Comments received January 25
I share the worries Tony expressed in his comments. The current organization of the bullet items in (1) separates detector upgrades and luminosity upgrade. As detailed in the RHIC-II white paper both go hand in hand. We can only fully exploit the detector upgrades with increased luminosity. I don't think that splitting them this way is a good choice. In my opinion the way it was expressed in the version we had on the board in
Rutgersbefore we all left was very well done. It was my understanding that we all agreed on that: a comma separated list with RHIC running, detector upgrades and luminosity upgrades. All are equally needed to achieve the central goal as defined in the first sentence.
I'm also a bit worried about a certain imbalance in details between item 1 (RHIC) and 2 (LHC). While we are very detailed on (1) and even to some degree in (3), (2) is rather vague. Significant and timely is fine with me but I wonder if leaving it as it is, leaves too much room for interpretation. I understand that we do not want to be too specific since this might haunt us later but being to vague might also fire back. I leave this up to those that are involved in the LHC program; this is just an observation.
Comments received January 24
I would like to suggest that the LHC bullet (to be realized) be moved into the all-encompassing bullet number 1. It should appear as the second sub-bullet. The theory is applicable to both and would be appropriate after RHIC and LHC sub-bullets. I fear that in the present formulation, the LHC investment will not have sufficient priority nor be timely enough to happen before it is too late.
If you disagree with putting "all the eggs in one basket" (which I worry about), we should move all the sub-bullets of number 1 out as real numbered bullets, with the LHC experiment behind RHIC experiment.
I would like to suggest one change. I propose that you change the first bullet in section 3 about the EIC from:
"Precision mapping of the sea-quark and gluon landscape in a nucleon to clarify its spin and flavor structure"
"Precision mapping of the quark and gluon landscape in nucleons and nuclei to clarify their spin and flavor structure"
My reasoning is that one of the main arguments for the EIC is that there are no measurements of quark structure functions (best done with DIS) in nuclei as a function of impact parameter and only 1 attempt that I know of (E665-ZPC65, 225-244 (1995). I speak as one of the people who made the first one of these measurements (at BNL-see Proc. 6th Symp. Elec. Phot. 1973, p311) 5 years after DIS was discovered in e-p scattering at SLAC. Regarding gluon structure function measurements, first of all there are no measurements in nuclei. Also, for decades (since 1979) very few hadron oriented people believed in the indirect measurements of the gluon structure function of the proton from DIS and preferred direct photon production in p+p collisions which gives a direct measurement from g+q--> gamma+q if the quark structure functions are known (from DIS). Of course this can easily be extended to p+A collisions with impact parameter measurement. More recently photoproduction, gamma+g-->c +c-bar (which can be done at EIC both in protons and nuclei) provides a direct measurement of the gluon structure function if pT is large enough to be in the perturbative region (which it isn't at fixed target facilities, so far).
With reference to sea-quark measurements, it is my opinion that the best, if not the only measurements come from Drell-Yan production q+q-bar--> mu+ mu- in p-p and p-A collisions. Also we intend to do this in p-p collisions at RHIC using W production. Hence, I can't imagine why you list sea-quark measurements as one of the arguments for the EIC rather than just quarks.
Comments received January 23
A quick suggestion - Point #1, 2nd bullet, 2nd line: insert "baryon" between "finite" and "density".
Here is some input on the
- The authors of the EIC science overview paper (Antje Bruell, Rolf Ent, Abhay Deshpande, Raju Venugopalan and myself) propose to change the draft of the first physics bullet in the EIC recommendation to read
`Precision imaging of the sea-quarks and gluons to determine the spin, flavor and spatial structure of the nucleon'
I read the revised version of this just posted by the RHIC folks. I'm happy with what is written as far as intent. However, I am still worried about the second bullet about theory under the first topic. It is not that I don't agree with the focus, but instead that I worry that any phrasing that could be interpreted as "more money for the same area of work" may meet with a tepid, or worse, reception at the agencies. I think the present phrasing just needs to be made a little more precise. I suggest re-casting just a bit to affirm support for current endeavors and then propose increases for the new opportunities. What I am thinking is along the lines of
"Continued support for the ongoing theoretical studies of QCD matter, finite temperature and finite density lattice QCD studies, and an increase of funding to support new initiatives now possible, for example those which combine phenomenological mmodeling and data analysis."
I think the last phrase has to be an example of what new funding could support. I realize one doesn't want an argument to break out that only a certain targeted area should be a beneficiary of any new support that could come.
I'm in part reacting after watching many Long Range Plans since 1983 ask for more operating money but the only real increases going to new initiatives. New initiatives don't have to be machines and detectors, since after all INT was the one new initiative from the 1987 NSAC Theory Report ("Koonin report") that Dave Hendrie said was straightforward to guide thru DOE, OMB and Congress. SO let's have a new initiative in theory, and let's stress that this has just now become possible because of the confluence of data in hand to influence thinking (we did not discuss sQGP at the time of the 2002 LRP, after all), technical developments in theoretical methods and tools, and the advance in scientific understanding generally, that we realize there is a new opportunity in theory if we can only have the resources to address it.
Comments received January 22
The rewritten recommendations are fine as they read. However, I believe they are weaker ones as stated than the general momentum at the meeting for focusing on studying the glue. The glue as the medium that holds quarks together, but also as QCD matter itself. Then from this thrust follows the study of the QGP etc. as stated, and other manifestations of glue. It seems to me that an explicit focus on the glue presents a grander, more impressive goal.
I think the recommendations are very well written and reflect the sentiment of the town meeting. I also like the bullets in the first recommendation, which separate the detector and luminosity upgrades and put them in the correct order of importance. Also the theory bullet is fine as it is.
The only small suggestion I have is to find a better word for "qualitative" in the first sentence "Our central goal is a QUALITATIVE advance in our understanding of QCD Matter, through quantitative ..." Maybe "substantial" or something like that is a better choice. "Qualitative" in the meaning of "not quantitative" is exactly what we want to get away from... I know this is not the intended meaning, but at first sight I got confused by this.
The prioritized bullets read well and make very good sense. They do a good job of summarizing the case. However I have one specific concern:
The first bullet has three sub-bullets, which are a package of items that are all essential for a successful program. I agree completely with the intended message. But I am somewhat concerned that they might be read as implying that the RHIC II luminosity upgrade, by far the most expensive, is lower in priority than the first two - rather than being crucial to our ability to capitalize on them, and crucial to the relevance of the RHIC program after the LHC turns on. This is clear to us, but it is not obvious to nuclear physicists outside our field.
Having said that, putting the RHIC II upgrade first would destroy the nice flow of the three sub-bullets, so I do not suggest that. It may be that the words that support these bullets can make it clear that the future of the RHIC program would be severely limited without the luminosity upgrade. Another possibility is to add some words to the RHIC II sub-bullet so that it reads something like:
"The RHIC II luminosity upgrade, to provide access to the low cross section processes required for these quantitative studies."
The intent would be to make it less easy for the reader to decide that 2 out of 3 would be pretty good :) .