STAR Flow, Chirality and Vorticity PWG

[Sergei Voloshin <voloshin AT wayne.edu>]

Hi Diyu,

If the efficiency dependence on the decay topology (parameterized in my presentation as a function of phist-phi) is known, indeed one can use proper weights to eliminate the effect (or just calculate the corrections). How to calculate the efficiency,  is a separate question. Just the distribution in phist-phi, which you suggest to use, besides the efficiency would also depend on the signal itself (both spin alignment and flow), thow I expect this dependence to be small. My approach/hope, which I did not discuss in this presentation, would be to measure 3 quantities, let us call them "observed": drho_obs, v2_obs, a2_obs, and having the corresponding relations between them  (shown in slide 9 + a similar relation for v2_obs) extract the "real" drho, v2 and a2.

Thank you for comments/question,

regards,

Sergei

On Thu, Apr 13, 2023 at 6:16 AM dshen <dshen AT rcf.rhic.bnl.gov> wrote:

Hi Sergei,

Thanks for sharing your slides.
I have a quick comment, it seems doable to me but has to be confirmed.
In your slide 9, efficiency contributes to spin alignment in the way of
non-zero a2, which means the efficiency is not isotropic as a function
of \phistar - \phi. I am wondering if we use the inverse of counts in
each \phistar - \phi bin as a weight, we are able to eliminate this
effect, aren't we?

Thanks,
Diyu


On 2023-04-13 09:57, Sergei Voloshin via Star-fcv-l wrote:
> Hi all,
>
> I have done some (MC) studies on the interplay of tracking efficiency,
> flow and SA and its effect on corresponding measurements.
>
> I was not able to present this study at FCV (not yet, probably next
> time), so I put some results in the presentation (start from page 5)
>
>
> https://www.star.bnl.gov/protected/bulkcorr/voloshin/voloshin_SpinAlgnAcceptance.pdf
>
> If interested, have a look. Any comments are very welcome.
>
> Best regards,
> Sergei
>
> --
>
> ======================================
>  Sergei A. Voloshin
>  Professor of Physics,  Wayne State University,
>  666 W. Hancock,  Detroit,  Michigan,  48201
>  e-mail: sergei.voloshin AT wayne.edu
>  Phone: 1-313-577-1630;  Fax: 1-313-577-0711
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--

======================================
 Sergei A. Voloshin
 Professor of Physics,  Wayne State University,
 666 W. Hancock,  Detroit,  Michigan,  48201
 e-mail: sergei.voloshin AT wayne.edu
 Phone: 1-313-577-1630;  Fax: 1-313-577-0711     
======================================