematics.
  

4. The purity is up to 1 GeV/c, what do you assume for the higher pT range

• As we take the avarage purity value ~ 97%, to implement this, I used kaons for pairing, with momentum < 1 GeV/c. There's a TYPO (now I can see) on the requested plot. I will correct the label as Pk < 1 GeV/c

5. how 3% uncertainty was evaluated here?

• As we considered kaon purity = 0.97 +- 0.03 (systematic), (please see slide no. 13, Daniel's presentation), that's how the 3% comes. We didn't consider kaons with higher p from the overlap region
  
• We took D0 purity for each pT bin (0-1, 1-2, 2-3, 3-5, 5-10) and multiplied with the average value of kaon purity to calculate the pair purity

6. Do you have any Kaon pT selection in the data analyses ? 

• Yes, we put momentum < 1 GeV/c cut to select kaons to pair up with D0 in order to calculate correlation function

7. How do you have 10% on the pair purity ? 

• We assumed 10% uncertainty as systematic for D0 signal purity calculation (which is a safe assumption we think) 

8. do we know that the correlation function is not modified in HI compared to pp ? 

• We aren't sure about that but from comparison, we can see my correlation is ~ or < 0.9, which indicates R ~ 5 frm or large. It's a soft conclusion but obviously we need proper model study to make exact conclusion

I hope I have answered all of your doubts. Please let me know if you have any further questions.

Regards,

Priyanka

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From: Star-hp-l <star-hp-l-bounces AT lists.bnl.gov> on behalf of Barbara Trzeciak via Star-hp-l <star-hp-l AT lists.bnl.gov>
Sent: Thursday, August 31, 2023 5:20 PM
To: STAR HardProbes PWG <Star-hp-l AT lists.bnl.gov>
Cc: Barbara Trzeciak <barbara.trzeciak AT gmail.com>
Subject: Re: [Star-hp-l] Preliminary figure request for D0-K femtoscopic correlation

 

Hi Priyanka,

I have questions on your purity correction. 

- Why does your correlation function have no statistical uncertainties before the purity correction and has sizable uncertainties after the correction ?  Also the plot says D0-pi pairs but I thought you wanted to approve the D0-K correlation function. I'm a bit confused here.  Also, I don't see any uncertainties on your kaon purity plot, so I don't understand how it can influence your statistical uncertainty.

Kaon purity: 

- how 3% uncertainty was evaluated here, I would expect that in the overlap region, at ~0.6-0.8, the sys. unc. is be large .

- The purity is up to 1 GeV/c, what do you assume for the higher pT range ? 

- And as far as I understand you use average. But do you know what Kaon pT dominates your sample ? Do you have any Kaon pT selection in the data analyses ? 

- How do you have 10% on the pair purity ? 

Physics message. I would say that the data are consistent with no correlation, rather than with any of these pp models. 

Also, you make a conclusion on the correlation source size. But do we know that the correlation function is not modified in HI compared to pp ? 

Cheers,

Barbara

On Thu, Aug 31, 2023 at 5:08 PM Barbara Trzeciak <barbara.trzeciak AT gmail.com> wrote:

---------- Forwarded message ----------

From: "Roy Chowdhury Priyanka (DOKT)" <priyanka.roy_chowdhury.dokt AT pw.edu.pl>
To: Star-hp-l <star-hp-l-bounces AT lists.bnl.gov>
Cc: 
Bcc: 
Date: Thu, 31 Aug 2023 14:19:45 +0000
Subject: Preliminary figure request for D0-K femtoscopic correlation

Dear Convenors,

I have submitted a request for preliminary label on my D0-K correlation function. My slides are here https://drupal.star.bnl.gov/STAR/system/files/QM_proposal_PreliReq_Priyanka.pdf

I updated the poster with the same figure as "fig 10" on my submitted poster draft. I will upload the new version of the poster ASAP.

Regards,

Priyanka

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