Should funding for the Tevatron be continued?

Maybe this is better in great debates but I think the answer is more based in fact than philosophy or politics.

It would cost $35M to keep it operational until the LHC upgrade has been completed - ie, 3 years. Is it worth it?

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I think that “is it worth it” is basically a question for Great Debates rather than GQ.

Colibri
General Questions Moderator

Does the world really need two giant particle accelerators? I don’t recall anyone demanding a competing lunar landing program during the Apollo missions (though it would be quite odd if I did, since I wasn’t born yet).

There has always been international competition in particle physics. That was have the fun and challenge. They want to be the first to find the Higgs. It is a good feather in their cap to have found it.

Well, the Soviets tried.

That assumes that there is a singular goal in operating a high energy particle accelerator. In fact, there are many, many different research efforts vying for time on accelerators for a variety of different purposes. Whether or not this justifies continued operation of the Tevatron I don’t know (being far removed from high energy particle physics at this point), but it isn’t an either/or proposition. Each facility should be judged on utilization, not which one is ultimately more powerful.

Stranger

Its not possible to run the Tevatron in collider mode while simultaneously providing beam for the Nova experiment (a neutrino experiment). Beam for Nova was promised to the international community many years ago, and it would be wrong to back off from that promise now. It is also worth noting that the DOE (which funds the Tevatron) has made it clear that it believes the goal for the US in particle physics should be the intensity frontier (which basically means doing neutrino physics) rather than the energy frontier.

I personally find neutrino physics less interesting, but I can’t argue with their reasoning. The performance of the LHC has improved dramatically (the instantaneous luminosity is now higher than at the Tevatron), and LHC results are already surpassing Tevatron results in many areas. This disparity is only going to get worse as the LHC increases luminosity and beam energy.

As an American working on the LHC, I certainly wish that America were leading the world in this field, but continuing to run the Tevatron is not going to make that happen.

It is possible to run the Tevatron and NOvA together, but NOvA could only get about half the beam intensity planned for it.

That nitpick aside, the point is a good one. The U.S. particle physics program is much more complicated than “Can we keep this particular light switch on?” Projects are inter-connected both through funding constraints and technical constraints, and there are broader political and lobbying implications for program planning decisions of this sort. Fermilab in particular has been enacting over the past several years a clear strategy of migrating toward a long-term, fixed-target program, as the LHC takes the lead on the energy frontier. Numerous experiments are now running, under construction, or under design, keeping the future of the lab viable. Continuing the Tevatron would have direct funding, technical, and personnel interference on this program, and it would have indirect “political relations” implications. (A schizophrenic program is a harder sell than a clearly prioritized one.)

There is also the issue of what the Tevatron could accomplish with an additional two years of running. There are a few corner cases where the Tevatron can do better – for a while – but the LHC will make most of the searches obsolete fairly rapidly. The most likely outcome (IMHO) would have been some number of tantalizing but ultimately unconvincing results that would sit on the shelf until the LHC confirmed or refuted them (if it hadn’t already). This is not a slight on the Tevatron experiments in the least. On the contrary, it is a statement that the experiments have been pushed near their limits, and folks are trying to go just a bit further. I have no doubt they could get at least part way to where they say they could perhaps get. It is typical of the end-stage of a multi-purpose particle physics machine to operate in this mode, and it is natural to try for this last leap. But, when a shiny new LHC with shiny new detectors are ready to go, it is not unreasonable to say, “It’s time to move on.”

To shut the Tevatron down as scheduled is to pull the metaphorical band-aid off. The decision has already had the positive effect of re-focusing the laboratory and the funding agencies toward the future, before the future catches up with an unprepared present.

Looking toward that future, the lab has plenty of projects in the works beyond those already getting started. Mid- to long-term, a major plan is to construct a brand new accelerator – a “proton driver” – that can feed a facility full of fixed-target experiments and secondary beamlines (like neutrino sources). These new experiments, in a very real sense, complement and extend the physics program possible with a collider (the LHC) alone. And, this major undertaking categorically requires a future-looking, focused laboratory.

To add: the most recent similary large machine to be shut down, LEP, went through a similar last-gasp phase, complete with hints of a Higgs boson signal. CERN made the decision to end the LEP program as scheduled so that the laboratory could begin preparing for the LHC.

I have to admit that my understanding of the current state of particle physics is largely limited to the old man gasping about the God particle in Angels & Demons.

Does any of this research have practical applications?

Of course. We just have no idea yet what any of those practical applications are.

If it were just a matter of coming up with the funding, it’d be a no-brainer. Does it really only cost 35 million dollars a year? That’s an incredible bargain, even if it is only the second-best particle accelerator in the world. It sounds, though, like there’s a competing experiment that would use the same tunnels etc., and which can’t really fully coexist with the Tevatron. In that case, it’s just a question of which one is expected to give more results, and that’s almost certainly the new experiment.