Higgs Non-News

Posted on November 18, 2011 by woit

The combination of summer ATLAS and CMS Higgs results has finally appeared today (see here and here). This was originally supposed to be ready back in August, and has been circulating in various versions for quite a while. The bottom line (95% exclusion for 141-476 GeV) was mentioned here last week. They also quote limits using a much more stringent standard (99% exclusion for 146-443 GeV, excepting three small regions). Also worth mentioning is the 90% exclusion result, which reaches down to 132 GeV, leaving a SM Higgs possible only within the region 114-132 GeV.

What everyone really wants to know is when the experiments will release results based on the much larger full 2011 data set. Today’s HCP 2011 talk just says:

LHC experiments will analyze the x3 data already collected before 2012 Winter Conferences.

Tevatron will provide the final results on 10 fb^{-1} by the 2012 Summer Conferencences.

On the same time scale, there will be a combination LHC + Tevatron.

On this schedule, a possible 95% Higgs exclusion would not happen before next summer. However… I’ve seen comments from Fermilab that they should have results ready for Moriond in early March, and they expect to be able to rule out the Higgs at 95% (if it isn’t there), over the relevant mass region. More immediately, the LHC experiments have been tasked to provide updates of their Higgs results, including per/experiment combinations, for the CERN Council Week (December 12-16). Rumors from the two experiments indicate that one experiment is seeing no excesses that could be attributed to the Higgs, the other only a very small number of events in one channel (ZZ->4l). It seems not impossible that the results available (publicly or not…) mid-December will come within striking distance of ruling out the Higgs (at 90% or 95% level) over the relevant low mass range.

One interesting aspect of today’s data release is that it agrees closely with what Philip Gibbs put together back in September. For more about this, see here, especially this plot. In the past, many have speculated that the first observation of the Higgs would be reported on a blog. Now, it’s looking not unlikely that a possible exclusion of the Higgs will be first reported at viXra log…

Update: CMS has released a video including footage of their internal discussions back in August when they decided not to release the ATLAS/CMS combination. There’s no real explanation of what changed, but by November people’s concerns had been addressed and they decided to release the combination.

Posted in Experimental HEP News | 31 Comments

Knots and Quantum Theory

Posted on November 15, 2011 by woit

A commenter on the last posting pointed to the new video available at the IAS site of Witten’s recent public talk there on Knots and Quantum Theory. The talk is aimed at a general audience, including supporters of the IAS, so it’s rather non-technical. For the technical details behind what Witten is talking about (his recent work on Khovanov homology and QFT), see this survey for mathematicians, a survey for physicists at Strings 2011, and this paper.

For me an interesting part of Witten’s talk was how he described the evolution of his ideas about this topic, and the relationship to geometric Langlands. He also had interesting comments about number theory and the Langlands program, denying any real knowledge of the subject, but arguing that sooner or later (probably later, after his career is over), there would be some convergence of number theory Langlands and physics. He finds the coincidence of geometric Langlands showing up in QFT so remarkable as to indicate that there are deep connections there still to be explored. I suspect that he sees the likely path of information going more from physics to math, with QFT ideas giving insight into number theory. While I agree with him about the existence of deep connections, I suspect the influence might go the other way, with the powerful ideas behind the Langlands program in number theory someday providing some clues about QFT useful to physicists.

Also on the Langlands program topic, this semester we’re having a wonderful series of lectures on the topic by Dick Gross. He’s a fantastically gifted lecturer, and this series is pitched at just the right level for me, explicating many of the parts of the subject I’ve been trying to learn in recent years but have found quite confusing. It’s a beautiful, very deep, but rather intricate subject, bringing together a range of remarkable ideas about mathematics. In the end though, the Langlands program is really mostly about new ideas in representation theory, and since I’m convinced that deeper understanding of QFT will require new ideas about how to handle symmetries, which is the same thing as representation theory, perhaps finding connections between the subjects won’t have to await Witten’s retirement.

Posted in Langlands | 26 Comments

Dijkgraaf Next Director of the Institute for Advanced Study

Posted on November 14, 2011 by woit

The IAS in Princeton announced today that Robbert Dijkgraaf will take over from Peter Goddard as director starting next summer.

