Various and Sundry

Later this week there will be a mini-workshop at City College organized by some of the CUNY particle theorists, on the topic of Yang-Mills Theories: nonperturbative aspects. The schedule of talks is here, I’m planning on attending some of them.

Also this week, Witten is speaking at the IAS on Wednesday with the title “Operator Expansion Product of ‘t Hooft Operators”. I’d like to go down to Princeton to hear this, but have to teach here around the same time, so won’t be able to attend the talk. Maybe someone who does attend will tell us about what Witten had to say.

There’s an interesting new particle theory blog, called Resonaances, and written by someone in the CERN Theory Group (who for now is operating anonymously as “Jester”, also commenting here). It includes reports of talks at the recent Winter School on Strings, Supergravity and Gauge Theories, discussion or recent ideas about supersymmetry breaking using metastable vacua, and scary photos from the Christmas party, which included someone playing a Borat/Theorat character and Wolfgang Lerche as the string pope, intoning the following prayer:

Our Witten, which art in Princeton,
Hallowed be thy name.
Thy Nobel come,
Thy will be done,
In CERN as it is in the US.
Give us this day our daily string,
And forgive us our theory,
As we forgive those who do phenomenology.
Lead us not into experiment,
And deliver us from tests.
For thine is the arXiv,
Hep-th and math-AG,
For ever and ever,
Amen

Over at Tommaso Dorigo’s blog, he’s spreading wild rumors about a Higgs signal seen by CDF. He does acknowledge that this “signal” is not the sort of thing one should take seriously, almost certainly a statistical fluctuation. With the Tevatron getting closer to the point where it might actually see the Higgs, and the LHC sooner or later starting to produce data, I look forward to the prospect of lots of rumors being put out by bloggers of Higgs or SUSY signals. I remember many years ago that there were always new rumors of things being seen at experiments, which just about always turned out to not actually be there. In recent years the large experimental collaborations have done a better job of acting responsibly and not letting wild rumors get out. Maybe the blogging phenomenon can play a useful role in getting the irresponsible rumor game going again. Any CDF/D0 people who want to send me rumors that I can then irresponsibly help propagate are encouraged to do so.

I just got a copy of a new textbook about Lie groups and their representations, called Compact Lie Groups, by Mark Sepanski. I had been frustrated that there wasn’t a book out there of just the right level with the same perspective I’m taking during the next few weeks of my graduate course, but Sepanski looks just right. From what I’ve seen so far of it, I recommend it highly as a place to learn about things like the Peter-Weyl and Borel-Weil theorems.

Another interesting book I recently acquired is Terry Gannon’s Moonshine Beyond the Monster, which is highly readable as well as entertaining, and contains a wealth of information about affine lie algebras, “modular moonshine”, vertex operator algebras and conformal field theory, and much more.

There are two new textbooks now out about string theory and attempts to get the a unified theory of particle physics out of it, by Michael Dine, and by Katrin and Melanie Becker and John Schwarz. I haven’t had a chance to look at either very carefully, but they both seem to neglect to mention that this idea doesn’t work. The thing that most amazes me though is Dine’s choice for one of the three luminaries of the field to get a blurb from that might convince people to buy the book: Lubos Motl.

Update: John Conway, the CDF experimenter whose potential Higgs signal was mentioned here, has joined the Cosmic Variance team, and his first post is one of a series giving the details of this story.

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22 Responses to Various and Sundry

  1. :-) spreading rumors is fun indeed!

    But I will defend strenuously my reputation if put to trial on this one! I just about posted blessed results (shown at conferences) of a reasonable analysis observing a 2-sigma bump _somewhere_ in one spectrum… I am not guilty, your honor!

    Of course, part of the fun in discussing these kind of bumps lies in the fact that usually only those who know better understand that a 2-sigma bump like that has _zero_ significance (because the mass is unknown, and a bump _has_ to happen somewhere).

    All others, who are fascinated by the chance that a higgs is there, of course want to dream on, and I let them do so by presenting some additional suggestion… I claim innocence on this count too, your honor.

    Cheers,
    T.

  2. yagwara says:

    Thanks for the pointer to Terry Gannon’s book.

    On lie groups, do you dislike Brocker and tomDieck for some reason? I ask because I have been wanting to go back and (re)learn some of this stuff and that was one of the books I was planning to use.

  3. Peter Woit says:

    yagwara,

    Brocker, tomDieck is probably my favorite book among the older ones, although unfortunately it doesn’t discuss Borel-Weil theory. The Sepanski book is in some ways similar to Brocker, tomDieck, but simultaneously shorter, covering fewer things that are not so important, and getting to Borel-Weil theory.

