Thursday, June 30, 2016

We need some new ideas

Sabine Hossenfelder writes
At the end of the LHC’s first run at high energies, both the CMS and ATLAS collaborations reported a particularly interesting “bump” in the diphoton channel. ... a bump of a particular size, width and energy could either indicate a completely new, fundamental, beyond-the-standard-model particle, the first of its kind – or a new standard model feature — or it could simply be statistical noise. Despite the fact that it would be the nightmare of most of my colleagues, I’m hoping the diphoton bump turns out to be nothing more than noise.
Since I entered physics, I’ve seen grand unified models proposed and falsified. I’ve seen loads of dark matter candidates not being found, followed by a ritual parameter adjustment to explain the lack of detection. I’ve seen supersymmetric particles being “predicted” with constantly increasing masses, from some GeV to some 100 GeV to LHC energies of some TeV. And now that it looks like the LHC isn’t going to see any superpartners either, my colleagues in particle physicists are more than willing to once again move the goalposts.

Yep. What she said. SuperSymmetry is a way to get the equations to please not give infinity as an answer, but somehow the predicted particles (one for each of the known particles) just never turn up. SuperCemetery of effort.

Perhaps more dramatically, Adam Frank wants to drag some theorists out of Laputa with a few postulates that used to be pretty standard wisdom: "There is only one universe." (a bas le multiverse!) "Time is real" (not emergent), and "Mathematics is selectively real" (the real world doesn't care how beautifully symmetric your equations are).

Two big complaints about string theory are that there's been no convergence on an actual theory that makes testable predictions within its framework(*), and that it predicts SuperSymmetry--which doesn't seem to exist.

I'll add my complaint that when you have to renormalize to get your sums to shake the infinities out of them, there's something seriously wrong with the paradigm of your calculation. I don't know how to fix it. (**)

And in a related vein, I'm pretty dubious of early Universe inflation: the universe expanded extra fast for a while just after the Big Bang. Why? Ummm.. Well, if it did expand that way then observations match theory, so let's assume it did and try to figure out how. And Dark Energy to make the Universe's expansion accelerate.

We need some new ideas.

(*)The assumptions that make up the framework seemed quite nice, though.

(**) UPDATE: I think what I want is a way of finding a problem dual to the type of things we do now, but that is more tractable even if it is less obvious how it connects to the physics.


bs king said...

I've actually been meaning to ask you about something related to this. I just finished reading "The Trouble With Physics" by Lee Smolin, and I was wondering if you'd read it and how accurate it was.

james said...

It's been a few years, but IIRC the book was pretty accurate insofar as it went after string theory hype. I'm not sure that his favorite field (quantum gravity) is a better place to put effort. He knows more about it than I, of course, but ...