sPHENIX is a new detector at RHIC.

[Jamie Nagle <jamie.nagle AT colorado.edu>]

Hello Megan,

Thanks for posting this very nice talk in advance.    I have a few minor comments and suggestions.   Even with 25+5 minutes for the talk, the 24 slides may be a bit rushed since some have 3-4 graphs each.   One might think about what "key message" one wants to  convey to this audience -- parallel session on Quark Matter and HI.

Sincerely,

Jamie

* This first one is rather general, and that is I think sPHENIX overview speakers will be more effective if they pick out one topic they are really excited about (maybe from following up on a previous measurement, maybe from a new theory paper, maybe their group plans to work specifically on that measurement, maybe the detector you have been actively involved in, maybe a Ph.D. thesis on photon-tagged jets:   https://dspace.sunyconnect.suny.edu/handle/1951/59619) and have 2-3 slides on that subject in more detail.    You then have to shorten a couple other topics, but I think that is okay and gives the audience more of your insights.

*  slide 7 - the slide number appears to have moved to an odd place

* slide 8 - MBD has timing resolution 120 ps, what is being quoted there?   single tube, one side, what multiplicity?   Would it be good to clarify, or maybe better quote the z-vertex resolution in pp to central AuAu?

* slide 8 - since sPHENIX earlier is labeled with DOE, it might be worth pointing out the sEPD is NSF-MRI funded with Lehigh PI.

* slide 9 - this slide causes me some confusion.   By my reading, the sPHENIX DAQ is always hybrid.    One set of detectors only sends data for select triggered "events" into the "experimental hall" (across the vertical dashed line in the diagram) - those are the Calorimeters, MBD, sEPD, and ZDC if we read it out.    The other set, the tracking detectors, send all their streaming data into the "experimental hall", and only then in the DAM does one decide what to keep.     Thus, it seems awkward to say "Hybrid DAQ" for 2024; it is required at the start.

What is true is that one can take more "events" or even "all events" in principle from the DAM to storage.     I believe the BUP still has in 2024 that in addition to the physics triggered events, one could take an additional 10% of all pp events with just the tracking detectors.     I am not sure of the final implementation, but one could just have a 0.94 MHz = 9.4 MHz/10 random trigger for keeping "events" in the tracking detectors.    We might not want the MBD trigger since it covers probably less than half the pp 42 mb cross section in the new position.   That enhances the tracking only measurements (e.g., open heavy flavor) statistics in pp by about a factor of 15.     Note that these pp events will not have the MBD, sEPD global information available. 

* slide 9 - my understanding is that sPHENIX is not "building" events, and so the diagram of the switch going to a condensed set of Buffer Boxes may be mis-understood.    

* slide 10 - should a line with NSF funding time be added?    It seems like it never hurts to acknowledge the major funding agencies.

*  slide 10 - I would like to see a corrected timeline (at some point) that includes when the sPHENIX detector was originally proposed in the PHENIX Decadal Plan and then the sPHENIX science proposal was submitted and not giving an incorrect impression that work only started when sPHENIX as an upgrade to PHENIX should be called a new collaboration.

* slide 17 - I would try to avoid phrases like "precision capable of constraining theoretical parameters", instead what do these constrained parameters tell us.

* slide 18 - again just to clarify, the additional 10% streaming is only in pp and cannot buy much in AuAu since sPHENIX will trigger on almost all minimum bias events anyway.    It  is also a bit awkward to highlight down to pT = 0, and then have the non-prompt D results only go down to 2 GeV/c.

||------------------------------------------------------------------------------------------
|| James L. Nagle   
|| Professor of Physics, University of Colorado Boulder

|| EMAIL:   jamie.nagle AT colorado.edu
|| SKYPE:  jamie-nagle        
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On Mon, Aug 22, 2022 at 9:19 PM Megan Connors via sPHENIX-l <sphenix-l AT lists.bnl.gov> wrote:

Dear all,

Please find a draft of my sPHENIX overview talk for the CIPANP conference that starts next week at the link below. Comments and suggestions are welcome.

https://indico.bnl.gov/event/16750/contributions/67222/attachments/42908/72098/sphenix_CIPANP2022_connors.pdf

Thanks,

-Megan