This Month’s Hype

The September issue of Physics World is out, featuring a 13 page advertising supplement for string theory which is pretty much unadulterated hype. The same issue includes an editorial which takes the point of view that the only problem with string theory is that:

String theorists need to do much more to explain their field’s genuine links to experiment

String theory’s lack of falsifiability is minimized as a problem, and the fact that it “raises several philosophical issues, such as the role of anthropic reasoning” is listed as a point in its favor. As for those who complain that string theory predicts nothing, in particular nothing about what will happen at the LHC, they are told to just shut up:

With CERN’s Large Hadron Collider (LHC) due to switch on next year, now is the wrong time to slam string theory for its lack of predictive power. While not able to prove string theory is right, the discovery of supersymmetric particles at the LHC would give it a major boost…

The fact that string theory doesn’t predict supersymmetry visible at LHC scales is actually acknowledged in the advertising supplement by Kachru and Susskind.

The few quotes from string theory skeptics allowed seem chosen to be those that put string theory in the most favorable possible light (except for Phil Anderson, who is reduced to hostile spluttering by Polchinski’s claims that string theory may explain high Tc superconductivity). This allows the editorialist to conclude:

However, the richness of string theory that has become apparent in the last decade, and its increasing contact with the real world, gives theorists something to shout about. This is why our main feature on the subject, which started with fairly modest intentions, has ballooned into the longest ever to appear in Physics World. As the views of even many non-string theorists in the article make clear, the theory still holds all the potential it ever did to revolutionize our understanding of the universe.

The critique of string theory by Smolin and myself is pretty much completely ignored or dismissed, with Susskind quoted as having come up with a new insulting term for us (to him we’re “Smoit”, evidently he likes that better than the “Swolin” favored by those in Santa Barbara). The claim is made that

few string theorists think that the sometimes negative portrayal of string theory in the popular arena recently has had much of an effect other than to irritate people.

Amidst the endless misleading hype contained in the Physics World piece, there’s some that simply is demonstrably completely untrue. The most egregious example might be the discussion of Witten’s Fields Medal which claims that it was awarded him due to his work on string theory compactification spaces:

.. with the study of 6D “Calabi–Yau” spaces making Witten in 1990 the first physicist to be awarded the prestigious Fields Medal

The quotes from Witten himself don’t include any of the hype about connections to experiment. He describes string theory as something very poorly understood, with even the fundamental equations of the theory unknown, and no good ideas about how to find them, leading to the danger that even if his vision is correct, realizing it may just be too hard:

It’s incredibly rich and mostly buried underground. People just know bits and pieces at the surface or that they’ve found by a little bit of digging, even though this so far amounts to an enormous body of knowledge… There is an incredible amount that is understood, an unfathomable number of details. I can’t think of any simple way of summarizing this that will help your readers. But despite that, what’s understood is a tiny, tiny amount of the full picture.. One of the greatest worries we face is that the theory may turn out to be too difficult to understand… [about the search for equations for string theory] This is certainly a question that interests me… but if I don’t work on it all the time, it’s because it’s difficult to know how to make progress.

Unlike Witten, many of the other string theorists quoted seem to have no problem with issuing streams of highly misleading hype claiming “predictions” of string theory. For instance, from David Gross:

String theory is full of qualitative predictions, such as the production of black holes at the LHC or cosmic strings in the sky, and this level of prediction is perfectly acceptable in almost every other field of science,” he says. “It’s only in particle physics that a theory can be thrown out if the 10th decimal place of a prediction doesn’t agree with experiment.

I don’t know how to characterize this kind of claim that string theory is as predictive as other scientific theories, just not able to get accuracy to 10 decimal places, as anything other than out-and-out dishonesty. If someone could come up with a legitimate, distinctive, testable prediction of string theory that gave even the correct order of magnitude for some experimental result, that would be a huge breakthrough.

Michael Green, while describing the landscape and its potential to allow for a small CC as “an enormous success” for string theory, is one of several string theorists characterizing the status of string theory as being just as good as that of QFT, with the landscape not a real problem at all, just a “supposed” one:

This supposed problem with a theory having many solutions has never been a problem before in science.

