The last particle ever?

Cosmologist and science blogger Ethan Siegel has a fascinating article titled Have we reached the end of Particle Physics? I think this is as important as he thinks it is. Here is the gist of it:

there is a new idea gaining traction in recent years when it comes to making a quantum theory of gravity: asymptotic safety. Without going into any mathematical detail (and with full disclosure that I myself don’t understand it as well as I’d like), you can think of it as a mathematical trick that allows you to incorporate gravitation into your QFT….

There’s a very important reason we care about this: if we understand how to incorporate gravity into our quantum field theories, and we’ve measured the masses of all the standard model particles except one, we can theoretically predict what the mass of that one remaining particle needs to be in order for physics to work properly at all energies!

We can do this because demanding that the Universe be stable constrains that last free parameter — the mass of the Higgs boson — to be one particular value. If the mass turns out to be that value, then that’s indicative that, if asymptotic safety is a valid idea, there are no new particles in the Universe that couple to the Standard Model. In other words, there are no new particles to be found by building colliders in the Universe, all the way up to Planck energies, some 15 orders of magnitude more energetic than those probed by the LHC.

But if we can predict that mass, and the actual mass of the Higgs boson turns out to be anything else, either higher or lower, then that means there must be something new in the Universe in order for physics to be self-consistent. Now, here’s the truly amazing thing: that mass was calculated back in 2009, before the LHC was turned on.

You can read the abstract here and the full article here, but what’s truly amazing is that we’ve now found the Higgs, and we know its mass. Want to see what this paper, nearly 3 years old now, predicted for the mass of the Higgs?

holy crap

Holy. Crap.

So I want you to understand this correctly, because this could be huge. If asymptotic safety is right, and the work done in this paper is right, then an observation of a Higgs Boson with a mass of 126 GeV, with a very small uncertainty (±1 or 2 GeV), would be damning evidence against supersymmetry, extra dimensions, technicolor, or any other theory that incorporates any new particles that could be found by any accelerator that could be built within our Solar System.

Fast-forward to this past July, when the discovery of the Higgs Boson — confirmed to be a single, fundamental scalar particle of spin-0 — was announced. What was its mass, again?

According to the combined ATLAS+CMS data (both major detectors), a Higgs of mass somewhere between 125 and 126 GeV was detected with a (robust) significance of 6-σ, with an uncertainty of around ±1 GeV. In other words, those of you who followed the excitement in July may have witnessed the last fundamental particle physics discovery we will ever make.

Pigliucci and Albert slamming Krauss, Yours Truly slamming Albert and (by implication) Krauss

In yesterday’s post at Philosophy & Theory in Biology, Massimo Pigliucci writes:

I don’t know what’s the matter with physicists these days. It used to be that they were an intellectually sophisticated bunch, with the likes of Einstein and Bohr doing not only brilliant scientific research, but also interested, respectful of, and conversant in other branches of knowledge, particularly philosophy. These days it is much more likely to encounter physicists like Steven Weinberg or Stephen Hawking, who merrily go about dismissing philosophy for the wrong reasons, and quite obviously out of a combination of profound ignorance and hubris (the two often go together, as I’m sure Plato would happily point out). The latest such bore is Lawrence Krauss, of Arizona State University.

I have been ignoring Krauss’ nonsense about philosophy for a while, even though it had occasionally appeared on my Twitter or G+ radars. But the other day I read this interview Krauss just did with The Atlantic, and now I feel obliged to comment, for the little good that it may do….

Krauss’s volume [titled “A Universe from Nothing: Why There is Something Rather Than Nothing”] … has been slammed by David Albert in the New York Times:

“The particular, eternally persisting, elementary physical stuff of the world, according to the standard presentations of relativistic quantum field theories, consists (unsurprisingly) of relativistic quantum fields… they have nothing whatsoever to say on the subject of where those fields came from, or of why the world should have consisted of the particular kinds of fields it does, or of why it should have consisted of fields at all, or of why there should have been a world in the first place. Period. Case closed. End of story.”

