# P5 Report

A new P5 report is out, and being discussed at the HEPAP meeting in Washington today. The charge to P5 was to develop tentative 10 year plans for US HEP, under 3 scenarios:

• Scenario A: funding at the current post-budget cut level of $688 million for the DOE. • Scenario B: funding at the pre-budget cut (2007) level of$752 million for the DOE.
• Scenario C: a doubling of the budget over 10 years, starting from the 2007 level.
• This report updates earlier ones and the EPP2010 report in light of new realities, specifically acknowledgement that the cost of the ILC means it’s not happening anytime soon, and the grim budget situation caused by the recent budget cuts for this year. To be honest, it’s very unclear to me how anyone can sensibly carry through this kind of exercise right now. With the supplemental appropriation still up in the air at the House and the Senate, it’s hard to know what the US HEP budget will be next month, much less next year, or over 10 years. The LHC startup is only months away, and how long that takes and what the LHC shows are crucial things for any future planning.

In the report, the field is broken into three parts:

• The Energy Frontier: experiments at the highest possible CM energies. This is the Tevatron now, the LHC soon, and a possible electron collider later.
• The Luminosity Frontier: experiments at the highest possible event rates. This include neutrino experiments and searches for rare decays. The proposed “Project X” at Fermilab is the main possible new machine here.
• The Cosmic Frontier: astro-particle physics studies of dark energy and dark matter, study of astrophysical sources of high energy particles and neutrinos.
• One crucial decision that will need to be made soon is how long to run the Tevatron. The report says to continue support “for the next one to two years”, with two only in the optimistic scenario C. On the question of the ILC, the report describes “a wide range of opinion” in the HEP community and on the panel. Opinions about both of these may very well change over the next year depending on what happens at the LHC.

In both scenarios A and B, the report envisages cutting staff at the national labs, in favor of preserving support for research based at universities.

Update: Science magazine this week has two excellent articles by Adrian Cho, about the problems facing Fermilab, and the ILC.

Update: The final P5 report is here.

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### 5 Responses to P5 Report

1. wb says:

RE: “The Energy Frontier: … a possible electron collider later.”

While the VGs of the report maintain a possibility for an ILC, they do by implication raise the distinct probability that the energy of the ILC is wrong and therefore the technology is wrong. If that is so one of the justifications for Project X as so late a date (compared with J-PARC) is cut away. Hence, it would have been helpful if the report specifically stated that research should be increased to determine if a consistent end-to-end concept for a muon collider is possible. Instead we have in Scenario C, “If another lepton collider technology is found to be preferable, its R&D would be advanced.” One can certainly read support for muon collider R&D that into the words, but not necessarily. The words could just mean CLIC – no sure thing as a concept. In recommendations more explicit language would have been preferable.

The report seems to make the future of Fermilab – as a single purpose HEP accelerator lab – contingent on a vigorous program at DUSEL. Otherwise and for the most part Fermilab seems to be reduced to playing a supporting role in HEP. Ah, yes, but it is the leading supporting role in the US. Perhaps that is what “maintain a leadership role in world-wide particle physics” means.”

The report of the report cannot be considered an endorsement of the strategic plan for Fermilab presented at the last HEPAP meeting. Particularly for Scenario A: “Constant level of effort at FY2008” the panel sidesteps the obvious but crucial question, “at that funding level does the US need a single purpose HEP laboratory?” I admit that were I on the panel I would also have ducked the question. Especially since the Panel admits that Scenario A “would sharply diminish the US capability in particle physics from its present leadership role;” the most likely scenario next year is inconsistent with the panel’s primary recommendation, “maintain a leadership role in world-wide particle physics.”

To be sure one must wait to read the entire report before one understands all the implications. It is easy to be critical and not so easy to be constructive in so highly constrained a situation. The Panel was dealt a poor hand to play.

My bottom line is that we need to make every effort to get results out of LHC as early as possible. Only compelling results from LHC are going to change a grim picture for accelerator based HEP.

2. Peter Shor says:

I don’t believe the scientists looking at data from the LHC are going to rush things to try to get the next generation of particle accelerators scheduled sooner, nor do I believe that this is a particularly good idea. We’ll just have to wait and see what these results are, and try somehow not to lose expertise in buliding particle accelerators in the meantime.

3. wb says:

My point about LHC was not about “rushing to Judgment” at the LHC, but about the 1) importance of a very strong US commitment to the LHC physics program, 2) the value of a faster rather than slower sociological process in the ATLAS and CMS collaborations. Investment choices may well have to be made on far less than discovery-level data for a vigorous accelerator-based program beyond LHC-1. Even preliminary hints as to energy scales is critical to decisions over the next 3 – 4 years concerning the suitability of the technology choice for a linear collider.

There is no question that Europe and Asia will maintain a high level of expertise in accelerator science and technology throughout the next decade. The prospects for the US in general and Fermilab in particular are not so sanguine.

4. srp says:

Relatively small amounts of money (but a multiple of what is spent today) could be allocated to advanced accelerator concepts to determine whether they were feasible. Before deciding about next-generation accelerators of conventional design (and hence no improvement in energy), common sense suggests first spending a little bit of money to determine if advanced machines could/should be built instead.

If the answer from such investigations were yes, then it would be much easier to get the money for an operational machine because the jump in energy would at least offer the potential for fundamentally new results. Exciting new technology that opens up new frontiers is much more likely to attract support than giant installations that don’t move the needle very much.

If the answer about advanced concepts were no, then the sorts of incremental but hugely expensive projects currently under discussion could be put forward. I wouldn’t be optimistic in this latter case, but at least the alternatives would have been explored and ruled out.

The stubbornness (or lack of vision) of the community in obstinately putting forward these high cost/benefit incremental accelerator concepts, without seriously trying to get out of today’s energy dead end, is very disappointing. It’s almost as though people are more concerned with a steady flow of jobs than with maximizing the rate of discovery. But the public and its representatives are not likely to fund these conventional concepts–the scientific return per dollar invested just seems too low. Any new accelerator is going to have to make a compelling case that it can do much more than the LHC.

5. Peter Shor says:

If high-energy physicists try to make a snap decision on the energy level and usefulness of a followup to the LHC, spend a large amount of money on this followup, and then are proved to be wrong by further analysis of data from the LHC, I strongly suspect the damage to physics will be far greater than that incurred by waiting until definitive results are out from the LHC.

I have no objections to spending relatively small amounts of money in a planning phase for the next accelerator.