Several people promote the anthropic point of view, with Susskind describing it as the third superstring revolution, one that is even more of a revolution than the others. Polchinski adds

In terms of changing the way we think about the world, the anthropic landscape is certainly as big as the other revolutions

while Susskind’s colleague Shamit Kachru is described as “in the middle”, sensibly pointing out that it would have been a stupid thing for people to do, once they realized that the ratios of sizes of planetary orbits were environmental, to start claiming that “there is a deep anthropic lesson to be learned from Newtonian gravity.”

All in all, I think that the picture the Physics World article presents of the reaction of leading string theorists to the failure of the superstring unification project is a depressing one. Instead of acknowledging in any way this failure and considering what can be learned from it, on the whole they seem to prefer to abandon science for anthropic pseudo-science, to spout misleading claims of bogus “predictions” of string theory, and make indefensible claims that the lack of predictivity of string theory is not unusual for a science.

On the other hand, among string theory skeptics, I fear that the attitude of Howard Georgi is all too common:

I have been critical in the past of some of the rhetoric used by string-theory enthusiasts,” says Howard Georgi of Harvard University, who coinvented the supersymmetric extension of the Standard Model in 1981. “But I think that this problem has largely corrected itself as string theorists learned how complicated string theory really is. I am concerned about the focus of young theorists on mathematical details, rather than what I would consider the real-world physics of scattering experiments, but with any luck the LHC will take care of that by reminding people how interesting the real world can be.”

The problem with string theory is not too much mathematics and a lack of effort towards making connection to real world experiments, but that it is a wrong idea about unification, and thus cannot ever explain the standard model or predict what lies beyond it. The recent move among string theorists to hype bogus claims about connections to experiment, abandoning the search for greater mathematical insight into string theory as just “too hard”, retooling themselves as more salable “string phenomenologists” and “string cosmologists” is not a healthy trend. It is based on adopting the Susskind-Polchinski “multiverse” revolution in the received wisdom about how to do fundamental physics, slowly turning a once great subject from a science into a pseudo-science.

Update: Lubos is beside himself with glee over the Physics World article, see here and here (don’t miss the photo-shopped “Smoit” graphic of me and Lee Smolin). For something more reasoned, there’s a short piece at Wired.

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134 Responses to This Month’s Hype

  1. Peter Woit says:

    Matthew,

    To be accurate, I did not describe your article as dishonest. Unadulterated hype swallowed whole from experts spouting it, yes. Dishonest, no. The one thing I described as “dishonest” was the quote from David Gross. He’s one of the greats of the field, with tremendous accomplishments to his name, but the quote was not an honest characterization of the situation.

    Actually, I do spend large amounts of my time working on trying to find new mathematical techniques in quantum field theory, which is a form of research into HEP theory. Unlike you, I have a Ph.D. in the subject and have devoted much of my life to its study. But if it makes you feel better to attack me personally and imply that I don’t know what I’m talking about, go right ahead.

    The relation between blogging and journalism is certainly an interesting and complicated topic. Maybe we can discuss it some other time, in a less heated context. Yes you’re right that sometimes this blogging business takes up too much time. It’s our first day of classes here and I should be preparing my course.

    Thanks for sending me a copy of Physics World, I’ll look forward to seeing it.

  2. Bee says:

    ori: as I’ve said over at trf, the comment above is what it is, namely a ‘comment’. It comments on the the statement made, which I found disturbing in its generality, and is addressed to the readers here, including the author of this blog. when I wrote the above, I wasn’t even aware who was quoted, but that doesn’t change that the comment is in my opinion appropriate. if you want to make a complete fool out of yourself, go ahead and tell David Gross that you think I think the message didn’t get across very clearly the way he was quoted.

    besides this, Lubos has changed the ‘moron’ into ‘completely silly’ and I guess his post will undergo further fly-by changes. I honestly don’t have time for that crap – I certainly don’t want to end up in Pilsen or something, so I better go back to work now.

