This Week’s Rumor

Posted on April 21, 2011 by woit

A commenter on the previous posting has helpfully given us the abstract of an internal ATLAS note claiming observation of a resonance at 115 GeV. It’s the sort of thing you would expect to see if there were a Higgs at that mass, but the number of events seen is about 30 times more than the standard model would predict. Best guess seems to be that this is either a hoax, or something that will disappear on further analysis. But, since spreading well-sourced rumors is more or less in the mission statement of this blog, I think I’ll promote this to its own posting. Here it is:

Internal Note
Report number ATL-COM-PHYS-2011-415
Title Observation of a γγ resonance at a mass in the vicinity of 115 GeV/c2 at ATLAS and its Higgs interpretation
Author(s) Fang, Y (-) ; Flores Castillo, L R (-) ; Wang, H (-) ; Wu, S L (University of Wisconsin-Madison)
Imprint 21 Apr 2011. – mult. p.
Subject category Detectors and Experimental Techniques
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords Diphoton ; Resonance ; EWEAK ; HIGGS ; SUSY ; EXOTICS ; EGAMMA
Abstract Motivated by the result of the Higgs boson candidates at LEP with a mass of about 115~GeV/c2, the observation given in ATLAS note ATL-COM-PHYS-2010-935 (November 18, 2010) and the publication “Production of isolated Higgs particle at the Large Hadron Collider Physics” (Letters B 683 2010 354-357), we studied the γγ invariant mass distribution over the range of 80 to 150 GeV/c2. With 37.5~pb−1 data from 2010 and 26.0~pb−1 from 2011, we observe a γγ resonance around 115~GeV/c2 with a significance of 4σ. The event rate for this resonance is about thirty times larger than the expectation from Higgs to γγ in the standard model. This channel H→γγ is of great importance because the presence of new heavy particles can enhance strongly both the Higgs production cross section and the decay branching ratio. This large enhancement over the standard model rate implies that the present result is the first definitive observation of physics beyond the standard model. Exciting new physics, including new particles, may be expected to be found in the very near future.

See: http://cdsweb.cern.ch/record/1346326?

Update: Jester is up late with some comments here.

Update: Tommaso is skeptical here.

Update: It should be made clear that, while members of ATLAS work here at Columbia, I have no connection at all to them, and they had nothing to do with this. The source of the abstract posted here anonymously as a comment is completely unknown to me. The question has been raised of whether I should allow this kind of material to be posted to this blog and I think it’s a serious one that I have mixed feelings about. On the one hand, ATLAS has legitimate reasons for keeping this kind of information private, on the other, it’s the kind of information that traditionally has sooner or later circulated outside a collaboration in one form or another. As an example, in my graduate student days back in the early 80s, I remember Carlo Rubbia telling a large group of people at the departmental tea about how his experiment had the top quark “in the bag” (actually, they didn’t…).

I’ve generally taken the point of view that it’s not my job to stop rumors, but rather to put out accurate information about them when available to me. But blogs do raise all sorts of issues, and they’re likely to keep coming up. I’m curious to hear if my readers have any wisdom to share about them.

Update: Via Slashdot, some more comment about this, including disclosure of another vector of information transfer out of ATLAS:

Someone left a copy of the note on the printer in my office building. (I work on CDF at Fermilab, but there are others in the building who work on ATLAS at CERN.) The gist of the article is that they found a bump in the diphoton mass spectrum at a mass of ~115 GeV. If the Higgs exists, it is expected to produce a bump in that spectrum, and 115 GeV is a very probable value for the mass of the Higgs. (Experiments at LEP ruled out masses up to 114 GeV, but a mass as low as possible above that fits best with other measurements.)

Now, the inconsistencies: The bump that they found is ~30 times as large as the Higgs mass peak is expected to be. However, due to field theory that I don’t want to get into here, the Higgs peak in this spectrum could be larger than expected if there exist new, heavy particles that we haven’t discovered yet. The latest published result from CDF sets a limit of about 30 times the expected rate at 115 GeV in the diphoton channel. (Yes, this means that, if you’re optimistic enough, there’s just enough wiggle room to fit a Higgs in there while accommodating both measurements.)