Like Goddard, Dijkgraaf has devoted much of his career to string theory, more specifically the formal side of the subject, including conformal quantum field theories, topological quantum field theories, and their manifold interesting relationships to mathematical issues. Unlike Goddard, he’s from a later generation, getting his Ph.D. in 1989 and entering theoretical physics after string theory had begun to play a dominant role. His cohort of theorists who entered the subject as Young Turk revolutionaries riding the wave of string theory is now settling into the role of Grand Old Men.

Dijkgraaf is known as a masterful expositor, with pretty much any survey article by him you can find sure to be lucid and very much worth reading. He also has world-class political skills, recently overseeing the review of the IPCC, a topic putting him at the center of the religious war over climate change. His background makes him an ideal choice to lead an institution like the IAS, one with a great history in theoretical physics and mathematics, and an important ongoing role to play in keeping those subjects healthy.

Posted in Uncategorized | 10 Comments

Models.Behaving.Badly

Posted on November 14, 2011 by woit

Emanuel Derman has a fascinating new book out, Models.Behaving.Badly, which I’ve been intending to write about here for a while now. One of the problems that has kept delaying this is that every time I start to write something I notice that a new review of the book is out, and it seems to me quite a bit better than anything I have to say. An example that comes to mind is this review from Cathy O’Neil at mathbabe a while ago, another is a new one out today at Forbes. Any book that attracts so many thoughtful reviews has to be worth reading as well as capturing something important about what is going on in the world.

There is a somewhat frivolous virtue of the book that I haven’t noticed other reviews discussing: the wonderful title. I can’t help but enjoy the double meaning linking two of the out-of-control groups that are features of downtown life here in New York. One might think that drunken fashion models in downtown clubs and quants at financial firms don’t have a lot to do with each other, and yet…

Derman’s first book, My Life as a Quant (which I wrote a little bit about here in the early days of this blog) tells the story of his move from high energy theory into financial modeling. He was one of the first to do this, and that book reflects a time when the financial industry was riding high, with the role of quants and their models relatively uncontroversial. With his new book, he’s also one of the first, this time in his disillusioned but serious look from the inside at where we are today:

I am deeply disillusioned by the West’s response to the recent financial crisis. Though chance doesn’t treat everyone fairly, what makes the intrinsic brutalities of capitalism tolerable is the principle that links risks and return: if you want to have a shot at the up side, you must be willing to suffer the down. In the past few years that principle has been violated.

His focus is on the role that models inspired by physics have played in this debacle, arguing that they have been used in a fundamentally misconceived way, and explaining the evolution of his own understanding:

… I began to believe it was possible to apply the methods of physics successfully to economics and finance, perhaps even to build a grand unified theory of securities.

After twenty years on Wall Street I’m a disbeliever. The similarity of physics and finance lies more in their syntax than their semantics. In physics you’re playing against God, and He doesn’t change His laws very often. In finance you’re playing against God’s creatures, agents who value assets based on their ephemeral opinions. The truth therefore is that there is no grand unified theory of everything in finance. There are only models of specific things.

Much of the book is devoted to explicating his views about the importance of distinguishing between “theories” that are supposed to accurately capture phenomena, and “models”, which are metaphors which which only approximately capture some aspects of phenomena. As examples of theories, he discusses not just QED, the quintessential accurate theory of the physical world, but also Spinoza’s theory of the emotions. Besides the financial models that are the focus of the book, he also covers a wide range of other failed models. The book begins with a short memoir of growing up in South Africa, where he was a member of a Zionist youth organization, and its failed models as well as the racial ones of apartheid played a role in his coming of age.

If you’re part of the modern world which generally finds actual books too long and time-consuming to read, Derman has an often enjoyable blog, and for the truly ADD-afflicted, he also has one of the very few twitter feeds I’ve seen worth following.