    Best,

    B.

  3. Tony Smith says:

    Peter Woit said to Matthew Chalmers “… Unlike you [Matthew], I [Peter] have a Ph.D. in the subject ..”.

    According to physicsworld.com
    “… Dr Matthew Chalmers is Features Editor of Physics World. He joined the magazine in 2002 after completing an MSc in science communication at Imperial College London. He obtained both his physics degree and

    his PhD in particle physics from Glasgow University,

    after which he spent a year working in quantitative finance in Amsterdam. …”.

    Also, I would like to know Matthew’s personal opinions about the stability of fancy-math finance hedge funds etc in the event that the USA housing market declines and oil prices increase,
    and
    (to stay on-topic) how it might compare with the stability of conventional superstring theory in the event that LHC finds no sign of supersymmetry.

    Tony Smith

  4. Pingback: Stuff you might consider reading « A Quantum Diaries Survivor

  5. jhk says:

    “It is amusing to see a group of people with nearly zero knowledge in high energy physics arguing whether a group of Nobel proze winners is correct or not. Who should I believe ?”

    Which group of Nobel proze winners would that be Ori? Gross and Weinberg, or Glashow and Anderson? Who should I believe?

  6. Dan says:

    Of course string theorists would continue hyping string theory in the event of an LHC null result, but aren’t susy-extentions of the SM, and GUT models also suffer from a lack of predictivity, and is as unable to predict what the LHC will see, in detail, as string theory?

  7. Peter Woit says:

    Tony,

    As I wrote to Matthew, I know nothing about him besides the fact that he’s the author of that article. So, good journalism practice would have indicated that I should have checked before I wrote that he didn’t have a Ph.D. in particle theory. Upon further investigation, it turns out that he does have a Ph.D, but in experimental, not theoretical particle physics.

    And please, don’t even try and carry on a discussion of prospects for hedge funds here…..

  8. Peter Woit says:

    Dan,

    I’ve never been a fan SUSY extensions of the standard model, or GUTs, precisely because they aren’t very predictive. For SUSY, the problem is that don’t know what breaks supersymmetry, and this ruins predictivity. Non-susy GUTs are actually better since they often make more robust predictions. The SU(5) non-supersymmetric GUT was so good on this score that it was falsified (no proton decay at predicted rate).

  9. Eric says:

    Peter,
    Aren’t GUTs and supersymmetric theories only qualitatively predictive at low energies because we lack information about the theories at high energy? Would the standard model not have the same problems without experimental data which is input into the theory? Does the fact that they are unable to predict everything from first principles mean that they aren’t science? In your myopic definition of science this is apparently the case. The point that has been made to you over and over is that string theory is no different than this. The only reason we are currently unable to make detailed predictions from first principles is that we lack knowledge, not because there’s anything fundamentally wrong with the theory. In point of fact, string theory is the right direction and I don’t think anybody who works on it needs to apologize for this.

  10. Peter Woit says:

    Eric,

    No, the problem with supersymmetric theories is not that “we lack information about them at high energies”, it’s that you have to break the supersymmetry. This is not a “high energy” effect. Non-supersymmetric GUTs are often quite predictive, in the SU(5) case so much so that it was falsified.

    “Does the fact that they are unable to predict everything from first principles mean that they aren’t science?”

    No, they’re science because they make a lot of testable predictions that have been confirmed. The problem with string theory is not that it can’t predict everything from first principles, but that it can’t predict anything at all.

    “The only reason we are currently unable to make detailed predictions from first principles is that we lack knowledge, not because there’s anything fundamentally wrong with the theory.”

    The problem with string theory is not that it doesn’t make “detailed predictions”, but that it makes no predictions, none at all. Zip. Nada. Detailed or not detailed. If you work hard on a very speculative idea for more than 20 years ad it doesn’t do what you want, the simplest hypothesis for why is that there is something fundamentally wrong with the idea.

