Yang-Mills and Wikipedia

Posted on February 26, 2009 by woit

I was recently looking up references about the history of Yang-Mills theory in order to write about it here, and one thing I ran into was the Wikipedia entry for Yang-Mills theory. It has three sections, the first two of which are standard material, but I was surprised to notice that the last section is completely unconventional, promoting the ideas of Marco Frasca and referencing two of his papers. It was written by an anonymous “Pra1998”, who I’m guessing is Frasca himself.

I’ve never tried to edit Wikipedia entries before, but I thought it would be a good idea to remove this material, which is not the sort of thing that belongs there. My edit was immediately reversed. I tried again, justifying this in the discussion section, but the material is still there. At this point, I give up, lacking time to deal with this and any understanding of what mechanisms are available in Wikipedia to deal with such a situation.

Over the last few years I’ve been finding myself consulting Wikipedia entries more and more, especially ones on mathematics. The quality of the mathematics entries is often shockingly high. In the past if one ran into mention of some mathematical concept one didn’t know about, tracking down a readable account of it was often insanely difficult. Now, one can often just look it up in Wikipedia and find a well-written, concise explanation of just the sort needed. It’s a wonderful and incredibly valuable resource, and I’m mystified about how such a high quality is achieved and maintained. I hope the same mechanism, whatever it is, can work for the Yang-Mills entry.

Posted in Uncategorized | 32 Comments

HEP Budget News

Posted on February 24, 2009 by woit

These are dramatic times for news about the US HEP budget, with the FY2009, FY 2010 budgets and stimulus package all coming together at the same time. The final stimulus package was very favorable for DOE and NSF, providing an extra $1.6 billion for DOE science and $3 billion for NSF.

Today there’s a draft FY2009 budget out of Congress, news about it here from Adrian Cho at Science magazine. HEP at DOE was down in FY2008, at $721 million (after a $32 million supplemental appropriation). For FY2009, which is half over, the draft budget has $796 million. There should be stimulus package funding on top of that. A proposed FY2010 HEP budget is being presented to OMB this week, and the President’s FY2010 budget proposal to Congress should be released in April. In the same draft, NSF research will get an overall increase of $362 million to a total of $5.18 billion (see here).

Today HEPAP is meeting in Washington, with presentations starting to appear online here. There are no decisions yet about what the supplemental funds will be used for, but according to the slides the guiding principles are to accelerate ongoing construction projects and update labs, increase operations and support of experiments at user facilities like Fermilab, and fund “selected research programs”, minimizing commitments in out-years. A program to support graduate students and early career scientists is under discussion.

More from HEPAP and more details about the FY2009 budget should be available soon.

Update: An outline of the FY2010 budget proposal from the President is now available. The proposed NSF budget is $7.045 billion, an 8.5% increase from the recent FY2009 omnibus legislation. The $3 billion from the stimulus package is on top of this. No detailed numbers, but priorities listed include “substantial increases for NSF’s prestigious Graduate research Fellowship and Faculty Early Career Development programs.” and increased “support for promising, but exploratory and high-risk research proposals that could fundamentally alter our understanding of nature, revolutionize fields of science, and lead to radically new technologies.” Sounds kind of like FQXI….

Posted in Uncategorized | 1 Comment

On History

Posted on February 24, 2009 by woit

When learning about various ideas in mathematics and physics, I’m always fascinated by the history of these ideas and eagerly read whatever I can find on the subject. Partly this is because my understanding of ideas is often enlightened by finding out where they came from, especially what problems they were invented to solve. It’s also true that the history of these fields is a huge and remarkable story, in many ways far more intricate, subtle and surprising than any novel ever written, and can be appreciated as such. It’s quite possible that I’ve spent more time on this than is healthy, since there are good reasons for the fact that many scientists wait until late in their career to develop serious historical interests. Time spent studying history is not time spent developing new ideas.

One peculiar aspect of the present state of particle theory is that our current best fundamental physical theory, the Standard Model, is getting so old that fewer and fewer active physicists have any first-hand knowledge of its history. To a large degree, this history spans just about exactly a quarter-century, from renormalized QED in 1948 to asymptotic freedom in 1973. Before 1948 all we had were first-order calculations in QED, by 1973 the full Standard Model was in place. Physicists who finished a Ph.D in 1973 are now in their early 60s and soon will be getting to retirement age. First-hand understanding of where the Standard Model came from is now not part of the background of particle physicists in the most active stage of their careers.

