STAR HardProbes PWG

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

Hi Barbara, All,

Regarding the femtoscopy and in-medium interactions, there are two
points we consider:

1. The femtoscopic correlations provide information about the so-called
length (or region) of homogeneity. It is "the size and shape of the
phase space cloud of outgoing particles whose velocities have a
specific magnitude and direction" (please see the review by Mike Lisa
for more information 
https://urldefense.com/v3/__https://arxiv.org/abs/nucl-ex/0505014__;!!P4SdNyxKAPE!HnrLo_Dj3q7JvhRMD7X37oyS5ze5xGGGgo17dOET25MLAHtRwLIULSsXkVDypm6PeJQBTO4vD7uGOgao497x9KaKrbsuSI0yEg$
 ).

Then collective expansion (both longitudinal and transversal) reduce
the size of the region of homogeneity. Thus femtoscopy provides some
information about the collective behavior of charm quarks in the QGP.

2. The second point is naive and probably too simplistic: 

We consider that the length of homogeneity provides information about
the correlation of hadrons and charm quarks (more precisely, the
average distance between emission points of correlated particles in a
D0-hadron pair). Then one could interpret this distance as a measure of
how far the interaction between charm quarks and light quarks extends
in a medium. Thus, the study of the length of homogeneity for D0-hadron
pairs could provide some information about the distance at which the
strong interactions are screened.

Of course, the measured correlation signal will be a convolution of
dynamical effects, interactions etc., and one should have a solid model
to interpret the data. 

Unfortunately, we are unaware of model predicitons for charmed meson-
hadron fesmoscopic correlations in the heavy-ion collisions.

Best regards,
Daniel



On Mon, 2022-11-28 at 17:26 +0100, Barbara Trzeciak via Star-hp-l
wrote:
> Hi Priyanka,
> 
> thanks for the explanation. 
> Sorry for being slow on this, but I still don't get it. What kind of
> source size do you extract in this case and how does it correlate
> with the Debye screening length ? 
> Maybe you have some reference related to the D femtoscopic
> correlations so that I can educate myself more ?
> 
> Cheers,
> Barbara
> 
> On Mon, Nov 28, 2022 at 4:01 PM Roy Chowdhury Priyanka (DOKT)
> <priyanka.roy_chowdhury.dokt AT pw.edu.pl> wrote:
> > Hello Barbara and Nihar,
> > 
> > Thanks for your comments and feedback. 
> > 
> > Here's a clarification regarding the motivation of the analysis
> > (asked by Barbara). 
> > Explanation: Two-particle femtoscopic correlation is a useful
> > method to study the Debye screening length of c/cquarks within the
> > QGP medium. By fitting the analytical result into the suitable
> > model (ex. Lednicky & Lyuboshitz), source size can be calculated.
> > For strong correlation, the source size is expected lower than the
> > size of the fireball and vice-versa. 
> > If required, I can add this explanation to my abstract.
> > 
> > Regarding the suggestion by Nihar, " relatively low momentum"
> > instead of " low relative momentum": For femtoscopic correlation,
> > 'relative momentum' (k*) is from the reference of relative momentum
> > between two particles for which pair we calculate correlation
> > function C(k*). 
> > 
> > I tried to address all your suggestions. Please check my modified
> > abstract attached here. 
> > 
> > Regards,
> > Priyanka
> > 
> > 
> > 
> > From: Star-hp-l <star-hp-l-bounces AT lists.bnl.gov> on behalf of
> > Nihar Sahoo via Star-hp-l <star-hp-l AT lists.bnl.gov>
> > Sent: Sunday, November 27, 2022 12:16 PM
> > To: webmaster AT star.bnl.gov <webmaster AT star.bnl.gov>; STAR
> > HardProbes PWG <star-hp-l AT lists.bnl.gov>
> > Subject: Re: [Star-hp-l] STAR presentation by Priyanka Roy
> > Chowdhury for Hard Probes 2023 submitted for review
> >  
> > Hello Priyanka,
> > 
> > Please find my comment on your nice abstract.
> > 
> > Title: drop "registered"
> > 
> > "Due to their large mass, charm quarks.." -> "Due to large mass,
> > the 
> > charm quarks…"
> > "…the created system, including…" -> "the created medium— the Quark
> > Gluon Plasma."
> > "at low relative momentum…" -> " …at relatively low momentum…"
> > 
> > Please mention about the kinematic range of D-meson and hadrons;
> > what 
> > centrality, analysis details, etc.
> > 
> > 
> > Cheers
> > Nihar
> > 
> > On 2022-11-21 20:01, webmaster--- via Star-hp-l wrote:
> > > Dear Star-hp-l AT lists.bnl.gov members,
> > > 
> > > Priyanka Roy Chowdhury (priyanka.roy_chowdhury.dokt AT pw.edu.pl)
> > > has 
> > > submitted
> > > a material for a review, please have a look:
> > > https://drupal.star.bnl.gov/STAR/node/61809
> > > 
> > > Deadline: 2022-12-05
> > > ---
> > > If you have any problems with the review process, please contact
> > > webmaster AT www.star.bnl.gov
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-- 
Daniel Kikola
Faculty of Physics,
Warsaw University of Technology
Koszykowa 75
00-662 Warsaw
(+48) 22 234 5851