  11. alex says:

    Peter Woit said:
    “I think the great hope of some string theorists is that the LHC will see not only supersymmetry, but a pattern of supersymmetry breaking that corresponds distinctively to a certain kind of string background. Based on this they might then be able to make real testable predictions.”

    Surprisingly, I must say that I fully agree with you on this point Peter. I hope the readers of your blog notice this comment of yours.

    Peter Woit then said:
    “This seems to me to be nothing but wishful thinking, we’ll find out in the next few years.”

    There several indirect hints pointing to TeV scale SUSY so I don’t share your pessimism here.

  12. Eric says:

    Peter,
    The exact way in which supersymmetry is broken is the major part of the information at high energy which we are lacking and this is a big part of the information that will be able to answered once information from LHC/ILC is available. Probably the detailed way in which SUSY is broken will be understood from string theory. Regarding string theory, it will be possible to make detailed predictions once the correct vacuum which describes our universe is found.

  13. alex says:

    Eric, see my comment above.

  14. Bogs Dollocks says:

    After reading the original post and the comments and seeing that theoretical HEP has descended into Ubu pata-phyics I’m soooooooooooooo glad that I left what has become a completely sterile field. There are so many interesting other physics problems to work on.

    The mental gymnastics that people are prepared to perform as to what constitutes a “theory”, a “prediction’ and a “measurement” are truly depressing – I’m completely gobsmacked.

    Hope the LHC find something interesting, otherwise it’s lights out.

  15. LDM says:

    I do think the article does have a bias towards string theory and is more of the usual hype.
    However, every time a string researcher comes out with a new idea, how many science journalists have the background to dig up the relevant paper, read it, and decide if how much is pure speculation and how much is not? This has to be a tough job. But the real problem is the string researchers themselves for putting out the hype to begin with.

    Ori,
    Perhaps you refer to the 1949 Nobel? It is possible to get a Nobel in physics that resulted from an idea that, while brilliant and fruitful theoretically, is later discovered to be wrong.

  16. Arun says:

    Peter,

    Hasn’t there been a shift in the past few years from string theory as “THE theory of everything” to string theory as “a general framework (like QFT or Hamiltonian mechanics) within which a theory of everything may one day eventually be fit”?

    If so, isn’t that an improvement in the state of affairs?

  17. Peter Woit says:

    Arun,

    I don’t see it as an improvment, since it’s just an argument for why string theory research should continue to dominate the subject, despite failing as a theory of everything. The question that has always most concerned me is how one can encourage research into other “general frameworks” than string theory. We know fairly well by now how string theory works as an idea about unification (not at all), so the question is how to find some other framework that is more promising.

  18. Eric says:

    Peter,
    If your potrayal of the current state of string theory research were anywhere near accurate, people would be looking for other frameworks to study quantum gravity in droves. However, this is clearly not the case. The string theory community continues to grow. The simple fact is that the Science World article is an accurate picture of how most scientists view string theory. I would advise that you face up to this and stop deluding yourself.

  19. Arun says:

    Peter,

    Reality legislates what is physical theory, but speculation is a matter of taste. Whether a particular line of speculation is going to be fruitful is a matter of individual judgment.

    What I mean is that if Nobel Laureate X makes a falsifiable claim, any ordinary soul can judge it for oneself (the beauty of science!) but if Nobel Laureate Y says, I have a hunch this is the way to go, then we’ve entered a rarified atmosphere where “which hunches of yours have panned out?” becomes an unanswerable argument.

    Strings may be zero as a theory of physics but dominant as a line of speculative research depending on the interests of the most prominent researchers.

  20. happyday says:

    I honestly don’t have time for that crap – I certainly don’t want to end up in Pilsen or something, so I better go back to work now.

    This thread is extremely interesting (light years beyond the distinctly soft dullness of CV, for instance), but Bee’s post just made my day. I like it so much I can’t help quoting it, even though I have nothing to add.