One reason I started thinking about this is a recent exchange in the comment section of the last posting, sparked by my referring parenthetically to the fact that Yang and Mills had developed Yang-Mills theory (in 1954) in the context of trying to describe the strong interactions. The SU(2) gauge theory they wrote down didn’t work for this purpose, since what was needed was an SU(3) theory of quark colors, something that had to await at least the discovery of quarks. The SU(2) gauge theory of isotopic spin they were considering ultimately did find a role in the electroweak part of the Standard model, but this idea got started only after the symmetry properties of the weak interactions became clear later in the 1950s. Schwinger and his student Glashow were among the first to work on this idea, with the correct theory not appearing until 1967 after the role of the Higgs mechanism was understood.

Anonymous commenter “H-I-G-G-S” reacted to my allusion to this history as follows:

You said “Actually, Yang-Mills theory was invented to describe part of the standard model (the strong interactions)”

Not true. Go back and read the original paper.

Well, I have read the original paper, as well as a lot of secondary literature about it. The paper begins with a discussion of the symmetry properties of the strong interactions of nucleons and pions, which was the main topic of the day in 1954, due to the large number of strongly interacting states being discovered at accelerators. Nothing about the weak interactions, which was a different topic, with the symmetry properties of such interactions not understood until a few years later.

I devoted a few minutes to Googling “Yang-Mills” and “history”, and turned up quotes from David Gross and Steven Weinberg explicitly stating that the strong interactions were the motivation for Yang and Mills and posted comments with those. It seems though that “H-I-G-G-S” is not satisfied with this, recently responding:

Perhaps Yang and Mills were hoping to develop a theory of the strong interactions. Perhaps not. Where is the evidence that they were? You don’t cite any statements from their actual paper. You don’t direct me to any historical documents where they were interviewed about their thoughts. If you did I would be happy to have a look and I might be convinced that this was indeed their motivation. Instead you argue by appeal to a higher authority, in this case Gross and Weinberg. Of course when they argue about the importance of string theory you do not agree with them, but when they support a point you like they are suddenly experts who cannot be disputed. Gross was 13 years old when the Yang-Mills paper was published. Why do you think he should know what they were thinking?

I had actually cited a relevant statement from the paper, but I’m not sure what if anything could possibly satisfy “H-I-G-G-S”. Perhaps there is a published interview where Yang makes the kind of explicit, unambiguous statement about his motivations that “H-I-G-G-S” requires and maybe someone with enough interest can dig this up. Since “H-I-G-G-S” insists on anonymity, all I know is that he or she is from a major metropolitan area home to major universities, and appears to be a particle theorist who has been around for a while, although not long enough to know much history. Despite this, he/she has rather definite ideas about what this history is, coupled with a steadfast skepticism about any information which might indicate these ideas don’t correspond to historical reality.

I don’t know to what extent the case of “H-I-G-G-S” reflects the general understanding of the historical roots of the Standard Model among active theorists working on trying to extend it. Much effort on this blog has been devoted to trying to puncture the historical narrative that has solidified over the last 25 years about the supposed march forward of such speculative ideas such as extra dimensions, supersymmetry and string theory. Perhaps it would also be a good idea to worry about misconceptions concerning the history of successful parts of the subject, as well as the unwillingness of many particle theorists to give up such misconceptions.

Update: Here are some suggestions for reading about the history of the Standard Model, ordered very roughly from more popular to more technical:

  • The Hunting of the Quark, Michael Riordan
  • The Second Creation, Robert Crease and Charles Mann
  • Inward Bound, Abraham Pais
  • 50 Years of Yang-Mills Theory, edited by ‘t Hooft
  • Pions to Quarks: History of Particle Physics in the 1950s, edited by Brown, Dresden and Hoddeson
  • The Rise of the Standard Model: Particle Physics in the 1960s and 1970s, edited by Hoddeson, Brown, Riordan and Dresden
  • History of Original Ideas and Basic Discoveries in Particle Physics, edited by Newman and Ypsilantis

    • For the early history of gauge theory, there is

  • The Dawning of Gauge Theory, Lochlainn O’Raifertaigh
    • Posted in Uncategorized | 42 Comments

    Mission Accomplished

    Posted on February 18, 2009 by woit

    A few years ago the asset value of string theory in the market-place of ideas started to take a tumble due to the increasingly obvious failure of the idea of unifying physics with a 10/11 dimensional string/M-theory. Since then a few string theorists and their supporters have decided to fight back with an effort to regain market-share by misleading the public about what has happened. Because the nature of this failure is sometimes summarized as “string theory makes no experimental predictions”, the tactic often used is to claim that “string theory DOES make predictions”, while neglecting to explain that this claim has nothing to do with string theory unification.