The internal note is very preliminary and uses a crude background estimate; I’ll have to see a more thorough analysis before I make any judgment on it. We shouldn’t have to wait very long; I expect that after this leak, they’ll be working overtime to push out a full published result as soon as possible.

Update: Since I don’t traffic in rumors of dubious source, you’ll have to go here to get the latest rumors from someone younger who knows about this whole Twitter kind of thingy…

Posted in Experimental HEP News, Favorite Old Posts | 88 Comments

This Week’s Hype

Posted on April 18, 2011 by woit

This week’s string theory hype is brought to you by a press release headlined Dark Matter and String Theory? from the Institut Laue-Langevin in Grenoble, and another one from the Vienna University of Technology. These have led to a BBC News report which is getting wide distribution, claiming that Neutrons could test Newton’s gravity and string theory. According to the BBC, this is going to allow a search for:

supersymmetric particles, part of some formulations of string theory that suggest that many extra dimensions exist over tiny length scales, which would require the precision that is only now possible with the team’s approach.

The actual physics here is described in this paper. You’ll need to find an atomic physicist to explain exactly what this is about, but the claim is that the author’s new techniques in resonance spectroscopy can potentially be applied to measuring the gravitational potential at micrometer distance scales. This hasn’t actually been done yet. As for what string theory predicts about how the gravitational potential will deviate from the Newtonian value at these distances, the story is the usual: no predictions at all one way or another. Such violations would be very interesting, but say nothing one way or another about string theory.

Update: The folks at Slashdot have started to get a clue, stripping the nonsense about string theory from this story before posting about it here.

Posted in This Week's Hype | 34 Comments

No WIMPs

Posted on April 13, 2011 by woit

A commenter points to the long-awaited release of a preprint from the XENON100 experiment giving results from a 100-day run last year. This is the most sensitive dark matter experiment that has released data. The result: with an expected background of 1.8 +/- .6 events, they see 3 events (i.e. about what you’d expect if there’s nothing there). For a WIMP mass of 50 GeV, this allows them to exclude certain WIMP cross-sections at the level of 7.0 x 10-45cm2. This pretty conclusively kills off some other claims by dark matter experiments to have seen something, especially the CDMS result from late 2009 (see here).

One motivation for supersymmetry has always been that it can provide a WIMP with the right properties to explain astrophysical dark matter observations. This new data rules out some (if you use the SUSY expectations plotted in the new paper), or most (if you use the expectations plotted in the CDMS paper, see here and here) of the possible parameter space where such a particle is expected, providing yet another nail in the SUSY coffin.

Update: More details available at Resonaances and Tommaso Dorigo’s blog.

Update: For a detailed analysis of the implications of the XENON100 result for supersymmetry models, see here.

Posted in Experimental HEP News | 106 Comments

Short Items

Posted on April 12, 2011 by woit
  • For a while now the situation with this year’s budget for science in the US has been very unclear, with threats being made of huge cuts to be instituted in the middle of the fiscal year, requiring shutdowns of labs, etc. The recently negotiated budget agreement turns out to involve only relatively small cuts for both the NSF and the DOE Office of Science, more here and here. Details still have to be determined and the legislation has to be passed, but it looks like most physics and math research will escape any serious immediate cuts. The new fiscal year starts October 1, and fighting over that budget has not even begun. From the hearings already held, it looks like math and physics research has bipartisan support, but in the new environment of significant budget-cutting, focused on discretionary non-military spending, I’d guess that budget levels for the next few years will be flat at best.
  • There’s an interesting interview with Dennis Overbye of the New York Times here. He’s noticed a problem with string theory:

    One pet peeve is press releases about papers that show that string theory is about to be experimentally tested. When you read the fine print that’s never true. There was a press release that the large hadron collider was going to test string theory. It was kind of embarassing for them.

    Scientists and science journalists just take these shortcuts And I think they become enshrined as truth in the public mind.

    He also has some comments about blogs:

    Science journalism is in a very interesting, very turbulent state I think. We still have newspapers. Some newspapers still have science reporters, like the Times. I feel like the blogs have risen up to become huge force in the coverage of science. I think the readership now is very fragmented. I think a lot of people get their information from blogs, where people can be more casual or more arcane if they want to be. I think even at my newspaper there’s a difference between people who read the science times and the font page. There are a lot of these different layers of coverage going on.