  21. anonymous hater says:

    Woit,

    I object to your entire approach. In this post there’s no physics, no math, just abstract meta-objections. It’s facile and glib to say that there is no way to concretely debunk a theory that makes no testable predictions, but it’s also plainly laughable when one is talking about something plainly as rich conceptually (whether or not physically correct) as is string theory. It’s extremely difficult for any individual to speak coherently about the totality of something as large as a unification program like string theory without eliding details and nuance; at this level it is always possible to raise some objections. Science is done incrementally and the rub is always in the details.

    The entirety of your critique seems to involve quoting various authorities, pro and con, and analyzing the sociology behind their pronouncements. Let’s remember that despite being a celebrated asshole, Wigner was as good a physicist as there has been.

  22. Shantanu says:

    Eric, I also know of some people who long before Peter wrote his book/had a blog gave up string theory ,because it had no connections to real world and moved to grav. waves or LQG or astrophysics.

  23. Josh says:

    Peter, I used to be a reader of your blog. But I have carefully compared Chalmers’ thirteen-page work stuffed with interesting physics with your rants and you just seem to be a gigantic loser. It seems that Leonard Susskind is right when he says that you failed as a physicist and now you try to revenge to the world. 2 minutes and 40 seconds from the beginning of http://www.kqed.org/.stream/anon/radio/forum/2006/07/2006-07-31b-forum.mp3

    My advise is to shut this website down. Bye, Josh

  24. Chris Oakley says:

    Josh,

    Susskind may well have his wires crossed here. Insofar as he has an academic job, it is not true to say that Peter “never made it as a physicist” and he never “became a [professional] programmer”. Someone suggested on this blog that he was in fact referring to myself, in which case it would be a bit like saying that LS “never made it as a plumber” as my leaving HEP had little to do with my abilities & everything to do with my choice of research topic.

    But I wonder … LS now asks us to gleefully accept the possibility that creating scientific theories is just a matter of finding the right point or points in the Anthropic Landscape, and, by implication, stronger and more deductive frameworks are not worthy of sponsorship. Look up the definition of “physics” in the dictionary as ask yourself – who really “never made it as a physicist”?

  25. Peter Woit says:

    Josh,

    I see you’ve been reading Lubos. And after that, you think I’m a gigantic loser?

    For more about the Susskind interview, see:

    http://www.math.columbia.edu/~woit/wordpress/?p=437

    You string theory partisans are really charming…

  26. mathjunkie says:

    Peter and Lee look alike!

  27. hard gluon says:

    Let’s remember that despite being a celebrated asshole, Wigner was as good a physicist as there has been.

    Wigner was an asshole? How come? I had never heard about that before.

  28. Peter Woit says:

    anon,

    Sorry, but writing anonymous comments into blogs referring to people as “assholes” doesn’t say much for your judgment. And whether or not any particular physicist fits that description has nothing at all to do with what I write here about string theory.

    For the record, I often saw Wigner around the when I was a graduate student and he was already a quite elderly emeritus professor. If asked to rank members of the department on an “asshole” scale, my impression is that he wouldn’t even make 50th percentile. Maybe he mellowed in his old age, but you’re the first person I’ve ever heard characterize him this way.

  29. chris says:

    Chris Oakley,

    suskind has more under his belt than those recent antropic speculations. no matter what he does now, he has an established record.
    or would you claim einstein failed as a physicist, because after 1916 he basically screwed everything up (couldn’t come to grips with quantum mechanics, dreamt up crazy unified theories and not much else)?

    good physicists tend to get weird in their old age and suskind is a very good example.

  30. Cee says:

    Bee,

    why did you backdate your post about Lubos?

  31. Bee says:

    because I don’t want him to get more attention than absolutely necessary. I will change the date to today if September goes into the archives.

  32. Chris Oakley says:

    Hi Chris Anonymous,

    AFAIC anyone who invokes the Anthropic Landscape has not made it as a physicist. I am not directing that just at Susskind.

    Maybe I should have phrased it differently. Try “is demonstrating that wisdom does not necessarily come with age.”

  33. Cheeky Bastard says:

    Chris, I think you should show some consideration for poor old guys who never made it as programmers and became professional physicists.

