# April Fools at the APS Meeting in Atlanta

From the latest Science News:

String theory weighs in on Higgs

ATLANTA – Physicists working on big experiments at particle colliders aren’t the only ones who have something to say about the mass of the elusive Higgs boson. A theorist has now thrown his hat into the ring. Theoretical physicist Gordon Kane of the University of Michigan in Ann Arbor reported April 1 that he and colleagues have calculated the mass of the Higgs from the principles of string theory, with no additional inputs. In the standard model of particle physics, the Higgs boson is required for other particles to have mass. Kane’s team, which also reported the calculation online last December at arXiv.org, put the mass at between 105 billion and 129 billion electron volts. The proposed mass is consistent with hints of a Higgs at around 125 billion electron volts, reported later that same month by both the Atlas and CMS teams at the Large Hadron Collider near Geneva. “This is the first string theory prediction for the mass of the Higgs — ever,” Kane said.

For some background on this, see here.

Update: It seems that this joke is far more elaborate than I had realized. The APS this year awarded Kane the Julius Edgar Lilienfeld Prize, and then scheduled him to deliver the Prize speech on April Fools day. His speech abstract is:

The Higgs Boson, String Theory, and the Real World

In this talk I’ll describe how string theory is exciting because it can address most, perhaps all, of the questions we hope to understand about our world: why quarks and leptons make up our world, what forces form our world, cosmology, parity violation, and much more. I’ll explain why string theory is testable in basically the same ways as the rest of physics, and why much of what is written about that is misleading. String theory is already or soon being tested in several ways, including correctly predicting the recently observed Higgs boson properties and mass, and predictions for dark matter, LHC physics, cosmological history, and more, from work in the increasingly active subfield “string phenomenology.”

His presentation advertises in large red letters:

First String/M-theory tested prediction for new physics — predicted 125 Gev (August)

and claims that you shouldn’t believe arguments that string theory is untestable, even when they come from string theorists:

If your impression of string theory came from some popular books and articles and blogs (or from formal string theorists) you might be suspicious of taking string theory explanations seriously.

He has many slides explaining the supposed “125 GeV Higgs Mass Prediction”, but I can’t see an argument that gives 125 GeV, and it’s a prediction that suspiciously comes without error bars. The closest thing to a bottom line seems to be page 30, where the “Blue dots are favored prediction”, and these blue dots span a Higgs mass range of about 121-128 GeV, so maybe he means 125 +/- 4 or something like that. There are also a lot of red dots from 105 GeV to 121 GeV, which the theory “disfavors”, “but doesn’t yet rule out”.

The other LHC predictions he makes are that the squarks are up around 30 TeV, so unobservable at the LHC, and that the gluino is light enough to be seen at the LHC. His “generic LHC predictions” plot has a gluino around 600 GeV, at a value that has already been ruled out by LHC results. Back in December, he was predicting “a few months” until he was vindicated by observation of a light gluino. If 4 is a “few”, his time is up.

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### 48 Responses to April Fools at the APS Meeting in Atlanta

1. Bernhard says:

Either then already knowing the results, of course.

“reported later that same month”

What a shameful campaign, what a big liar Kane is. The guy makes a postdiction and sell it as a prediction. Shameful, shameful.

2. Peter Woit says:

Bernhard,

When, after decades of trying to find a string theory prediction for the Higgs mass, Kane came up with one just days before the number was publicly announced (although also days after it was described here…), I thought that was pretty strange and hard to understand. However, it is now clear what was going on: he was just setting up an April Fool’s joke! It’s definitely about the most successful one I’ve seen, had lots of people fooled.

3. harryb says:

It does show however the fine line that ST continues to run, and how it erodes away at science – its very obscurity makes it ever harder to discern ST from its own ironic counterpart

4. Aspirin says:

Kane is of course the King of String Theory Hype so this is hardly surprising. At this point he is just sullying the reputation of arXiv. I am surprised people like Witten haven’t called him out as an embarrassment to the community.

