STAR HardProbes PWG

[Yi Yang <yiyang0429 AT gmail.com>]

Hi Priyanka,

Are you coming to the preQM tomorrow? It will be good if we can discuss some details in person.

Cheers,

Yi

On Thu, Aug 31, 2023 at 3:37 PM Roy Chowdhury Priyanka (DOKT) <priyanka.roy_chowdhury.dokt AT pw.edu.pl> wrote:

Hi Yi, Barbara,

Here is my explanation about the comparison plots before and after purity correction (slide no. 20).

1. Plot heading/titles are incorrect, it should be D0-K instead of D0-Pion. I double checked the data I used for the plots.
2. There are statistical uncertainties present before purity correction but very small. Two plots separately are attached here (both are for standard topological cut).

- About the D0 p, how do you get it? And how did you translate the D0 purity from as a function of pT to as a function of p? 

• If you are referring to D0 purity, then it's simply signal/signal+background ratio combined with weighted average and variance. I didn't translet D0 purity from a function of pT to function of p (momentum) because D0 topological cuts have pT dependence. As Kaon are primary tracks, so we consider p (momentum) instead of pT and took an average purity value with a kaon momentum cut < 1 GeV/c

Regarding your comment on considering kaon purity as 3% and pair purity or overall relative uncertainty 10%, I don't have a good expalanation right now. I will try to find a satisfactory answer by tomorrow morning.

Regards,

Priyanka

---

From: Star-hp-l <star-hp-l-bounces AT lists.bnl.gov> on behalf of Yi Yang via Star-hp-l <star-hp-l AT lists.bnl.gov>
Sent: Thursday, August 31, 2023 7:55 PM
To: Kikoła Daniel <Daniel.Kikola AT pw.edu.pl>
Cc: Yi Yang <yiyang0429 AT gmail.com>; star-hp-l AT lists.bnl.gov <star-hp-l AT lists.bnl.gov>
Subject: Re: [Star-hp-l] Preliminary figure request for D0-K femtoscopic correlation

 

Hi Priyanka and Daniel,

Thanks a lot for the prompt response. 

I have some follow-up questions: 

  - The 1st and 2nd bullets from Barbar are referring to the attached plot. You can see on the title it says "D0-pion", and there is no (or extremely small) statistical uncertainty on the black points (uncorrected). We are wondering why the statistical errors become significant after the correction (red points). 

  

 - About the D0 p, how do you get it? And how did you translate the D0 purity from as a function of pT to as a function of p? 

 - Regarding the Kaon purity, I would think larger uncertainty is needed based on the fit results, 3% will be underestimated, to me. 

 - Regarding changing the dataset, it needs to be clear that you only use 2/3 statistics on p.7. 

 

 - Regarding the 10% pair purity, I think it is kind of arbitrary, anything can support this 10%?

Cheers,

Yi

  

On Thu, Aug 31, 2023 at 12:01 PM Kikoła Daniel <Daniel.Kikola AT pw.edu.pl> wrote:

Hi Yi and Barbara,

For the purity of the kaon sample: I fully agree that the dE/dx fits
require more work. The current results was a first look at the data to
check if kaon identification with ToF mass provides good purity, and it
turned out we need to pay more attention to this quantity.

The value quoted by Priyanka (purity = 0.97 +/- 0.03) was selected to
cover the purity variation we have seen for momentum p < 1 GeV in the
first look at the dE/dx fits, and to have symmetric uncertainties for
error propagation to the correlation function. 

Admittedly, this is a crude method, and we will work to improve it.

Best regards,
Daniel

--
Daniel Kikoła
Faculty of Physics,
Warsaw University of Technology
Koszykowa 75
00-662 Warsaw
(+48) 22 234 5851

On Thu, 2023-08-31 at 11:07 -0500, Yi Yang via Star-hp-l wrote:
> Hi Priyanka,
>
> Thanks a lot for the preliminary request. I have some
> comments/questions for your consideration. 
>  - I shared the same confusion as Barbara, could you please
> clarify them? I am also surprised that the 3% uncertainty based on
> the fit in your study slides. Could you please tell us more about
> it? 
>  - I am confusing myself a bit when I read your request, could you
> please tell me how you get the reduced p for D0? 
>
>  Regarding the request: 
>  - Please add your advisor's name and email to the slide. 
>  - From your poster, you mentioned 2016 data, but now I think you
> only concentrate on the 2014 data, right? If so, please change your
> poster. 
>  - p10: could you please summarize the standard, loose, and tight
> cuts in a table (or readable format, instead of coding style)? 
>  - Preliminary plot: 
>      - central --> centrality 
>      - remove the box around "Au+Au, STAR" and change it to "data"  
> (you have Au+Au in the bottom) 
>      - you can try to use "boxes" for the systematics instead of
> "parentheses" since some bins look strange (0.03, 0,17, 0.27).  
>      - physics message: I agree with Barbara that we should say "It
> is consistent with no correlation with current statistics (2014)".
> You can mention the potential by adding 2016 data in your poster.    
>  
>  
> Cheers,
> Yi
>
>
> On Thu, Aug 31, 2023 at 10:20 AM Barbara Trzeciak via Star-hp-l
> <star-hp-l AT lists.bnl.gov> wrote:
> > 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
> > _______________________________________________
> > Star-hp-l mailing list
> > Star-hp-l AT lists.bnl.gov
> > https://lists.bnl.gov/mailman/listinfo/star-hp-l
> _______________________________________________
> Star-hp-l mailing list
> Star-hp-l AT lists.bnl.gov
> https://lists.bnl.gov/mailman/listinfo/star-hp-l