Posted in Book Reviews | 12 Comments

Higgs Rumor Roundup

Posted on November 10, 2011 by woit

As far as I’ve been able to tell, there’s still nothing definitive one way or the other about the SM Higgs, as the experiments continue to analyze data from the now-finished 2011 pp run. Starting Monday is the HCP 2011 conference which at one point seemed to be a possible venue for announcement of confirmation of hints from early this summer of a Higgs around 140 GeV or so. Those hints disappeared later in the summer, so conventional wisdom recently has been that not much new will come out next week in Paris. A new blog entry from one of the organizers refers to this disappointment, leading to worries about conference attendance, but adds some dramatic and mysterious news at the end. It seems that some experimental collaboration requested a last-minute slot at the conference to unveil a new result that might be the highlight of the conference. They’re on for 15 minutes on Monday, still not announced which collaboration this is, who the speaker is, or what their title is. This may very well have nothing to do with the Higgs: maybe something else travels faster than the speed of light…

At HCP2011, ATLAS will have new results from the H->ZZ->llnunu channel (already released, see here) and from the H->ZZ->llqq channel. Unfortunately neither of these are relevant to the low mass region where the Higgs is believed to be hiding. I don’t know what CMS has up its sleeve. One other thing that will be released is the combination of ATLAS and CMS summer conference data, which will exclude the Higgs at 95% confidence level from 141-476 GeV (and come very close to this exclusion down to about 135 GeV).

It looks like release of new data in the channels that are sensitive to a low mass Higgs will wait longer, until the experiments have had a chance to do some analysis on the entire 2011 data set. Mid-December has been rumored as a date, and a logical bet would be that the CERN Council week would be the time for this, in particular at the Scientific Policy Committee meeting on December 12-13. Rumors going around about this are that there’s still nothing definitive in the crucial H->gammagamma channel, and that in the H->ZZ->llll “golden channel” (very low background), one experiment is seeing no excess at low mass, the other is seeing an excess. Higher quality, better informed rumors are encouraged…

Nature reports here on the discussion at CERN about what to do in the (wonderfully exciting…) event that the SM Higgs is not seen. The first action they’re taking is semantic: if no Higgs is seen at the 95% confidence level, instead of saying that this “excludes” the Higgs, they will announce that it “disfavours” it. So, the first reaction will not be jumping for joy, but a defensive one about how it might still be there.

Whatever comes out in December, I hear the plan is to wait for the Moriond conference at the beginning of March to release a result combining data from all channels (separately for each experiment). The Tevatron may have a result to release then too. Philip Gibbs will then swing into action for the full combination.

Update: Via Philip Gibbs, this talk includes the information that “The CERN DG has requested updates for December council”. Not clear to me if the plan is to release these publicly, or to try and keep them confidential (which may not be easy…).

Update: The mystery new result is from LHCb, a 3.5 sigma observation of CP violation in an unexpected place. Details here, Jester has analysis here.

Posted in Experimental HEP News | 22 Comments

This Week’s Hype

Posted on November 7, 2011 by woit

A couple people have pointed me to an article at New Scientist that requires another edition of This Week’s Hype. According to Nuclear clock could steal atomic clock’s crown:

Such clocks could shed light on string theory. The frequency of the jumps in a nuclear clock will depend on the strong nuclear force, while the jumps by electrons in atomic clocks depend on a different fundamental force. So together they could reveal if the relative strength of the forces changes, as string theory has it.

The amusing thing about the string theory “prediction” that relative strengths of forces change over time is that many string theorists promote as a “prediction” exactly the opposite: according to this argument, change in these strengths would imply large changes in the vacuum energy, which we don’t see, so a prediction of the landscape is constancy. See for example here.

Posted in This Week's Hype | 4 Comments

Extortion

Posted on November 6, 2011 by woit

An explanation of something that readers of this and other related blogs may have run into recently:

An ex-boyfriend of a close personal friend of mine has been posting here and elsewhere repulsive and delusional material about the two of us. A few weeks ago he wrote to her to demand money, telling her that if she didn’t pay up he would go on a campaign to broadcast information discreditable to me and embarrassing to her. She didn’t pay him and what you may have seen is the result of him making good on his threat.

I’ve never met this person, and his accusations are simply untrue. If you’re owner of a blog where this is posted, please delete this material, although it might be a good idea to save a copy in case it becomes evidence in a criminal case. Otherwise please just ignore it completely, unless you’d like to help me out by contacting the blog owner to tell them what is going on and ask them to delete it. Thanks.

Note added: I appreciate the intention, but please do not post comments or advice about this here on the blog.

Posted in Uncategorized | Comments Off on Extortion

Interview With Sidney Coleman

Posted on November 4, 2011 by woit

Via Steve Hsu, at the AIP Center for History of Physics, there’s a transcript of an interview with Sidney Coleman from 1977. It’s provocative and amusing, like the man himself, as well as informative history. Go and read the whole thing, but here are some excerpts:

But you do enjoy working with students or do you?