5. Mike says:

Sadly, the April fool’s joke is on the world, for being beguiled for many years by false predictions from string theorists. I think we laid some of this to rest last year with no evidence of SUSY and no gluinos. How long will people continue to ignore experimental evidence? If the excess at 125 GeV starts going down, all of the postdiction-prophets showing their theory’s prediction at this energy should be looking for new jobs.

6. P says:

Groan groan groan groan groan. Some of the comments on this blog make people’s biases extremely clear. Some of you are so anti-string-hype (I’m anti-string-hype as well, though not anti-string) that you haven’t done your homework or even considered the fact that Kane et al did a field theory computation that had assumptions and consequences.

First, let me be clear: I’m not criticizing Peter on this issue, as he seems to have done some of his homework in the previous post on Kane’s scenario, even though this post of his a bit of a rant. Second, I’m not a fan of hyping Kane’s scenario as a unique prediction of string theory. It’s not.

Criticisms:

@ Bernhard: Do your homework! You imply it’s a “postdiction” because you think Kane only made these claims after the Higgs rumors came out. That’s manifestly not the truth. Peter links to Kane’s slides where he is clear that he was talking about this Higgs result at a conference in August. You can go to those slides from Madison in August and see that his 122-129 GeV range was discussed months before the Higgs rumors came out.

@Peter: Okay, one criticism of Peter. In these comments you seem to imply that Kane’s claims were only made two weeks before, when (I think) you know he made these claims months before the Higgs rumors came out.

@ Aspirin: I don’t disagree with you. He’s overhyping and perhaps a big shot like Witten should make a clear statement about these things.

@Mike: Same comment as with Bernhard. Even though it’s not a unique prediction of string theory, as he would like to hype, it’s a bold-faced lie to say it came after the Higgs rumors came out.

Can we not talk honestly about science anymore? Are we really reduced to just attacking some person because he overhypes something without us really understanding the assumptions he made?

Make no mistake about it – Kane’s scenario is not a “unique prediction” of string theory – but he and his collaborators actually make field theoretic assumptions and did a computation, and the consequences of the assumed field theoretic structure (that he claims is generic in string theory) is a 122-129 GeV SM-like Higgs if tan beta >= 7. Regardless of hype, this is a computation! In field theory! With a Lagrangian! They run coupling constants and impose cosmological constraints! And no one on here has even mentioned that yet. Particle physicists have taken SUGRA very seriously for thirty years and this is precisely the framework for Kane’s paper. It just so happens that string theory gives rise to SUGRA, but SUGRA can be studied independently as well.

All of this is to say: regardless of claims about string theory, if a field theory calculation they did with some assumptions about moduli masses due to honest cosmological bounds (amongst other things) gave m_H in a given range, this is an interesting result.

Now I ask you all a question: Peter raised in the previous blog post that he doesn’t know why Kane emphasizes tan beta > 7. I don’t either, though Kane in his slides claims its phenomenologically preferred over low tan beta. Does anyone else know why this is?

Sorry for the rant. I just really hope we can raise the bar above blind criticism without understanding what he and collaborators did. That’s not how we should discuss science.

Hype? Criticize away . . .

7. Mark says:

@P, if \tan\beta ~O(1) then the Higgsinos (the mu-term) are too heavy and the “little hierarchy” problem gets worse. So, having an intermediate range \tan\beta alleviates the little hierarchy problem in the split SUSY scenario of Kane et.al.

8. Clara says:

Peter,

who is on the Prize committee? Is it possible to find out?

9. Bernhard says:

P,

“@ Bernhard: ….
Peter links to Kane’s slides where he is clear that he was talking about this Higgs result at a conference in August. You can go to those slides from Madison in August and see that his 122-129 GeV range was discussed months before the Higgs rumors came out.”

I did. Here´s what is written “There’s nothing in Kane’s August talk about a 122-129 GeV range for the Higgs mass, but in the December 5 paper it appears explicitly three times”

In any case don´t worry about the Higgs, since the gluinos he predicted were not found , I now believe Kane 100%, I think “string theory is testable in basically the same ways as the rest of physics” and that because of it, is ruled out.

