The Horror of the Higgs

> “We hates it, we hates it, we hates it for ever!” -_Gollum, from the Hobbit_

Don’t get me wrong. The Higgs is an absolutely wonderful mechanism, and I’ve very optimistic that the last particle of the standard model — the Higgs Boson — will be found over the next few years, either at the Large Hadron Collider or, if experimenters get _very_ lucky, at Fermilab!

As far as particle physics goes, the Higgs would be unlike any other fundamental particle we know of. While all the other particles have a _spin_, or an intrinsic angular momentum, the Higgs is predicted to be spin-0, or spinless.

While all the other bosons in the Universe — the photon, the gluons, and the W’s and Z — are vector particles, the Higgs is predicted to be a fundamental _scalar_, the only one of its kind.

And finally, as far as we know, the Higgs has unique coupling properties; something no other particle has. The Higgs must couple to all of the quarks, the heavy leptons (but maybe not the neutrinos), and the W’s and Z, but _not_ the photon or the gluons.

Why’s that? Because the Higgs is incredibly useful — indeed, it seems to be the only reasonable explanation — for _where mass comes from_. (And if you’re a technicolor enthusiast, please read about flavor changing neutral currents before posting in the comments.)

And realistically, this is what we love the Higgs mechanism for.

The Higgs explains the existence of mass better than any other theory we have, and it would be very surprising if the Higgs Boson didn’t show up at the LHC.

But you might be compelled to ask the following, “**Why** does the Higgs give the values of mass it gives to the 13-to-16 (depending on whether it gives neutrinos mass) particles in the standard model with mass?”

And in my opinion, that’s the real horror of it all. The mass of the electron, the masses of the up and down quarks (that make up the proton and neutron), the masslessness of the photon and gluons, and even the mass of the Higgs itself _are not predicted_ by the standard model!

In fact, if you look at the best predictions we have for the mass of the Higgs, we know that it isn’t quite there!

Now, there might be interesting physics beyond the Standard Model, but realistically, we’d have to be very fortunate to have experimental access to that physics.

The great nightmare of people interested in particle physics is that the standard model works _too_ well. That the Higgs exists somewhere between 120 and 140 GeV, that there’s no supersymmetry or extra dimensions or composite Higgs or technicolor or _anything_ surprising.

And this would mean that we’d never understand _why_ the Higgs couples the way it does, or _why_ the particles in the Universe have the masses that they do; the best we’d be able to say is, “They just do.”

So I’m hopeful that they don’t find _only_ the Higgs, because if they do, we could be living through the last hurrah of particle physics, and there’s too much that we still need to know! Here’s hoping…

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URL: http://scienceblogs.com/startswithabang/2010/11/the_horror_of_the_higgs.php

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