    A favorite way to do this is to invoke recent attempts to use conjectural string/gauge dualities to provide an approximate calculational method for some strongly coupled quantum systems. There are active on-going research programs to try and see if such calculational methods are useful in the case of heavy-ion collisions and various condensed-matter systems. In the heavy-ion case, we believe we know the underlying theory (QCD), so any contact between such calculations and experiment is a test not of the theory, but of the calculational method. For the condensed matter systems, what is being tested is the combination of the strongly-coupled model and the calculational method. None of this has anything to do with testing the idea that string theory provides a fundamental unified theory.

    The yearly AAAS meeting is the largest gathering where scientists present results to the press and try and draw attention to recent scientific advances. This year’s meeting was held over the past weekend and featured a program Quest for the Perfect Liquid: Connecting Heavy Ions, String Theory, and Cold Atoms. While the presentations were largely a serious attempt to explain this area of research to the public, the fact that this has nothing to do with string theory unification somehow doesn’t seem to have been mentioned, with the result one would expect. The program was reported on under the headline A first: String theory predicts an experimental result, with the story beginning:

    One of the biggest criticisms of string theory is that its predictions can’t be tested experimentally–a requirement for any solid scientific idea.

    That’s not true anymore.

    Another report entitled A prediction from string theory? at Physics World starts off:

    Skeptics find much to complain about in string theory, but perhaps their most stinging criticism has been its inability to be falsified by experiment. A few years ago, one string theorist even told me that a particle accelerator big enough to “see” a string would be so large that its opposite ends would be causally disconnected. So this is not a problem we’ll be solving any time soon.

    Yet even if we’ll never see a string in the lab, it turns out that string theory does make a few predictions about how matter should behave at the quantum level…

    The dramatic news that claims that string theory can’t be tested have been refuted was then spread widely by Digg, so much so that the Symmetry Magazine site featuring the story crashed. The discussion on Digg showed what got through to the public from the efforts of the scientists involved:

    Without a testable hypothesis it was only a String MODEL. Now we truly have a String Theory.

    Michio Kaku just had an orgasm.

    Brian Greene’s next book will be titled “Told You So Bitches!”

    The one string theorist involved in all this was Clifford Johnson, who gives a minute-by-minute description of his participation here. It ends by invoking the phrase made famous by the last US president:

    Mission accomplished. (Hurrah!)

    Update: There a better story on this at Ars Technica, which avoids the misleading “test of string theory” claim.

    Update: Another story about this is Experimenting With String Theory?, where the author for some reason also missed the fact that this has nothing to do with unification, writing:

    So there you have it: finally, a potential concrete way to experiment with the predictions of string theory. But I’ll let the expert say that:

    “This is the first time string theory can help experiments,” Johnson said. “We haven’t proven string theory, but have found a place where string theory has been a modest guide and making testable predictions.”

    Another string theorist has a long blog entry about this here, where the punch-line is:

    And it is just manifestly wrong to say that the lab tests of the predictions of AdS/QCD or AdS/CMT have nothing to do with string theory’s being the unifying theory of gravity and other forces and matter, or a theory of everything, if you wish. They have everything to do with it.

    Update: Chad Orzel has sensible things to say about this here, in the context of a more general debate about the role of science journalists. In the comment section Moshe Rozali’s comment I suspect reflects the feelings of most string theorists about this:

    As for the specifics of your example, I would comment on it, but I decided to go and extract my own wisdom tooth instead. I think that would be much more fun.

    Posted in This Week's Hype | 82 Comments

    Too Many Topics

    Posted on February 15, 2009 by woit

    Last Friday at the KITP there was a celebration of Stanley Mandelstam’s 80th birthday, with talks available here, and some messages from other physicists here. Geoffrey Chew recalls how Berkeley hired Mandelstam away from Columbia, where no one was very interested in what he was doing, in 1958. The next year the same thing happened with Steven Weinberg…

    Recently I’ve noticed two books on a narrow topic not of general interest, but perhaps of interest to readers of this blog: histories of US math departments. They are:

  • Recountings: Conversations with MIT Mathematicians, about MIT.
  • Mathematics at Berkeley, about Berkeley.