  • In the category of “string theory about to be experimentally tested” nonsense that Overbye refers to, no press releases this week, but we do have a special section of Science News with an array of over-hyped stories about Cosmic Questions, with the one on string theory assuring us that:

    Even then, the LHC will be far from powerful enough to re-create the single, unified force that physicists believe existed for a fraction of a second after the Big Bang — you’d need a collider as big as the universe itself for that. But the LHC might be able to test some of the predictions made by the leading theory that joins gravity and the other forces.

  • In the category of something I just put on my list to try and find time to listen to, there’s a Science Friday program featuring a discussion about Science and Art between Cormac McCarthy, Werner Herzog and Lawrence Krauss.
  • In the category of talks I’d like to hear but can’t, Graeme Segal will be giving the Felix Klein lectures in Bonn next month, on the topic of Three Roles of Quantum Field Theory.

    • Update: Two more

  • According to a new preprint, CDF’s observed suspicious bump that made the New York Times “is a generic feature of low mass string theory”. No word yet on whether there’s going to be a press release. I guess this also means that if D0 doesn’t see the bump, that pretty much rules out low mass string theory since its generic feature is not observed, right?
  • Langlands has written a very interesting review for Mathematical Reviews of Ngo’s paper proving the fundamental lemma.
    • Posted in Uncategorized | 12 Comments

    More on Scattering Amplitudes

    Posted on April 10, 2011 by woit

    Last week was the beginning of a program at the Santa Barbara KITP entitled The Harmony of Scattering Amplitudes which will focus on topics including recent advances in computing N=4 super Yang-Mills scattering amplitudes. Talks are available on-line here. There’s a full schedule of talks in the program and related talks here. On Thursday, Nima Arkani-Hamed will give a talk on “The planar integrand of N=4 super-Yang-Mills theory”, which some wag has scheduled as lasting from 1:30pm to 5am.

    For a survey of some of these recent developments, a correspondent points me to the thesis of Arkani-Hamed’s student Jacob Bourjaily, which has just appeared online here.

    Posted in Uncategorized | 8 Comments

    Suspicious Bump

    Posted on April 6, 2011 by woit

    Last night a new preprint from CDF appeared at the arXiv, discussing a signal observed in their data, at about 3 sigma significance, that could in principle correspond to a new particle not seen or predicted before. This morning’s New York Times has an article about this here. The Times does a pretty good job of getting quotes from relevant experts and explaining the situation, which is basically “if it’s real that’s very exciting, but it probably isn’t”.

    I went to check Tommaso Dorigo’s blog only to find that he had a short posting up explaining that a more detailed one was embargoed until the public talk this afternoon at Fermilab (live stream at 1600 CDT here). This seemed rather odd since the Times had clearly been given the story a few days ago, embargoed only until last midnight. He now has a full posting up, and you should go there for a detailed and authoritative look at what this all means (most likely not much, modeling the huge background you have to subtract is hard).

    Update: For other blog postings about this well worth reading, try Michael Schmitt, Resonaances, Gordon Watts and Flip Tanedo.

    Update: Took about 21 minutes from the time of release of this data to submission of a paper explaining it.

    Posted in Experimental HEP News | 20 Comments

    2011 Templeton Prize

    Posted on April 6, 2011 by woit

    This years $1.6 million dollar Templeton Prize has been awarded to astronomer and cosmologist Sir Martin Rees. The Templeton Foundation has traditionally been largely devoted to promoting the intersection of science and religion, so one surprising aspect of this choice is that, while Rees is a very accomplished scientist, he doesn’t believe in God (although he likes the music and architecture in churches):

    In fact, Rees has no religious beliefs, but considers himself a product of Christian culture and ethics, explaining, “I grew up in the traditions of the Anglican Church and those are ‘the customs of my tribe.’ I’m privileged to be embedded in its wonderful aesthetic and musical traditions and I want to do all I can to preserve and strengthen them.”