  4. kuos says:

    Lot’s of SUSY/String textbooks coming out, each one destined to become a classic. Perhaps a last ditch effort to cash in before LHC makes 20 years of theoretical research obsolete?

  5. wolf says:

    Regarding the Cuny workshop, it seems to be entirely devoted to two spatial dimensions. Maybe with an eye on applications to critical phenomena/statistical mechanics?

  6. Shantanu says:

    Peter did you find anything interesting/controversial at the KITP workshop
    on singularities at : http://online.kitp.ucsb.edu/online/singular_m07/

  7. Peter Woit says:

    wolf,

    I don’t know if there are any applications of 2+1d YM to stat mech. I think the main reason people are interested in 2+1d YM is as a toy model for trying to solve 3+1d YM non-perturbatively. In 1+1d YM is exactly solvable, in 3+1d there’s very little we know how to do analytically. 2+1d is intermediate in difficulty…

    Shantanu,

    My main interest is in particle physics, so I fear the kind of quantum gravity discussions going on at that workshop just aren’t something I’m interested enough to follow closely. The workshop does appear to have both LQG and string theory people participating on an equal footing, so I guess that’s something worth noting.

  8. Thomas Love says:

    Peter, I just noticed this on your side bar:

    Categories
    Not Even Wrong: The Book (24)
    Uncategorized (476)

    That’s a total of 500 posts, a landmark which should be acknowledged. Congratulations!

  9. Congratulations ??? What a lazy bum! I have 670 posts out and I’ve been around for a third of the time…

    Of course… Hehm… My posts are not quite as interesting, and… Hhruumph… They get a hundredth of the traffic…. And hmmm… I do not have a tenth of the comments to answer. Oh well.
    Congratulations, Peter!

    T.

  10. Who says:

    Yes! Congratulations on reaching the 500 mark, Peter, with a blog that clearly makes a uniquely valuable contribution.
    Also must say I was very glad to see the home-made 2006 topcites. I wouldn’t be surprised to learn that their appearance accelerated Spires and
    prompted them to decide on bringing out the official list by 31 January, the date Travis mentioned in this post:

    http://www.math.columbia.edu/~woit/wordpress/?p=508#comment-21399

  11. Peter Woit says:

    Thanks T. and T., although you may be slightly premature, I think there might be two posts that are in both categories…

    Just upgraded the blog software to WordPress 2.1. If anyone notices any anomalies, let me know.

  12. z3 says:

    Heads up on Distler and Rothstein’s paper in the upcoming issue of PRL discussing possible LHC tests of string theory, or rather it’s generic assumptions — analyticity, unitarity, and Lorentz invariance — through W boson scattering events.

  13. stevem says:

    As regards the CUNY Yang-Mills workshop, what exactly is the current status of non-perturbative analytical calculations of things like mass gap, string tension and confinement? I had heard/read somewhere that the string tension can be estimated for (2+1) YM and is comparable to values obtained from lattice sims. The talks will probably cover such things. Hopefully, they will appear online as the first one looks especially interesting. Or maybe someone attending will report on them. The emphasis seems to be on (2+1) YM. It still seems unlikely that (3+1) YM for SU(3) can ever be solved exactly. Maybe a string dual can be found to pure qcd, but again this seems unlikely, at least right now. Also, does anyone know if any progress has been made on the YM millennium problem? I presume you would have to prove existance of quantum YM and a mass gap strictly in (3+1) and not in (2+1)?

  14. wolf says:

    z3, those generic assumptions of string theory — analyticity, unitarity, and Lorentz invariance — look vaguely familiar to me. Could it be that I have seen them some place else? Maybe some theory not involving strings?

  15. Peter Orland says:

    Stevem,

    There will be several things discussed at the CCNY meeting.

    Right now, what most people are doing in 2+1 dimensions are new strong-coupling methods. In 2+1 the strong-coupling mass gap is proportional to the coupling squared, and the string tension (determined by working out the vacuum state) is proportional to the coupling to the fourth power. These results were shown by lattice strong-coupling methods (not computer simulations) a long time ago, but some new mathematical methods which are quite interesting have been developed to study them.

    I will also present some work I have been doing for the last few years
    on a weak-coupling method for understanding confinement, which
    works only in 2+1 dimensions. The method used two coupling constants, which are arbitrarily small in units of the UV regulator. The
    gauge theory studied this way is not rotation invariant, but quarks
    are confined and adjoint sources are not (for a finite number of
    colors. There is also an interesting picture of string excitations.

