Witten has contributed an essay to the latest issue of Nature about electroweak symmetry breaking. He describes the main conventional ideas about this, ending with the latest anthropic ones. Here are his comments about those:
“One approach is the anthropic principle, according to which the dark energy and the Higgs particle mass take different values in different parts of the Universe, and we inevitably live in a region in which they are small enough to make life possible. If so, many other properties of the Universe that we usually consider fundamental — such as the mass and charge of the electron — are probably also environmental accidents. Although I hope that this line of thought is not correct, it will inevitably become more popular if experiment shows that electroweak-symmetry breaking is governed by the textbook standard model with a Higgs particle and nothing else.”
He ends with the eminently reasonable summary:
“As yet, none of these theoretical proposals about electroweak-symmetry breaking are entirely satisfying. Hopefully, by the end of this decade, experimental findings at the Tevatron and the LHC will set us on the right track. But the diversity and scope of ideas on electroweak-symmetry breaking suggests that the solution to this riddle will determine the future direction of particle physics.”
Witten certainly didn’t need me to point out to him the importance of this problem. But maybe the reason he just said that current proposals are not “entirely satisfying” but didn’t offer any speculation about alternatives is that he didn’t want Srednicki and Distler telling him he was an incompetent moron for thinking there might be alternatives.
Too bad the Nature article is online to subscribers only. This
2003 talk by Witten on a similar theme might be useful for comparison.
http://conferences.fnal.gov/lp2003/program/papers/witten.pdf
The title is “Supersymmetry and Other Scenarios”. The talk
was given at a conference at Fermilab and there was some discussion afterwards, which is included at the end.
Unfortunetely the link is for Nature subscribers only and I don’t have a subscription. However, I distinctively recall that somebody else recently emphasized that EW symmetry breaking may be the key problem. So it looks like Witten is following Woit’s suggestion. One may wonder if the connection is causal or merely temporal. 🙂