sPHENIX bulk physics topical group

["Perepelitsa, Dennis" <dvp AT bnl.gov>]

Hi Ejiro and all,

Thanks for the fast response to Ron.

I note that the run you are using is one of the earlier ones with a very off-center z-vertex distribution. So even with a z-vertex cut of |z| < 20, the types of events being selected are not representative of what they would be in a nominal run centered at zero (i.e. the acceptance of the MBDs is effectively different). The multiplicity-dependence of the z-vertex distribution must also be playing a role, although I’m not sure how big in this particular case.

Have you compared the EP flattening procedure & resulting resolution in a run we took after the beam spot re-centering (run number >20300)? How quickly could that kind of check be done? 

Dennis

On Feb 9, 2024, at 7:10 AM, Brennan Schaefer <brs521 AT lehigh.edu> wrote:

Hi Ejiro, et. al,

In all four flattening plots of the North and South MBD, with and without the shift, there seems to be a dip around 0 (rad?).  If the identical procedure is used later on, it will influence anisotropy measurements, etc.

best,

b

On Fri, Feb 9, 2024 at 8:34 AM Ejiro Umaka <ejironaomiumaka AT gmail.com> wrote:

Hi Ron,

I added a z-vertex cut and addressed your recommendations. The new note is attached.

Thanks,

Ejiro

On Thu, Feb 8, 2024 at 10:19 PM Ron Belmont <belmonrj AT gmail.com> wrote:

Hi Ejiro,

I don’t think it’s a good idea to publicly show an event plane distribution *without* a z-vertex cut.  How quickly can you reproduce the result including a z-vertex cut?

Regards,

Ron

-----------------------------------------------------------------------------
Ron Belmont (he/him/his)
RHIC/AGS Users' Executive Committee
Assistant Professor, Department of Physics & Astronomy
University of North Carolina at Greensboro
-----------------------------------------------------------------------------

On Feb 8, 2024, at 10:06 PM, Ejiro Umaka <ejironaomiumaka AT gmail.com> wrote:

Dear all,

I would like to seek approval for 2 plots showing the calibration steps of the MBD event plane angles in run 2023 commissioning data. The plots can be seen in the note attached. These plots will be used to discuss the event plane calibration process in my talk at WWND24.

Regards,

Ejiro

 

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--

Brennan Schaefer

Postdoctoral Research Associate

Physics Department

Lehigh University

Bethlehem, PA 18015, USA

402 Lewis Laboratory

tel: 610.758.5328

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Dennis V. Perepelitsa
Associate Professor, Physics Department
University of Colorado Boulder