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Higgs mass

Okay, let me get this straight: if the Standard Model Higgs is only renormalizable for a particular choice of the Higgs' mass, this is not considered a prediction but a flaw of the model. However, if bosonic strings can only be made consistent in 26 dimensions, or superstrings in 11 dimensions and with the help of supersymmetry these thing for which there is zero empirical evidence are considered predictions of string theory and not flaws. Moreover, were a supersymmetric particle discovered, this would be considered evidence of string theory even though supersymmetry doesn't require string theory. You said it right, though:

the exact Higgs mass ... should be a free parameter in the standard model, otherwise we could stop searching in a range, and it is used by about every theorist who wants to endorse Susy, so it should be a real effect.
Since you're an experimentalist I hope you won't take the above personally, but anyway I'll offer you a bet that the Higgs will be found at 116 GeV.
Unless the Higgs has pretty much exactly 116 GeV, so called loop corrections will destroy the model once more, if there are not more particles to shield these effect.

Dark Energy

As for Dark energy, I'm going to go with the Cosmological constant until there is any evidence to the contrary. As far as I know, even "exotic matter" can't produce a "negative pressure" stress-energy tensor.

Neutrino Mass

I don't consider throwing in a one (or several) right-handed neutrinos and a KCB mixing matrix a challenge to the Standard Model. "Explaining" the masses of the various particles is a challenge, but as far as I can tell there's no candidate for a theory that does that. [No, String Theory is not it: apart from having a proliferation of vacua, the only way they can get a low-energy spectrum of particles is by assuming they all have zero mass, nobody has a mechanism for supersymmetry breaking and the supersymmetry breaking scale just introduces a whole bunch of new parameters to explain.]

Dark Matter

My guess is as good as any other - but if dark matter only interacts gravitationally it won't be seen at the LHC. Actually, the quantum numbers match a "superheavy right-handed neutrino" too...

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Sun Feb 24th, 2008 at 05:13:22 AM EST
[ Parent ]
I won't bet against you. Indirect experimental evidence has its center value below the LEP limit, which is 114. 116 GeV really looks for the moment to be the best guess even without the renormalization argument.

I don't assume string theory to be a physical theory at all, as they can always shift their parameters in a way, that any (non)observation is explained.
My boss completely dislikes Susy, but we have another prof who is now working since decades to prove it (without success).

It may well be, that the LHC finds only a Higgs (and only after quite a long time of running, when it is so low) and nothing else. I'm not at all sure, there is something else, although there are some less compelling hints. However, Susy and some other models should really be dead, if LHC finds nothing.
I only wanted to give you an overview over the reasons why people are searching at all for other things and not simply sit down and say it is not worth to try, because anyhow nothing else than a complete SM can be expected.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers

by Martin (weiser.mensch(at)googlemail.com) on Sun Feb 24th, 2008 at 08:31:02 AM EST
[ Parent ]
Oh, it is definitely worth a try, I never implied otherwise. In fact, given the accesibility of the energy range and the necessarily ad-hoc nature of the various models of the Higgs sector, it would be unforgivable not to try.

If the SM Higgs is found, with no evidence of physics beyond the SM below 1TeV (including "corrections" due to physics at higher energies), I think it will be safe to say that theoretical high energy physics will have "died of success". There would be no strong case for higher-energy accelerators, leaving aside how difficult it would be to build something to probe the 10TeV range.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Sun Feb 24th, 2008 at 09:44:27 AM EST
[ Parent ]


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