    • Perhaps of even more esoteric interest, later this year Princeton University Press will publish Mathematicians: An outer view of the inner world, a book of photographs of mathematicians by Mariana Cook. Some of the photographs are available at her web-site here.

    Via Ars Mathematica: Fulton’s Algebraic Curves is available for free online. It’s a good place to start if you’re looking for a challenging introduction to algebraic geometry at the (quite) advanced undergraduate level.

    Some wonderful expository pieces about areas of mathematics:

  • Ben Webster on higher categories and knot homology.
  • Vaughn Jones on operator algebras and TQFT.
  • Cliff Taubes on Seiberg-Witten Floer homology, in a review of the recent book by Kronheimer and Mrowka.

    • The AMS Notices has an article about the current state of every mathematician’s favorite tool: TeX.

    Les Houches this year will have a summer school devoted to lattice gauge theory.

    For the latest on the question of whether the Tevatron will manage to see the Higgs or rule it out, see excellent postings by Tommaso Dorigo here and here. The bottom line is that by the time the LHC has enough data to start saying something about the Higgs, the Tevatron experiments will have over 10fb-1 of data to analyze, which may, if improvements in their analysis work out, give them a two-thirds chance of seeing the Higgs at 2 sigma level over the entire expected mass range, or a 50/50 chance of seeing it at 3 sigma level over a large range, including a small range just above the 114Gev LEP limit. The Tevatron may remain very competitive with the LHC for some signals far longer than people have been expecting. And, at least for the next 18 months, the US stimulus legislation may make Fermilab better funded than CERN for a change…

    I fear I’ve been remiss about not reporting on the IHES Grothendieck conference that I attended a couple days of when I was in Paris last month. Luckily, there’s a new blog here with a report.

    Protests and strikes in France over Sarkozy’s attacks on the French scientific research system continue, see an English language report here. Some people may have misunderstood my previous mention of this. While it’s not a topic I’m well-informed about, Sarkozy’s argument in favor of moving to something supposedly more American, featuring a market-based, no central government regulation ideology has an obvious problem if you’ve been reading the newspapers.

    Update: Video of the IHES Grothendieck talks is available here.

    Posted in Uncategorized | 7 Comments

    The Landscape for Undergraduates

    Posted on February 14, 2009 by woit

    I was in a local Barnes and Noble today, and noticed that there’s a new, second edition out of Barton Zwiebach’s A First Course in String Theory, which is the textbook for MIT’s course 8.251 String Theory for Undergraduates. The new addition includes a 10 page section explaining the details of how to compute numbers of vacua in the landscape based on flux compactifications, and arguing that this provides an explanation of the value of the cosmological constant. Landscape ideology has now made it to the undergraduate level.

    However, this only seems to be the case at MIT. A couple years ago I wrote about undergraduate string theory courses here, noting that there was an increasing trend to offer them, with MIT, Caltech, Stanford and Carnegie-Mellon providing examples. Recently this seems to have turned around, with Caltech, Stanford and Carnegie-Mellon not offering such a course this year. Somehow I don’t thinking adding coverage of the landscape to the textbook is going to encourage physics departments to teach this material to undergraduates.

    Posted in Multiverse Mania | 13 Comments

    Money For Everything

    Posted on February 12, 2009 by woit

    It now appears that the final US stimulus bill will include very large amounts of spending on scientific research. See here for a copy of the conference agreement. It has \$3 billion for the NSF, \$1.6 billion for the DOE office of science, and \$1 billion for NASA. These amounts are to be spent on top of the regular budgets (about \$6 billion for NSF, about \$1.6 billion for DOE office of science, as well as $400 million for ARPA-E, and \$17 billion for NASA). Basically, the government agencies responsible for funding math and physics research are receiving a one-time influx of money, of order half their annual budget, to be spent as quickly as possible. It will be very interesting to see what they do with it…

    Update: More here.

    Posted in Uncategorized | 17 Comments

    Chamonix For You

    Posted on February 6, 2009 by woit

    The 2009 Chamonix workshop on the commissioning of the LHC has just finished, ending with a message from the Director General, and the opening to the public of the web-site with slides from the meeting (bearing the warning “The Chamonix workshop was an open exchange of views and opinions. All the presentations made at the workshop are available here. The views expressed in individual presentations do not necessarily represent those of the CERN management.”)

