Higgs Symposium: A More Careful Summary

My rather hasty, breathless and inconsistent summaries (#1, #2 and #3) of last week’s talks at the excellent Higgs Symposium (held at the University of Edinburgh, as part of the new Higgs Center for Theoretical Physics) clearly had their limitations.  So I thought it might be useful to give a more organized overview, with more careful language appropriate for non-expert readers, of our current knowledge and ignorance concerning the recently discovered Higgs-like particle (which most of us do believe is a Higgs particle of some type, though not necessarily of the simplest, “Standard Model” type.)

I’m therefore writing an article that tries to put the questions about the Higgs-like particle into a sensible order, and then draws upon the talks that were given at the Symposium to provide the current best answers. About half of the article is done, and you’re welcome to read it.  Due to other commitments, I won’t probably get back to finish it until next week.  But “Part 1″ is long enough that it will take some time for most readers to absorb anyway…

4 responses to “Higgs Symposium: A More Careful Summary

  1. I would like to understand the Little Higgs Models. For instance, what is a Top prime? How does a vector like fermion differ from a regular fermion and what is the SU(5)/S(5) symmetry? Is is an SU(5) devided by and SO(5). How does this correct the heirachial problem. Could you do an article on that. I can’t find any Layman’s articles on it. Thanks

    • It’s a complicated and tricky story, which is why I haven’t written about it, and why almost no one else has. If we see any sign of this in the data, I will of course write about it.

      The one thing I will say is that a “vector-like” fermion [the name arises for purely historical reasons -- it is not actually a vector] differs from a “chiral” fermion (which is not `ordinary’! in many senses the vector-like one is more ordinary) in that a chiral fermion typically has to get mass from something like a Higgs field, while a vector-like fermion can have mass on its own, without a Higgs field.

      The SU(5)/SO(5) story is something technical that you would not be familiar with; it is not a division symbol but something more complex which typically is only learned in highly advanced undergraduate or in graduate math/physics. I think to write about it would take a series of about four or five difficult articles…

      • I keep walking up to Group Theory to gawk, then I get interested, then I find out it’s hard work (not like reading Professor’s articles). I’ve learned a lot of physics here without the graduate degrees involved. Thanks, Prof.

        • Yes, I often am compressing six years of study, and sometimes 25 years of experience, into a paragraph. It’s an art form that I am still learning. While these complex issues are often more accessible than they initially appear, some of them are still pretty darn complex and inaccessible without serious study. Others are accessible to non-experts but would still take a few lectures. So I am afraid that not all questions have relatively simple answers… even though, fortunately, many of them do.

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