    Rees does seem to believe in something that the Templeton people are willing to take as a replacement for belief in God: belief in the Multiverse. He has been one of the leading figures promoting the Multiverse and anthropic explanations, even before the recent string theory landscape pseudo-science made this so popular. For more about his views, see a 2003 interview In the Matrix, which leads off with:

    All these multiverse ideas lead to a remarkable synthesis between cosmology and physics…But they also lead to the extraordinary consequence that we may not be the deepest reality, we may be a simulation. The possibility that we are creations of some supreme, or super-being, blurs the boundary between physics and idealist philosophy, between the natural and the supernatural, and between the relation of mind and multiverse and the possibility that we’re in the matrix rather than the physics itself.

    Something for future Templeton candidates to keep in mind: no need now to believe in a Christian God, belief in “The Matrix” is good enough.

    Posted in Multiverse Mania | 23 Comments

    The Bogdanov Equation

    Posted on April 3, 2011 by woit

    Another book that I picked up in Paris is Lubos Motl’s L’Équation Bogdanov: Le secret de l’origine de l’Univers?. It’s a rather weird document, a mish-mash of defense of the Bogdanovs (partly by comparing their ideas favorably to loop quantum gravity), generalities about cosmology, and promotional material about string theory. Among the odd features of a book entitled “The Bogdanov Equation” is that there is no “Bogdanov Equation” in the book (or anywhere else, as far as I know). In a comment on his blog posting about the book Lubos writes

    If there is an equation written by the twins that can be shown to explain the origin of the Universe, you will read about it in the book. If there is none, you won’t find such big statements. But I can’t tell you and others the punch line here. Wink

    I don’t think it’s hard to guess which alternative is the right one…

    One of the great mysteries of the book is that of its authorship. Supposedly it was written by Lubos in English, then translated into French. I don’t doubt that large parts of it were written by him, although in a style somewhat different from his blog, and then passed through the filter of translation. Some parts of it though, especially some of the details of the endless defense of the Bogdanovs I can’t believe were written by him. For instance, pages 187-189 are taken up with a translation into French of this internet mailing list posting by “Osher Doctorow Ph.D.”, and the author is described as “Professor Osher Doctorow, mathematician at the California State University”, which appears to be misinformation of a Bogdanovian rather than Lubosian sort.

    Another commenter on the same blog posting by Lubos gives a long and detailed list of dubious things in the book and states that “To make it short, I have the impression that you are not the sole author of the book.”, asking him to clarify this issue. The response is

    Sorry but I have neither time, nor desire, not the full rights to answer ten kilobytes of such questions, some of which are well-informed observations but most of which are not.

    The book is created not only as a blog but also to satisfy a contract with the publisher. So I was okaying some proposals from the publisher. It is essentially good if you can identify these places.

    Theoretical physics in recent years has produced some very odd things, this book is one of the most bizarre.

    Posted in Book Reviews | 18 Comments

    Multivers: Mondes Possible de l’Astrophysique, de la Philosophie, et de l’Imaginaire

    Posted on April 3, 2011 by woit

    While I was in Paris recently I picked up several French books that aren’t readily available in the US. One of these is entitled Multivers: Mondes Possible de l’Astrophysique, de la Philosophie, et de l’Imaginaire, and it takes the form of a conversation between theoretical physicists Aurélien Barrau and Jean-Philippe Uzan, as well as historian of science fiction Patrick Gyger and philosopher Max Kistler. Astrophysicist Isabelle Joncour acts as moderator. The conversation is often dominated by the provocative philosophical flights of fancy of physicist Barrau, with philosopher Kistler playing the role of providing sobriety and down-to-earth arguments.

    The contrast with the typical Multiverse Mania books of the Anglo-Saxon world is striking. French intellectuals are seriously educated in philosophy, and think it natural to carry on arguments invoking the ideas of a wide range of philosophers, even in contexts such that similar Americans wouldn’t see the point of raising philosophical issues. In this case, some of the discussion revolves around the ideas of American philosophers David Lewis and Nelson Goodman about “possible worlds”. It’s amusing to note that it would probably be extremely difficult to get together for a discussion a group of American physicists who had even heard of these two of their countrymen, much less be capable of seriously discussing their ideas. Maybe that’s just as well though, as professional philosopher Kistler makes a good case that the “possible worlds” at issue in this sort of philosophy don’t really have anything to do with the multiverse.