10. Igor Khavkine says:

Looking through the prize citations of past Lilienfeld Prize winners, it seems that what they mostly have in common is being active popularizers or science.

11. Bernhard says:

P,

sorry. What you mentioned was the slides themselves. I of course did look at the time, and it is exactly what Peter said.

One more thing, who took or takes SUGRA seriously? In my opinion, this is a framework experimentalists love for the low number of parameters, not that people were really taking it seriously.

12. Ralph says:

I predict that the Higg’s mass is within 20% of the hints seen from LHC last year.
Ta.
R.
PS. I know what next weeks winning lottery numbers are. I’ll prove that to you in May. wink. wink.

13. P says:

@ Mark: thanks! Simple enough answer . . . sounds good.

@Bernhard: I understand your objection now. For some reason, you’re upset that he put error bars in his December paper, saying 122-129 GeV rather than “about 127 GeV”. True, “about” is not a precise error bar, but are you really going to take issue with the fact that he said 127 GeV and “about”, while the supposed observed value is 125.5GeV? I don’t take issue with this. These were conference slides, and he was loose about it.

Regarding your remarks about gluinos: can show me the paper which makes the same assumptions as Kane’s field theory model and rules out gluino? I just took at look at all ATLAS papers with the word gluino in the title and found nothing of that sort. Perhaps there is something from CMS or LHCb that definitively rules out light gluinos (below a TeV?), period. If so, show me. If not, we should still be very conservative about what we say about the LHC and SUSY. It’s still in the early days of the experiment and they make very strong assumptions about their analyses that only apply to a fraction of SUSY parameter space. In my opinion, the joy of experiment is that it’s not worth philosophizing too much now based on early analyses, but in a number of years we’ll definitely know the answers.

Regarding SUGRA – I’m no supergravity expert, but I think you’re mixing up SUGRA and mSUGRA. The latter has a small number of parameters and does some very interesting things, including the dynamic generation of an ESWB Higgs potential. SUGRA itself . . . I believe really anyone who takes SUSY seriously takes SUGRA seriously. And there are many, many non string-theorists who take SUSY seriously.

14. P says:

Also, for those that haven’t looked back at the previous post on this subject, Mark’s comments are particularly good and are worth a read. He seems to have really tried to understand what Kane et al actually did, as opposed to just getting angry at the hype.

http://www.math.columbia.edu/~woit/wordpress/?p=4262

15. Peter Woit says:

Aspirin,

One place where authorities do weigh in is when Kane tries to publish this in a reputable journal. It seems likely that he would have immediately sent this to PRL at the beginning of December. As far as I can tell, it is still unpublished. When and if it is published somewhere, it may be interesting to compare the published version of the paper to the arXiv version, to see what changes the referees insist on. There’s a history of string theorists (see the Distler et al story back in 2007) having referees refuse to let them publish their “string theory predictions”, but then going ahead and issuing press releases about them anyway.

16. Peter Woit says:

Clara,

The prize committee is on the web-page I linked to. To be fair to them, they decided on Kane and announced the prize before he pulled this stunt in December. Maybe the later decision to schedule his talk for April 1 wasn’t a coincidence…

17. Bernhard says:

P,

about SUGRA and mSUGRA, point taken, for some reason I assumed you were talking about mSUGRA since ATLAS and CMS are continuously using it. My mistake.

About gluinos, you should listen to what Kane himself said about it. According to his own predictions we should have seen some light gluinos already. If I believe parameters can be easily played with to adapt, sure, but that is the whole point with the non predictability of the theory.

About the hype. Well, this is my SINGLE problem. Papers like Kane´s that play with parameters and make Higgs predictions are many. In the old thread you can see many posted much older papers that make the same- I take it back, much better prediction about the Higgs mass but before a larger fraction of the parameter space being ruled out. Kane made a much stronger case about the exact mass value after the rumors and in any case even if we ignore this, and I´m willing to, there is absolutely no point in making the circus he is doing around this, otherwise every single phenomenologist that got the mass Higgs right should immediately get the Nobel, specially considering their predictions beat Kane´s in years.

