STAR HardProbes PWG

[Kikoła Daniel <Daniel.Kikola AT pw.edu.pl>]

Hi Issack,

> 1) Your 2016 topological reconstruction cuts are centrality-dependent
> but your analysis is for the full 0-80% range. Do you just average
> the values from the 5 different ranges, or do you perform the
> analysis in these 5 separate ranges and then add them all together?

We apply D0 reconstruction cuts as a function of centrality, but then
fill one set of raw Delta phi histograms (for F(D0)xF(D0bar),
F(D0)xB(D0bar), F(D0bar)xB(D0), B(D0)xB(D0bar)) for 0-80% events. Then,
we perform the final stages of the analysis using the centrality-
integrated distributions.
Thus, the results are effectively biased towards central collisions,
where the chance of finding a pair of D-meson candidates is higher.
Applying efficiency as a function of centrality and pT removes this
bias, but with the current statistics, it does not change the physics
conclusions.

> 2) I think Yi asked this in a meeting once, but I can’t remember the
> answer: why do you have a large uncertainty from the side-band
> background selection variation for Delta-phi of 0.31, but zero
> contribution to the other four? Seems strange to me.

This is a consequence of applying the "Barlow approach"
(https://urldefense.com/v3/__https://arxiv.org/abs/hep-ex/0207026__;!!P4SdNyxKAPE!B7mzEuTCbAB89yH0M5TOhkm58eaS-Cqexy_fzyl5lV600vgpwBd62fp-A3rgLnuCeS5NJkzbCxKbgvlb-EADUI34yni0-igVNA$
 ) to systematic uncertainty
estimation with an arbitrary threshold. I set the threshold of 2sigma
as a limit for possible statistical fluctuation, and only for one bin I
got an effect larger than 2 sigma (please see slide 25 in
https://drupal.star.bnl.gov/STAR/system/files/D0-corr-AuAu200GeV-preliminary-request-16-08-2023.pdf
)

For the first bin, we have a 2.25 sigma difference between B1+B2 vs B1
background selection cases. It could still be a statistical fluctuation
since 2.25 sigma is not a significant effect. However, with the pre-set
threshold of 2 sigma, I took this as a systematic error.

Alliteratively, we could take the max. difference of B1+B2 vs B1 and
B1+B2 vs B2 as systematic uncertainty for all Delta phi bins, or drop
the uncertainty due to side-band background selection variation for the
first bin.

Best regards,
Daniel




On Thu, 2023-08-31 at 00:16 +0000, Mooney, Isaac wrote:
> Hi Katarzyna and Daniel,
> 
> The preliminary proposal looks good to me. I have two small
> questions, probably naïve.
> 
> 1) Your 2016 topological reconstruction cuts are centrality-dependent
> but your analysis is for the full 0-80% range. Do you just average
> the values from the 5 different ranges, or do you perform the
> analysis in these 5 separate ranges and then add them all together?
> 
> 2) I think Yi asked this in a meeting once, but I can’t remember the
> answer: why do you have a large uncertainty from the side-band
> background selection variation for Delta-phi of 0.31, but zero
> contribution to the other four? Seems strange to me.
> 
> Thanks!
> -Isaac
> 
> > On Aug 28, 2023, at 4:16 AM, Yi Yang via Star-hp-l
> > <star-hp-l AT lists.bnl.gov> wrote:
> > 
> > Dear Katarzyna and Daniel,
> > 
> > Thanks a lot for the prompt reply. Looking forward to seeing the
> > updated request. 
> > 
> > Cheers,
> > Yi
> > 
> > 
> > On Mon, Aug 28, 2023 at 5:13 PM Kikoła Daniel
> > <Daniel.Kikola AT pw.edu.pl> wrote:
> > > Dear Yi,
> > > 
> > > In addition to Katarzyna's response: we can estimate how much
> > > data we
> > > would need to observed a correlation signal in Au+Au, assuming
> > > the same
> > > reconstruction efficiency and a given level of stat. precision
> > > (for
> > > example 0.2).
> > > 
> > > Best regards,
> > > Daniel  
> > > 
> > > 
> > > 
> > > -- 
> > > Daniel Kikoła
> > > Faculty of Physics,
> > > Warsaw University of Technology
> > > Koszykowa 75
> > > 00-662 Warsaw
> > > (+48) 22 234 5851
> > > 
> > > On Mon, 2023-08-28 at 08:33 +0000, Gwiździel Katarzyna (DOKT) via
> > > Star-
> > > hp-l wrote:
> > > > Dear Yi,
> > > >  
> > > > We have done some predictions for measurement of angular
> > > > correlations
> > > > of charmed mesons at RHIC.
> > > > We came to the conclusion that the successful study of
> > > > azimuthal
> > > > correlations of charmed mesons 
> > > > should be possible in STAR using combined data from run 2017
> > > > and
> > > > 2022.
> > > >  
> > > > When it comes to simulations. We compared the experimental
> > > > result
> > > > with the p+p baseline obtained with Herwig++. 
> > > > Daniel included this on his slides.
> > > >  
> > > > I hope this addresses your concerns.
> > > >  
> > > > Best regards,
> > > > Katarzyna
> > > > Od: Star-hp-l <star-hp-l-bounces AT lists.bnl.gov> w imieniu
> > > > użytkownika
> > > > Yi Yang via Star-hp-l <star-hp-l AT lists.bnl.gov>
> > > > Wysłane: poniedziałek, 28 sierpnia 2023 08:09
> > > > Do: STAR HardProbes PWG <star-hp-l AT lists.bnl.gov>
> > > > DW: Yi Yang <yiyang0429 AT gmail.com>
> > > > Temat: Re: [Star-hp-l] D-Dbar azimuthal correlations in AuAu
> > > > 200 GeV
> > > > - analysis update and preliminary figure request
> > > >  
> > > > Dear Daniel,
> > > >  
> > > > Thanks a lot for the preliminary request. 
> > > > Everything looks good to me. 
> > > > I am wondering if you can predict how much more data you need
> > > > to see
> > > > this correlation? If so, it would be nice to add in the
> > > > slides. 
> > > > I also remember someone (Rongrong?) suggested that mentioning
> > > > what we
> > > > expect to see from the simulation will be a good idea. You can
> > > > also
> > > > consider it. 
> > > >  
> > > > Cheers,
> > > > Yi
> > > >  
> > > >  
> > > > On Thu, Aug 17, 2023 at 2:25 PM Kikoła Daniel via Star-hp-l
> > > > <star-hp-l AT lists.bnl.gov> wrote:
> > > > > Dear All,
> > > > >  
> > > > > Time permitting, we would like to present a short analysis
> > > > > update
> > > > > on
> > > > > the D-Dbar azimuthal correlations in AuAu 200 GeV at the
> > > > > meeting
> > > > > today
> > > > > and discuss the preliminary figure request for this study.
> > > > >  
> > > > > Here are the slides for the presentation:
> > > > >  
> > > > > https://drupal.star.bnl.gov/STAR/system/files/D0-corr-AuAu200G
> > > > > eV-preliminary-request-16-08-2023.pdf
> > > > >  
> > > > > Best regards,
> > > > > Daniel and Katarzyna
> > > > >  
> > > > > _______________________________________________
> > > > > Star-hp-l mailing list
> > > > >  Star-hp-l AT lists.bnl.gov
> > > > >  https://lists.bnl.gov/mailman/listinfo/star-hp-l
> > > 
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> 

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