    Here’s the press release and message from Rolf Heuer:

    Many issues were tackled in Chamonix this week, and important recommendations made. Under a proposal submitted to CERN management, we will have physics data in late 2009, and there is a strong recommendation to run the LHC through the winter and on to autumn 2010 until we have substantial quantities of data for the experiments. With this change to the schedule, our goal for the LHC’s first running period is an integrated luminosity of more than 200 pb-1 operating at 5 TeV per beam, sufficient for the first new physics measurements to be made. This, I believe, is the best possible scenario for the LHC and for particle physics.

    There were discussions in Chamonix between accelerator and detector physicists on several important issues. Agreements were reached whereby teams drawing from both communities will work together on important subjects, such as the detailed analysis of measurements made during testing of magnets on the surface.

    Since the incident, enormous progress has been made in developing techniques to detect any small anomaly. These will be used in order to get a complete picture of the resistance in the splices of all magnets installed in the machine. This will allow improved early warning of any additional suspicious splices during operation. The early warning systems will be in place and fully tested before restarting the LHC.

    Another important topic for the future was the radiation hardness of electronics installed in the service areas and the tunnel. For many years, particle detector electronics have been designed to cope with events such as loss of beam into the detectors. Until now, this has not been necessary for the accelerators, but will become so when the LHC moves to higher beam intensity and luminosity. Again, with detector and accelerator physicists working closely together, the experience gained from the detectors can be applied to the LHC itself.

    As the Bulletin reported on 30 January, opening up a magnet in which an anomalously high electrical resistance was measured made the reason for the anomaly immediately obvious – a splice had not been correctly made. This is one of two such splices that were identified in the five sectors tested, and as a result the magnet containing the second will also be removed from the tunnel for repair. Since resistance tests can only be conducted in cold magnets, three sectors remain to be tested: sector 3-4 where the original incident occurred and the sectors on either side. Within sector 3-4, the 53 magnets that are being replaced in the tunnel will all be tested before cool down, and the sectors either side will be cooled down early enough to intervene if necessary with no impact on the schedule. This leaves around 100 dipole magnets that we’ll not be able to test until September and a correspondingly small chance that we may find further bad splices that will need to be repaired before operation.

    The Chamonix workshop involved a lot of work by many people. Much progress has been made, and the management now has all it needs to make an informed decision next Monday on LHC restart. I’d like to thank all those involved, and I will be writing to you again early next week to let you know our decision.

    Looking at a few of the slides, it seems that the schedule for work this year has slipped, with the current plan that the machine will be cold in August, checkout in September, with powering tests in Sector 34 taking place in parallel with the checkout, which will end the third week of September. Beam commissioning will not be able to start until then, and the assumption has been that it would take two months to commission the beam and begin collisions for physics. If first collisions are not until late November, it’s clear why they want to run over the winter. The main consideration evidently is cost, they will have to come up with 8 Million Euros more for more expensive power.

    This assumes not all sectors are warmed up. Warming them all up to install the quench protection they would like would add another 5 weeks to the schedule.

    Update: CERN has a press release today confirming the new schedule:

    The new schedule foresees first beams in the LHC at the end of September this year, with collisions following in late October. A short technical stop has also been foreseen over the Christmas period. The LHC will then run through to autumn next year, ensuring that the experiments have adequate data to carry out their first new physics analyses and have results to announce in 2010. The new schedule also permits the possible collisions of lead ions in 2010.

    The decision was made to go ahead while installing additional relief valves in the four sectors that have been warmed up, leaving installation in the four remaining sectors for next year.

    Update: There was a talk today at CERN by Lyn Evans on LHC status and future plans. The current plan for upgrading the LHC luminosity involves a “Phase I” in 2013 that would double the luminosity, and an upgrade of the accelerator complex that would be completed in 2017 and allow further luminosity increases.

    Posted in Experimental HEP News | 7 Comments

    What is String Theory?

    Posted on February 3, 2009 by woit

    Yesterday Joe Polchinski gave a lunch-time talk at the KITP on the topic of What is String Theory? No answer to the question, but he provided an outline of three topics being discussed at the current KITP workshop program that have something to do with it.