All in all, I still think string theory says nothing, zip, nada, about the real world.

18. Peter Woit says:

P,

As I think I’ve made clear elsewhere, all I can see that Kane really has is a complicated calculation in a specific model implying the Higgs mass should be below about 130 GeV, something which was experimentally indicated already when he started making these claims last August. The “122-129″ business just appears in the early December paper, after the 125 number was known. The public claims he has been making about having a prediction of “125” before the results were known are just outrageous.

Also in the August slides, there’s some sort of “prediction” of a 600 GeV gluino, which I believe has been ruled out by now. Kane conveniently doesn’t mention that.

He has been promoting “string theory predictions” of masses of new particles for 20 or more years (see his famous “supertestable” article in Physics Today back in 1997). These “predictions” keep changing, moving up as experimental results come in showing them to be wrong. I guess one easy prediction for anyone to make a few years ago would be that even if the LHC found no superpartners, for the one SM thing it would find (the Higgs), Kane would be there with string theory “predictions” covering the allowable range as it shrunk to the right value.

19. P says:

@ Bernhard:

Thanks for the thoughtful response. I think we see eye to eye on SUGRA vs mSUGRA now. Not to say that mSUGRA isn’t interesting in it’s own right.

Regarding gluinos: which Kane comments are you referring to? I’ll take a look at whatever source you send me. Also, in the most conservative experimental sense, everything we can say about not having seen gluinos is in those papers, and the analyses seem to be in very limited frameworks, most of which don’t apply to Kane’s comments. (I haven’t seen one, please show me if there is one!). Though rumors are exciting, I try to limit my thoughts about the existence or non-existence of hypothetical particles to what the experiments have actually said.

Regarding pheno papers: do you have examples from many years ago of serious phenomenologists who strongly pushed for 120-130 GeV SM-like Higgs in a SUSY framework? I’d be curious to see this. SUSY theorists like to talk about light Higgs, and I had really first heard about the stated m_H scenario in press releases (ugh) from Kane et al.

Regardless, hype – yes, it’s an enormous disservice to both the string and the non-string community.

Regarding strings – depending on how nuanced you make your statement, our opinions probably differ. Saying that strings will definitely tell you something about scattering amplitudes at low energies (see: our experiments :)) that a field theory model COULDN’T is . . . well, a hell of a claim. There is good work, though, studying stringy scattering amplitudes at the string scale, and they consider M_s ~ O(TeV). It likely is much higher.

The reason for hope, I believe, is that compactified string theory DOES generically give rise to all of the ingredients we see in our world: non-abelian gauge theories, GR as a limit of quantum gravity, and scalar fields which could be of cosmological importance. True, your coming criticism that it hasn’t yet singled out OUR gauge theory or OUR cosmology is a good one (and it may never), but of course field theory doesn’t do this either . . . and moreover nothing in field theory requires the existence of gauge theories , GR, or scalar fields – they’re input. In string theory, they’re output. This compelling, and I think that if there were any other framework for physics that naturally gave rise to these three things as the output of fundamental principles, string theorists would take it seriously.

Actually, it is possible to use string theory to make falsifiable predictions about the LHC. I made one back in 2007.

I’m especially proud that I already in 2007 could predict that poor Lubos would lose his experimental-susy-by-2006 bet, considering the he evidently hasn’t realized it himself yet.

21. Anon says:

I know it sounds like a cliche, but “history will determine the truth”.

You can’t enforce truth by effective policing.

22. Shantanu says:

Peter, have you look at Susskind’s talks at the KITP conference on bits/branes/black holes?

23. Peter Woit says:

Shantanu,

Not my kind of thing, but others might enjoy. Sounds like he’s getting into the “philosophy of cosmology” business. If he’d stop saying mean things about religion, he’d be a natural for the Templeton Prize.

24. P says:

@ Peter:

Sorry, I didn’t see your post from earlier in response to me. Clearly you’re not a fan of Kane, and I’m also not a fan of the hype.