  34. Chris Oakley says:

    What – like Richard Feynman?

  35. sanity says:

    One question that was raised was whether string theory
    requires SUSY GUTs. The answer is no; string theory
    requires neither low energy SUSY nor GUTs; indeed,
    although this is not covered accurately
    in the article, the Bousso-Polchinski
    mechanism and several frameworks for moduli stabilization
    apply (and are in some ways actually simpler) also at higher
    scales of SUSY breaking. Phenomenological clues do hint
    at low energy SUSY, which would be very interesting to
    discover. But it is important to recognize
    that its absence does not affect the status of
    string theory as a theory of gravity; in fact many of the most
    important developments and open questions in this area, such
    as those involving spacetime singularities, involve supersymmetry
    breaking scales of order the KK or string scale.

  36. chris says:

    hi Chris Oakley,

    to some extent i agree with you. i myself can’t reconcile antropic reasoning with the very nature of physics. but you know, science has strange ways of progressing.

    i always have to think about kepler, e.g. whose middle age mystic speculation about the harmony of spheres ultimately led him to meander his way to find the 3 laws.

    for suskind in particular, i (as a lattice physicist) am confronted with one of his brilliant insights on an almost daily basis. even if he decides to become a spiritual medium tomorrow it does not annul this particular achievment.

    so, yes, i don’t buy any of the stuff he is doing at the moment, but he has definitely ‘made it as a physicist’ no matter what.

  37. Anders R says:

    i don’t understand how you cannot understand something that doesn’t exist. the ultimate string theory must be constructed by humans, and if it hasn’t been constructed yet it doesn’t exist.

  38. Anders R says:

    this was regarding the witten quote:

    “It’s incredibly rich and mostly buried underground. People just know bits and pieces at the surface or that they’ve found by a little bit of digging, even though this so far amounts to an enormous body of knowledge…”

  39. Bee says:

    Hi Anders R: That’s actually an interesting question. I guess it greatly depends on what one means with ‘existence’. In how far does a mathematical structure ‘exist’ before it is understood by humans? Does something ‘exist’ that doesn’t have any (known) relation to ‘reality’ (another ambiguous word)? Does something ‘exist’ that is only an idea, or maybe not even yet an idea, or maybe a not even wrong idea? I think it matters in this context what one is trying to dig out there… Best – B.

  40. Anders R says:

    yeah i guess that if you see mathematics as a sort of structure that mathematicians find out more and more about then it makes more sense.

  41. dan says:

    I understand that string theory does not require SUSY GUT’s, but if LHC does detect SUSY, this would presumably imply some sort of SUSY GUT, which presumably could be embedded in some sort of string theory, and all string theories have a quantum gravity sector. String theorists do not commit themselves to low-energy SUSY phenomology that will be seen at LHC, of course, but should SUSY be seen I’m not sure that calling string theory unification scenarios are failures in that remote event.

    Does string theory succeed as a theory of quantum gravity? I am aware of objections that it is not background independent, nonetheless it does have gravitons.

  42. Peter Woit says:

    dan,

    String theory unification will remain a failure as long as it can’t predict anything, and seeing SUSY at the LHC by itself won’t change that. The only way it will change is if you see SUSY, together with a SUSY breaking pattern that is naturally explained by a specific class of string theory backgrounds. That’s what string theorists are hoping for, but I see zero reason for it other than wishful thinking.

    The debate about background independence and string theory has been carried on at this blog and many others upwards of 100 times by now. Unless there’s something new about this, please don’t start the same discussion all over again here.

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  44. dan says:

    Dear Peter,

    What do you think is the most promising solution to the hierarchy problem if you don’t believe in SUSY? Technicolor models and top quark condensates don’t seem any better than SUSY.

    thanks
    Regards
    Dan

  45. Peter Woit says:

    dan,

    Actually I’ve never been convinced by the arguments about the hierarchy problem. For one thing, we have no strong evidence for a GUT scale. For another, given our lack of knowledge about quantum gravity, we don’t even know that the size Newton’s constant necessarily means that quantum gravity happens at the Planck scale. So, it’s not even clear there’s a problem. To me the real problem has always been that of actually understanding what is causing electroweak symmetry breaking. Once we know that, let’s see if we still have a “hierarchy problem”. Hopefully the LHC will set us on the right track….