  • String field theory: he wrote down the Witten open-string action and advertised that as the best candidate for a definition of string theory that could go on a t-shirt. He noted some of the problems with this, especially how to understand closed strings, which are somehow “emergent”, “hidden in the measure” on string field space, which one doesn’t really understand.
  • The Berkovits pure spinor formalism for quantizing the superstring: if you want a consistent theory, you need supersymmetry, and Polchinski explained that the quantization of both supergravity and the superstring are ferociously complicated subjects. He hopes that the Berkovits formalism will provide a more lucid (perturbative) quantization of the superstring, one allowing a proof of finiteness at higher loops. This topic doesn’t really address the “what is string theory?” question, since it is supposed to be equivalent to other ways of quantizing the superstring, and only valid perturbatively.
  • AdS/CFT and integrability: here there’s an answer to the “what is string theory?” question, but it’s in some ways a disappointing one for the idea of a single string theory that unifies everything and goes beyond QFT. If you believe the full gauge/string duality speculative framework, there are lots of string theories, each of which is defined by fiat to be a certain QFT. If this is right, perturbative string theory is just a tool useful in the study of some strongly-coupled QFTs, and non-perturbative string theory isn’t really a subject distinct from QFT. If you want to unify physics starting from thinking about the SM, at short distances you have a weakly-coupled QFT, with no role for string theory. And, in this picture, there are lots of string theories…

    • At the end, someone asked about the LHC and supersymmetry, Polchinski responded that string theory didn’t require LHC-scale supersymmetry, but if supersymmetry was discovered at the LHC then there would be a “sociological” effect encouraging to string theorists. I also noticed recently that Polchinski has a web-page On some criticisms of string theory.

    In his discussion of the pure spinor formalism, he noted that supersymmetry doesn’t seem to “resonate” with mathematicians, but that pure spinors are more something they recognize. This is certainly true, with supersymmetry something frustratingly close to some standard mathematical constructions, but quite different in other ways. Pure spinors occur naturally when one tries to construct spinors geometrically. Projectively, the space of pure spinors is SO(2n)/U(n), a space which has some quite beautiful properties. In the Borel-Weil geometric construction of representations, spinors are holomorphic sections of a line bundle over this space (for details of this, see the chapter on spinors in Loop Groups, the book by Pressley and Segal).

    For the superstring, one is interested in the case of n=5, and a certain sigma model with target space the space of pure spinors. There’s a more general class of sigma models of which this is a special case, and for more about some of the interesting connections of this to other subjects, see the recent KITP talks by Nekrasov and Frenkel. The Frenkel talk is especially interesting, since it involves several other quite beautiful related ideas. He describes one motivation for studying some of these sigma models that comes from geometric Langlands. While he was at Santa Barbara, Frenkel also gave two nice survey talks about geometric Langlands, see here.

    Update: Clifford Johnson explains here that not only do we not know what string theory is, but we can’t even say anything useful about what it isn’t, other than “it is not a theory of strings”. The problem with this situation, according to him is:

    people who don’t know what they’re talking about, and sometimes with an axe to grind, shouting loudly (and sometimes deliberately misleadingly) about it.

    Update: More thoughts from Clifford on the question of how to deal with string theory critics.

    Posted in Uncategorized | 49 Comments

    No Chamonix For You

    Posted on January 30, 2009 by woit

    In the last posting I linked to the web-site for next week’s LHC Performance workshop at Chamonix, where the state of efforts to recover from last September’s accident and plans for this year will be discussed. As in many previous cases, linking to an authoritative information source about what is going on at the LHC had the effect of it being quickly shut off to the public. I guess CERN really is serious about the idea that information about problems at the LHC is now only supposed to come from the DG’s office.

    So, from now on, I’m sorry to have to do this, but I won’t be linking to any such information sources that people point me to or that I run across. Instead, I’ll try to continue to post here authoritative information that comes my way, without indicating its source. Today, I’ll just note that I’ve heard from an authoritative source about the current informed guesses for when the LHC will be able to start doing physics. The current hope is for first usable collisions at 5 TeV (per beam) in October, with two months for a physics run at that energy before winter shutdown. Peak luminosity would be a few times 1031, integrated luminosity a few tens of pb-1.

    Update: CERN does seem to be making an effort to put out more information about the status of the LHC through their press office. Yesterday there was this update posted as “breaking news”, not waiting for the next issue of the weekly bulletin. The news in the update is uniformly good, telling us about how it has been “a good week”. What will be interesting to see in the future is whether less encouraging news makes it out to the public…

    Update: The web-page denying access to the Chamonix slides has been changed, it now reads:

    This site is temporarily password protected during the duration of the LHC workshop but will be re-opened immediately after the workshop.

    I guess that CERN still wants the news of whatever is presented at Chamonix to first come from their press office, but realizes that making available the detailed technical discussion behind this news is a good idea.

    Posted in Experimental HEP News | 21 Comments