So I’m still not sure what you’re really taking issue with regarding the slides from August. He clearly says 127GeV in those slides, and if you want to nitpick about 125.5 GeV and 127 GeV, that’s fine, and you can take issue with that. In my mind, the thing that’s interesting about the current location of the bump isn’t that it’s 125.5 and not 127 or 125 – it’s that it’s significantly about the 115-118 GeV often preferred by SUSY theorists (who might have told you SUSY like it below 100 pre-LEP).

25. Peter Woit says:

P.,

The “127” is not explained in the slides, and it doesn’t appear in the paper. If “127” is the first actual prediction from string theory, it would be nice if Kane would explain the 127 in his paper. It would also be nice if he wouldn’t call “127” “125”. Again, the bottom line in his paper appears to me to be a graph of points covering the Higgs mass range from 105 to 128 GeV. If the LHC had found a signal at 118 GeV, I have no doubt Kane would have produced a paper about how that number was a “string theory prediction”.

26. P says:

Peter,

Indeed, in his short talk he spends time explaining his setup and assumptions, discussing the masses of various particles that go into his RGE analysis. Then, at the end, he states the conclusions of the scenarios: heavy scalars, light gluinos, and a single light higgs boson with mass around 127 GeV. Now, if you want to be cynical and say the last number was complete lie and not the result of any analysis, that’s fine. To me it seems more plausible that it is the result of an actual analysis, details not included in the paper because of time spent motivating the setup.

Do you think the “about 127″ is actually a lie, not the result of an analysis that he didn’t present in the slides?

Also, regarding your remarks about the gluinos of his scenario being ruled out: show me the paper that makes the same assumptions as his model. Some ATLAS papers clearly do not make the same assumptions. They may very well have ruled out his model, but I haven’t seen it.

Cheers,
P

27. P says:

Also, sorry to be a stickler about this, but again, the surprising thing about “about 127″ or the “125.5 +- error bars” is that it’s a heavier Higgs than expected by most SUSY theorists.

For historical comparison: the ever useful Wikipedia (someone should check PDG) tells me that the error bars on the top quark mass are +- 1.5 GeV. Even if you want to ignore the “about” in “about 127″, a 1.5 GeV discrepancy is not uncommon. In fact, though CMS was originally worried about being 2 GeV or so lower than ATLAS for m_H, this caused some worry but not enough to make strong statements. So I don’t understand why you’re harping on this.

Regarding claims that it is generic in string theory, I’m not sure, and in fact I’m skeptical and definitely think he shouldn’t be hyping it. But I don’t question the results of a field theory analysis.

28. Peter Woit says:

P,

I simply don’t know what the argument for the 127 is. The situation here is that you are claiming that Kane had a good argument solving the biggest problem in particle theory, fixing the Higgs mass at 127 back in August using string theory, but didn’t bother to give details of it in his talk or publish it. Then, several days after the 125 news came out, he puts out a paper with no 127 in it, but with an argument for 105-129, with above 122 “preferred”. He then uses this to launch a publicity campaign claiming that he predicted from string theory the “125” long before it was announced. People can draw conclusions from those facts.

I also have no idea what his “string theory predictions” for gluinos are. He has a plot showing what appears to be about 600 GeV for the mass, was publicly claiming back in December that confirmation of his predictions was imminent, now acknowledges in his slides that “current limit for gluinos from string/M theory about 700 GeV” (page 33).

Yes, it’s a heavier Higgs than you get from other popular string theory models. If the LHC had found a lower value, Kane would be giving talks about how string theory predicted the Higgs mass using those models.

I’m not arguing about what a reasonable size of error bars is here, either experimentally or theoretically, just pointing out that he never gives any error bars on his “string theory predictions”.