  46. dan says:

    Peter,
    thanks for sharing that with me, I think that your view is why some string theorists disagree with you so strongly. While proton decay hasn’t yet been observed as required by GUT’s, stringers believe the matter/antimatter symmetry and violation of baryon number implies some sort of GUT, and that the most popular SUSY-GUT can be embedded in a string theory framework.

    Dan

  47. Eric says:

    Dear Peter,
    It seems that you’ve never heard of radiative electroweak symmetry breaking which occurs in supersymmetric theories, in particular ‘no scale’ supergravity models. The large top quark mass was anticipated 25 years ago when this mechanism was first discovered.

    No compelling evidence for SUSY? How about:

    1) Solution to the hierarchy problem.
    2) Gauge coupling unification.
    3) Well-motivated dark matter candidate
    4) g-2 for the muon
    5) Dyamical electroweak symmetry breaking.

    It’s clear why you’re in the math department and not even a real
    particle physicists.

  48. dan says:

    Eric,

    Peter does address 1-3 in NEW (though I didn’t realize reading NEW that he “never been convinced by the arguments about the hierarchy problem”)

    you may factually disagree with PW, but he does state in NEW, if you bothered to read it, that “Gauge coupling unification” comes off 10 percent too high, and that SUSY “Solution to the hierarchy problem” has its own problems (i.e 105 extra parameters, u problem, symmetry breaking mechanism, ad hoc introduction of R-parity, vacuum energy and cc too high, flavor changing neutral currents, lepton flavor changing, potentially large cp violation). If you bothered to read his book you’d know this.

    DM is compelling evidence for anything.

    Still, PW, I don’t recall you addressed in NEW
    points 4 & 5

    4) g-2 for the muon
    5) Dyamical electroweak symmetry breaking.

    regards
    Dan

  49. Peter Woit says:

    dan,

    I was going to resolve to stop wasting time responding to string theorist trolls like Eric who seem to think that posting bad arguments and personal attacks on me helps their cause.

    Besides the book, one of many places I’ve discussed the issue of supersymmetry is here:

    http://www.math.columbia.edu/~woit/wordpress/?p=97

    It’s a discussion of a talk by Witten I attended on exactly this question. Unlike Eric, Witten did not claim that there is “compelling” evidence for supersymmetry. He gave several very tentative points of evidence for supersymmetry, together with several tentative points of evidence against. He certainly didn’t include Eric’s ridiculous claim that the g-2 discrepancy is compelling evidence for supersymmetry (it isn’t, even assuming it is really there, which is not clear, there are many, many ways of getting such a discrepancy other than supersymmetry). There are various claims about a “prediction” of the top mass from supersymmetry, but this is based on various assumptions and never was much of a “prediction”. I’d have to go look up the history, but from what I remember most discussion of this appeared after the top quark was already discovered. I’m pretty sure that there was never a point at which any supersymmetry partisan ever announced that supersymmetry was wrong if the top mass didn’t have a certain value.

  50. Eric says:

    Dan,
    Peter’s arguments against gauge coupling unification are incredibly misleading. He says that it comes out 10% wrong on the strong coupling if you start out at the estimated unification scale and run the RGE’s to the electroweak scale. However, this ignores the fact that there is an inherent uncertainty (of about 1%) on the actual unifcation scale, as well as an uncertainty on the value of the strong coupling constant at the electroweak scale. Thus if you start at the high scale, you are merely compounding the same uncertainty multiple times.

    As far as the ‘wild-claims’ that SUSY + radiative electroweak symmetry breaking predicts a large top quark mass, this is standard knowledge which you will find in every textbook on the subject. The prediction of the large top mass was done in the early 1980’s, well before there was any other reason to suspect it to be so large.

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