    Barrau takes a position refreshingly agnostic about string theory and LQG, deploring the ideological warfare between them. Unlike most physicists though, who were interested in string theory when it might have predicted something and are now losing interest, he claims that the fact that it can’t predict things is what got him to really like string theory:

    la theorie des cordes commence à m’intéresser à partir du moment où, précisément, elle prend ce tournant où l’on ne sait plus très bien où on va et où on change les règles du jeu au milieu de la partie. Ca devient très motivant!

    string theory starts to interest me precisely from the moment where it takes this turn; one doesn’t much know where one is going and one changes the rules in the middle of the game. This starts to become appealing!

    For Barrau, it’s just when string theory starts to turn into pseudo-science that it interests him. In brief, he agrees that the string theory multiverse moves the field from physics into metaphysics, but thinks that’s a good thing. He’s in love with the idea of finally being free from many of the conventional constraints physicists labor under as they try to do science and the possibility of taking up again the overlap of some French philosophy with science that Alan Sokal very successfully made a joke of. He starts out:

    En philosophie francaise, je pense à Deleuze et à son rhizome, au “plus d’un” de Derrida, au(x) toucher(s) chez Nancy, au nominalisme de Foucault, a l’ontologie du multiple de Badiou…

    and immediately realizes that the question of Sokal must be addressed if you’re going to go on like that:

    Je crains que l’on soit encore dans une sorte de timidité généralisée qui est peut-être issue des contrecoups de la triste affaire Sokal. Il est tout à fait souhaitable d’enjoindre les gens a ne pas dire n’importe quoi. Cela ne se discute pas. Mais il serait dommage que cet excès de précaution leur interdise tout simplement de penser à partir des constructions scientifiques. La physique d’aujourdhui me semble fabuleusement propice à philosopher, il faut oser.

    I fear that we’re still in a kind of generalized timidity that may have come about as a consequence of the sad Sokal business. It’s completely desirable to insist that people not say just anything, that’s not up for discussion. But it would be a shame if too much caution keeps them from thinking starting with scientific constructions. Contemporary physics seems to me fabulously propitious for philosophizing. One must be daring.

    There’s much abuse directed towards Popper, falsifiability, and of crude attempts to separate science from non-science. Barrau is very happy with the idea of not having any way of distinguishing the two, while Kistler tries to remind him that, tricky as it may be, there’s an important distinction involved. What seems important to me here is maybe more of a sociological than philosophical point, and it’s a bit like the one that motivated Sokal. If you don’t have any standard at all for what is science and what isn’t, you lose control of the powerful role of science in how we see the world, and put yourself at the mercy of socially stronger forces who will be happy to take on this role and grab control and power away from those who have disarmed themselves. In the specific local area of fundamental physics, if there’s no way to recognize that ideas have failed, those with a vested interest in a set of failed ideas will never give up their control of the discourse. Instead of the philosophers listed by Barrau, someone like Michel Foucault might be more relevant…

    Posted in Book Reviews, Multiverse Mania | 10 Comments

    Back to the Usual

    Posted on April 2, 2011 by woit

    Since April 1 is over, choice of blog topics will revert to the usual, and at some point I’ll get around to reverting the logo. There are plenty of other blogs covering desserts, biking, and what’s wrong with Obama, so I think I better stick to my market niche.

    In Langlands/String Theory/Media news, the last episode of The Big Bang Theory (The Zarnecki Incursion) starts off with a scene where the white-board in the background has a central object in Langlands theory. It’s the representation of the upper-half-plane modulo SL(2,Z) as an adelic double coset, with a picture of a tree for the prime p=2. Next week, my colleague Brian Greene will make a guest appearance. For more Big Bang coverage, see Lubos, who really does seem to think that he’s Sheldon.

    Later today I’ll post the usual tedious new review of a book about the multiverse. But, first I need to get breakfast at Silver Moon, and the weather is great for a bike ride…

    Posted in Uncategorized | 14 Comments