Now it’s my turn to slam Albert, though certainly not to defend Krauss.

Good heavens! Do these philosophy-of-science types really still believe in an “eternally persisting, elementary physical stuff of the world”? Relativistic quantum fields are calculational devices. Particle physicists study scattering events. A scattering event is characterized by (i) a set of incoming particles with their energies and momenta and (ii) a set of outgoing particles with their energies and momenta. Relativistic quantum fields are algorithms that allow one to calculate for any given (i) the probability of obtaining any given (ii). They have nothing whatsoever to say on the subject of the elementary physical stuff of the world — whether there is such a thing and if so what it might be. Period. Case closed. End of story.

(For a more realistic counterpoint to Albert’s brand of realism (read: reification of calculational tools) recall this quote by N. David Mermin.)

Responding in kind to Krauss’s armchair psychology, Pigliucci puts forth the hypothesis that the reason physicists such as Weinberg, Hawking and Krauss keep bashing philosophy is because they suffer from an intellectual version of the Oedipus Complex (you know, philosophy was the mother of science and all that… you can work out the details of the inherent sexual frustrations from there).

Pigliucci gives kudos to Ross Andersen, who conducted the interview, for pressing Krauss on several of his non sequiturs…. Andersen…: “certainly philosophers like John Rawls have been immensely influential in fields like political science and public policy. Do you view those as legitimate achievements?” And here Krauss is forced to reveal his anti-intellectualism, and even — if you allow me gentle reader — his intellectual dishonesty: “Well, yeah, I mean, look I was being provocative, as I tend to do every now and then in order to get people’s attention.” Oh really? This from someone who later on in the same interview claims that “if you’re writing for the public, the one thing you can’t do is overstate your claim, because people are going to believe you.” Indeed people are going to believe you, Prof. Krauss, and that’s a shame, at least when you talk about philosophy….

Andersen…: “it sounds like you’re arguing that ‘nothing’ is really a quantum vacuum, and that a quantum vacuum is unstable in such a way as to make the production of matter and space inevitable. But a quantum vacuum has properties. For one, it is subject to the equations of quantum field theory. Why should we think of it as nothing?” Maybe it was just me, but at this point in my mind’s eye I saw Krauss engaging in a more and more frantic exercise of handwaving, retracting and qualifying: “I don’t think I argued that physics has definitively shown how something could come from nothing [so why the book’s title?]; physics has shown how plausible physical mechanisms might cause this to happen. … I don’t really give a damn about what ‘nothing’ means to philosophers; I care about the ‘nothing’ of reality. And if the ‘nothing’ of reality is full of stuff [a nothing full of stuff? Fascinating], then I’ll go with that.”

But, insists Andersen, “when I read the title of your book, I read it as ‘questions about origins are over.’” To which Krauss responds: “Well, if that hook gets you into the book that’s great. But in all seriousness, I never make that claim. … If I’d just titled the book ‘A Marvelous Universe,’ not as many people would have been attracted to it.”

In all seriousness, Prof. Krauss, you ought (moral) to take your own advice and be honest with your readers. Claim what you wish to claim, not what you think is going to sell more copies of your book, essentially playing a bait and switch with your readers, and then bitterly complain when “moronic” philosophers dare to point that out.

Lee Smolin, in his “The Trouble with Physics” laments the loss of a generation for theoretical physics, the first one since the late 19th century to pass without a major theoretical breakthrough that has been empirically verified. Smolin blames this sorry state of affairs on a variety of factors, including the sociology of a discipline where funding and hiring priorities are set by a small number of intellectually inbred practitioners. Ironically, one of Smolin’s culprit is the dearth of interest in and appreciation of philosophy among contemporary physicists. This quote is from Smolin’s book:

“I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today — and even professional scientists — seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historical and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is — in my opinion — the mark of distinction between a mere artisan or specialist and a real seeker after truth.” (Albert Einstein)