29. anon. says:

CMS PAS SUS-11-020 excludes gluinos decaying through top quarks up to somewhat more than 800 GeV. ATLAS CONF 2012-004 sets ~ 700 GeV limits on gluinos decaying to stop/chargino, which is a similar topology to what you could get in the model under discussion. Standard jets + missing ET searches also set limits. Gluinos decaying to b+bbar+neutralino are excluded to ~900 GeV by 1203.6193 from ATLAS. Depending on branching ratios for gluino -> t+tbar+neutralino versus gluino -> t+bbar+chargino, you might not find an official CMS or ATLAS result excluding this scenario, but the gluino mass bound is probably ~ 800 GeV or higher, independent of all these details.

It would be a real stretch to say there’s a sharp prediction of the gluino mass in these models, so you can’t really say this rules them out. It’s above what Kane was predicting a year or so ago, though.

Aside from the various overly strong claims, there are some basic facts that are worth bearing in mind:
* A Higgs mass of 125 GeV in the MSSM requires large mass parameters in the stop sector. This could be a very large A-term, with somewhat light stops. But it seems increasingly plausible that if the MSSM is right, some variation on split SUSY is the right model to be thinking about, with scalars in the range from ~ 10 TeV to 1000 TeV. The upper end of that range only fits a 125 GeV Higgs if tan beta is quite close to 1.
* The one input string theory really provides is that it suggests the existence of moduli, i.e. of scalar fields coupling with gravitational strength. With that ingredient, standard effective field theory tells you that they probably have a mass near the gravitino mass and that this is a cosmological disaster unless the gravitino mass is ~ 30 TeV or higher.
* As observed by Randall & Sundrum in 1998, anomaly mediated SUSY breaking can make a 30 TeV gravitino consistent with ~ 1 TeV gauginos, and moduli decays can then produce dark matter (as explained by Moroi & Randall).
* And, as Giudice, Luty, Murayama, & Rattazzi noted in their simultaneous work on anomaly mediation, such a scenario can plausibly lead to scalars a loop factor heavier than gauginos. This kind of scenario was also studied by James Wells, and then Arkani-Hamed & Dimopoulos.

So, if we relax our idea that electroweak symmetry breaking should be completely natural, we have a supersymmetric scenario consistent with the measured Higgs mass and the observed fact that gauge couplings in the MSSM unify. The scalars are quite heavy but the gauginos may be in reach of the LHC. The moduli problem is solved, and flavor isn’t quite as bad as in standard scenarios.

This basic idea was already around in 1998/99. Kane has essentially advocated a specific version of it, tied to a particular model of moduli stabilization. It’s not quite identical to the preexisting split SUSY idea, since he has contributions to gaugino masses not coming from anomaly mediation, but of the same order. But it’s basically a(n idiosyncratic, overhyped) variation on an idea that has been recognized as important for a decade.

30. Peter Woit says:

anon,

Thanks for the very helpful explanations.

31. alsoanon says:

An addition to anon. above. Even the large threshold corrections to the anomaly mediated gaugino masses is not a novel feature of the Kane model. Arkani-Hamed, Giudice and Delgado introduced the “simplest split susy” model in Jan 06, with one-loop splitting between scalars and gauginos, but also higgsinos around the same scale as the scalars, which completely changes the anomaly-mediated gaugino spectrum. Another point: as can be seen from the plots in Giudice and Strumia ‘s paper, http://arxiv.org/pdf/1108.6077.pdf, figure 3, stops at a few hundred TeV (as expected from the one-loop splitting ) give a higgs near 125 GeV for a reasonable tan beta around 2-3. Taking tan beta close to 1 allows scalars nearer to 10,000 TeV.

