sPHENIX is a new detector at RHIC.

[Ralf Seidl <rseidl AT rcf.rhic.bnl.gov>]

Dear All,

since the meeting time makes it impossible to attend these general 
meetings, I thought I comment briefly on the minutes with regards to the 
Medium Energy program:

> * sPhenix and DOE medium energy program: it was suggested not to use
> medium energy funding to sPhenix
> ASKED TO US: Prepare short document: focus on the detector. Needed to
> educate DOE NP about the importance of the spin program
> c(Jaime): Be careful: The spin is a longitudinal program. Some physics
> will be completed also by STAR upgrade.
> HOMEWORK: Further discussion on how to present this note successfully
> and soon (in one or two weeks)
> c(Nils): In the original proposal, we have looked at the forward region
> not the central. They are asking for central program. We need more time
> to think about it.
> c: The time scale is not specified
> c(Gunther) In CD0 there was no spin physics program
> c(Dave) Medium energy can not fund the barrel
> c(Gunther) We need to clarify an strategy
> ACTION: Conveners will meet to discuss about this note

Jamie is quite right, that much of the medium energy measurements at 
mid-rapidity are indeed already being pursued by STAR. As such we would 
need to show for many of the ALL measurements, how much smaller the 
uncertainties would become using the high-rate capabilities of sPHENIX. 
The problem is, that you are statistics limited at high Pt or dijet 
masses where the gluon spin is best-known while the lower-x where it is 
less known lie at higher energies, forward and start to be systematics 
limited. I think the traditional direct photon and photon-jet ALLs would 
be good to emphasize though  as they are always statistics limited. 
Those are not unique but a good cross check of the previous measurements 
and a very clean channel. In a similar direction, and given the 
excellent electron capabilities, electron DY ALLs might be also an 
interesting option for the ubar helicities.
Nuclear PDFs and nuclear fragmentation functions are something where 
sPHENIX could make a big impact as the access to gluon nPDFs/FFs is 
essentially unique to RHIC/LHC. STAR has data taken in Run15 but given 
that at the moment very little is known about both of them this data 
would be very valuable. I suggest that one could concentrate on this 
aspect in the write-up with the main measurements the various jet,di-jet 
(and DY?) RpAs and the hadron-in-jet FFs for pp and pA.
Joe's correlation measurements should also be continued for di-jets and 
photon-jets, but since their interpretation is very unclear to the 
community I would refrain from advertising them too much.

Cheers,

Ralf