    I think what most people hope to gain from the meeting (at least I do) is an approach to confinement in 3+1 which works for weak bare coupling constant.

    Since Peter W. will be going to some of the talks, perhaps he can give
    his evaluation of the meeting.

  16. z3 says:

    Wolf, these principles are not shared by all theories of QG. So a test of them amounts to a weak test of string theory, in that there’s a very low probability string theory would be falsified thru an observed violation of these requirements, but the lack of any violation also only increase our confidence in string theory by a negligible amount. There is quite a bit of publicity stunt in calling this a test of string theory, but there is some physical motivation in it as well.

  17. John Conway says:

    “Wild rumors” ??

    I gave the talk at the Aspen particle physics conference where we broke the news of the results of our search. I was the one who “let the wild rumor out.”

    We showed what we saw, pure and simple. It’s not anything to get excited about statistically, clearly. People did get excited, though, because this is about the Higgs after all!

    You try to suggest it’s “irresponsible” to show your results honestly in public, and discuss them afterwards in the hallway or blogs or wherever…well, that’s just irresponsible of you. So there.

    And, T., there certainly does not *have* to be a bump somewhere. For us we would only expecet such a thing about 2.5% of the time; we are working on refining that number, as I said at Aspen. It’s tricky, as you know.

    What are results do show is that *if* the Higgs is there, at an enhanced rate at high tan beta, we could nail it at the Tevatron before the LHC (on which I also work) does. Now wouldn’t that be interesting?

  18. Peter Woit says:

    John,

    My comments about Tommaso’s posting were a bit tongue-in-cheek. I do think HEP experimentalists are behaving incredibly responsibly these days, rarely if ever promoting signals of marginal statistical significance. Maybe I’m wrong, but I remember this happening much more often 20-30 years ago. I admit to a bit of nostalgia for this kind of activity, for seeing people get excited by possible signals (even if they almost always have their hopes dashed later). So I think maybe a bit more irresponsibility would be a good idea, and I was trying to encourage any inclinations in that direction that Tommaso might have. The only problem is how to keep it out of the science coverage in the press that goes out to the general public…

  19. Yes, John, the mentions of “rumors” and “irresponsibility” were made with half-joking tone, both above and in my blog.

    As for the significance, I totally agree, it is tricky indeed. My opinion is that the CDF signal would be the typical way a 160 GeV Higgs would show up in a statistically-limited analysis such as ours, but it is just as well the typical bump due to a weird fluke in the data.

    We search the Higgs in tens of different mass distributions, in various final states. We HAVE to have a 2-sigma bump somewhere at some point! Of course, you can shrug your shoulders and claim that you are only concerned with your own analysis, but as long as rumors spread only when signals grow above the (say) 2-sigma mark (or if more vocal people start crying wolf at 1.5-sigma, as in LEP II – hruuumpf), we are giving the world a wrong perception of the data if we do not qualify those 2-sigmas. Not your job, of course, so no criticism is implied to you, but rather on the way we publicize our scientific output.

    And I agree with Peter when he says these days we are a bit over the mark with our “protection” of our own data. We’ve been colleagues for 14 years, and you certainly have a very well informed opinion on how I think of the whole matter… Just think of the superjet affair ;-)

    In any case, congratulations for your intriguing result, John!

    Cheers,
    T.

  20. And, Peter, the problem of discussing results among peers without the matter getting known by newspapers is not solvable.

    During the last four months I have been contacted to comment or explain new results posted in my blog by no less than five journalists from Nature, New Scientist, Physics World, Scientific American, Physics Today… (And as you know I am grateful for your directing traffic to my blog now and then, without which I would be a lesser known blogger).

    These people do look for “leaks” in the blogosphere. They have grown smart!

    That, combined with the tough bylaws of my experiment, totally prevents me from real leaks in my blog. What I can do is to hint at things to come. As I did in the post on John’s signal, where I hinted at the fact we will bless a Z->bb signal in CDF soon, and that a few tens of higgs decays could be there if the MSSM signal were true…

    Cheers,
    T.

  21. Peter Woit says:

    Tommaso,

    One solution of course is that if you can’t leak on your blog, you could write me, and I could then spread rumors from my blog… If journalists called me I would deny everything, claim I just made it up.

    A major problem with this whole blogging thing is that some of the best rumors I hear from friends and colleagues I just can’t use, mainly because it would be too obvious where they came from, and the people involved would get annoyed and never tell me anything again. My hopes to become a leading physics/math gossip columnist are unfortunately difficult to realize.

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