32. Mark says:

I have studied the papers of Acharya et al and have heard several talks on the topic and I must say that to me the Higgs mass is the least interesting part of the whole story. To me, the most appealing feature of their construction is its simplicity and that it solves many problems simultaneously and in a natural way, the biggest of the problems addressed being the Hierarchy problem. Kane mentions some of those things in his slides so I’m not going to repeat them. However, I wanted to correct the previous poster that in these G2 vacua the gravitino mass scale is constrained to O(10-100) TeV *not* by the relation between the moduli masses and cosmology but instead by the requirement that the leading tree-level contribution to the vacuum energy is tuned to be of the same order of magnitude as the leading one-loop contributions so they could mutually cancel, combined with the constraint on the value of the seven-dimensional volume, which comes from the relation between \alpha_GUT, M_Planck and M_11. In these vacua, when one combines those two together one gets the above constraint on the gravitino mass. I think that it is quite non-trivial that the constraint on the cosmological constant plays a key role in constraining the gravitino mass and it should not be overlooked. Regarding the gaugino masses, just to be more precise, the anomaly mediated terms, which are typically discussed in the literature do not include the Konishi anomaly contribution since people always assumed some sort of sequestering. In the G2-MSSM there is no sequestering and the Konishi anomaly contribution to the gaugino masses is quite large and is directly proportional to the (large) tree-level reduced trilinear terms. So apart from the heavy scalars and trilinears, there is some non-trivial interplay between the trilinear couplings and the gaugino mass spectrum.

33. anonymous says:

Good science cares about explanation. Whether an explanation is a prediction or a “postdiction” is just a historical accident. There are plenty of postdictions that are good science, BCS theory of superconductivity being the first example that comes to my mind. The problem with Kane’s paper isn’t the timing (although that’s maybe reason to be suspicious) as much as it is what Peter notes, that the paper pulls 127 GeV out of thin air, not really explaining anything.

By the way, Peter, I heard Erik Verlinde give a well-attended talk at Caltech yesterday. I know you’ve posted here about his entropic gravity before, so perhaps you would like an update. He said gravity as entropic force would come from string theory, but I took that to mean any underlying microscopic degrees of freedom from unknown physics. The more interesting new contribution was for dark matter. We know how Unruh temperature and Hawking temperature are proportional to accelerations and related to Rindler and black hole horizons, respectively. Verlinde applied the same logic to the cosmological horizon to get a temperature/acceleration. He didn’t show all the details, but apparently the acceleration matched the a_0 of MOND. Someone asked how to cope with the Bullet Cluster, and he managed to brush it aside as not in thermal equilibrium. He also at the very end wrote on the board with no derivation a relation between baryonic matter and the inferred dark matter:
Omega_b=(pi/4)*Omega_DM^2
Someone else, Sean Carroll I think, asked how this relation could be time-independent. This question seemed to take Verlinde by surprise. The abstract for the talk advertised dark energy as well, but this was not really covered in the talk.

34. Peter Woit says:

anonymous,

Thanks for the update on Verlinde. I’m curious whether much of the audience found him convincing.

In a case where one has a completely clear argument, with assumptions stated explicitly and justification given for them, then of course even a postdiction can be completely convincing. Probably the main reason for being skeptical of string phenomenology models is not that they don’t make solid predictions, but that they don’t even make any convincing postdictions. If there was even one of the numbers characterizing the SM that had a convincing string theory explanation, that would carry a lot of weight.

Unfortunately, human minds being what they are, it’s all too easy to come up with a bogus “explanation” of a number once you know the number. Thus the weight assigned to predictions over postdictions.

35. Chris Austin says:

Does anyone know how Kane et al propose to fit the small value of the cosmological constant, given that there are no fluxes in their G2-MSSM scenario?

36. Peter Woit says:

Chris,

Looking at page 39 of his APS presentation, the answer seems to be that he proposes to just set the CC to zero and ignore the problem.

37. S says:

Chris,
This exact question was brought up at the KITP String Phenomenology meeting back in 2010. A plausible mechanism, where the CC scan is due contributions from gauge degrees of freedom in multiple hidden sectors, was briefly discussed in this talk (watch from 41:50 to 43:30): http://online.kitp.ucsb.edu/online/spheno_m10/bobkov/rm/flashtv.html

38. Anonyrat says:

Is the instability/”fine-tuning” problem in QFT an artifact of perturbation theory, or is it a genuine physical problem?

39. Peter Woit says:

Anonyrat,

The explanation of the “fine-tuning” problem in terms of quadratic perturbation theory divergences does look like it might be an artifact of perturbation theory. Another version of the problem though doesn’t depend on perturbation theory: the ratio of the Higgs masss (or electroweak breaking scale) to either the GUT or Planck scale is a very small number, with no symmetry to explain it being almost zero. That’s one motivation for SUSY, where SUSY is supposed to relate the Higgs to fermions with masses small because of chiral symmetry (this argument is potentially ruined by the SUSY breaking scale being too high).