No. I hate it. You do it as part of the job. Well, that’s of course false…or maybe more true than false when I say I hate it. Occasionally there’s a student who is a joy to work with. But I certainly would be just as happy if I had no graduate students…

I guess your remark means then that you would like to avoid teaching undergraduate courses or even required graduate courses…

Or even special topics courses. Teaching is unpleasant work. No question about it. It has its rewards. One feels happy about having a job well done. Washing the dishes, waxing the floors (things I also do on a regular basis since I’m a bachelor) have their rewards. I am pleased when I have done a good job waxing the floor and I’ve taken an enormous pile of dirty dishes and reduced them to sparkling clean ones. On the other hand, if I didn’t have to, I would never engage in waxing the floors, although I’m good at it. I’m also good at teaching; I’m considered very good at teaching, both by myself and others. And I’m also terrifically good at washing dishes, in fact. On the other hand, I certainly would never make a bunch of dirty dishes just for the joy of washing them and I would not teach a course just for the joy of teaching a course…

So I guess really you would be happier with the format of an institute of theoretical physics? Rather than a teaching institution like a university?

Well no. That makes it too abstract. Because that means, would you like to have a position at, say, the Institute for Advanced Studies? And then all sorts of other things would enter the picture. Like you’d have to live in Princeton which is truly an awful experience.

I was there as a young bride a long time ago.

Young brides get the worst of it. They’re even worse off than the people who are at the University or the Institute because at least the people at the University or the Institute can fill their days by engaging in their professional interests from the moment they wake up until the moment they go to sleep. But if you don’t have that, there is really nothing. Nothing. It’s a terrible place. Dullest place in the world. No I wouldn’t say that, but certainly the dullest place at which decent science or decent scholarship is done in the world today. The only advantage to Princeton is that it’s close to Princeton Junction.

Personally I’m quite glad that Harvard was wealthy enough to support Coleman, while forcing him to teach, since I benefited quite a bit from his teaching, right around the time of this interview. I had heard before that he didn’t enjoy his time in Princeton. Once at lunch at the IAS, a senior physicist visiting there told me about the advice Coleman had given him when he told him he was going to Princeton for a year. The advice was “Be sure to bring with you everything you need.” The senior physicist then told me that: “I recently realized what Sidney was trying to tell me: there are no women here so I should have brought someone with me…”

Posted in Uncategorized | 27 Comments

This Week’s Hype

Posted on November 3, 2011 by woit

Now that the LHC has turned out to be dud, producing no black holes or extra dimensions, the latest news is that physicists are planning a new machine, “to follow in the footsteps of the Large Hadron Collider”. This one will be based on “A laser powerful enough to tear apart the fabric of space”, able to “rip a hole in spacetime”, and it will do this much more cheaply than the LHC ($1.6 billion).

For details, see for instance here, here and here. The new laser will also explain what dark matter is, and provide new treatments for cancer.

It’s unclear to me who is responsible for the extra-dimensional hype, which appears to be inspired by ADD models that were popular 10 years ago (and that became much less so once the LHC turned on and saw nothing).

Posted in This Week's Hype | 56 Comments

Solvay Update

Posted on November 3, 2011 by woit

With the Solvay Centenary conference now finished for over a week, some information has been posted about it on the Solvay Institute web-site, where you can see a group picture of the attendees on the main page. Lisa Randall’s comment comparing the gender balance to that at the first conference is actually rather restrained, given that the fraction of women (2.9%, 2 out of 69, Randall and Silverstein) is smaller now than back in 1911 (4.1%, 1 out of 24, Skłodowska-Curie). Oddly, only women working in extra dimensions seem to have made the cut.

The schedule of talks is here. Perhaps someday we’ll see proceedings of the conference and learn what was in the talks and discussions. For now, this page has links to some outlines of the rapporteur talks. There were two separate sessions related to quantum computing (here and here), as well as sessions on condensed matter, particle physics, quantum gravity and string theory.

The string theory talks seem to have just been about possible applications to condensed matter and to quantum gravity, rather than about using string theory to get a unified theory. Witten attended, but appears not to have given a talk of any kind.

Posted in Uncategorized | 12 Comments