My problem with this argument has always been that it’s not clear why one should take it seriously: we don’t know there even is a GUT, or a GUT scale for GUT symmetry breaking, and we have no idea what the relevance of the Planck scale or quantum gravity really is to the Higgs until we have a unified theory. Much of the argument for why the Higgs mass is “unnatural” seems to depend upon unification schemes for which there is no evidence.

40. Shantanu says:

Peter, interesting that string theory also predicts MOND. (I thought it predicted
supersymmetry and dark matter)

41. Chris Austin says:

Peter and S, thanks.

42. Bernhard says:

A bit old news, so perhaps already pointed out already. Sounds like a boring code problem somewhere, but who knows.

http://www.guardian.co.uk/science/life-and-physics/2012/apr/01/1

43. Marcus says:

I noticed this on the arxiv today:
http://arxiv.org/abs/1204.2795
Compactified String Theories — Generic Predictions for Particle Physics
Bobby Samir Acharya, Gordon Kane, Piyush Kumar
(Submitted on 12 Apr 2012)
In recent years it has been realized that in string/$M$ theories compactified to four dimensions which satisfy cosmological constraints, it is possible to make some generic predictions for particle physics and dark matter: a non-thermal cosmological history before primordial nucleosynthesis, a scale of supersymmetry breaking which is “high” as in gravity mediation, scalar superpartners too heavy to be produced at the LHC (although gluino production is expected in many cases), and a significant fraction of dark matter in the form of axions. When the matter and gauge spectrum below the compactification scale is that of the MSSM, a robust prediction of about 125 GeV for the Higgs boson mass, predictions for various aspects of dark matter physics, as well as predictions for future precision measurements, can be made. As a prototypical example, M theory compactified on a manifold of G_2 holonomy leads to a good candidate for our “string vacuum”, with the TeV scale emerging from the Planck scale, a de Sitter vacuum, robust electroweak symmetry breaking, and solutions of the weak and strong CP problems. In this article we review how these and other results were derived, from the key theoretical ideas to the final phenomenological predictions.
Comments: 30 pages, 1 figure. Invited Review for International Journal of Modern Physics A

44. Luke says:

Thanks for the reference, Marcus! This is a very nice review article and contains a good summary of what’s been known for some time about generic string vacua that result in N=1 D=4 supergravity. The main lesson being that the moduli masses and the gravitino mass are extremely hard to decouple, hence the non-thermal pre BBN cosmological history of the universe with moduli-domination at late times should take over after the radiation domination era, contrary to the standard cosmological picture, hence the axion overabundance problem for f_pq~M_GUT is naturally solved by the entropy dilution due to the moduli decays. Also, the absence of sequestering in string theory coupled with the limits on the gravitino mass from cosmology implies heavy scalars together with the Higgs mass somewhere above 120GeV, if one assumes the MSSM spectrum.

45. Peter Woit says:

Marcus,

I took a fairly close look at that last night. The Higgs mass “prediction” is based on the same plot as before, with, after various assumptions, masses between 105 and 129 GeV, with those above 121 GeV “favored”. According to Kane, string theory now predicts only one non-SM effect observable at the LHC, gluinos, and he’s cagey about them. In 1997 he was predicting 250 GeV gluinos based on string theory, last year they were supposed to be at 600 GeV, by December their observation was a “few months” away. Now they seem to be at “less than or about 1 GeV” and “should be observable with 2012 data”. Once the 2012 data is in, I’m sure an explanation will be found for why string theory “predicts” that their mass is above the LHC bounds.

46. guest says:

I really like how they simultaneously solved both strong CP and supersymmetric (weak) CP problems in one stoke. I was unaware of this connection before and I think it’s pretty neat that they found it.

47. Vince says:

Peter,

Jester has posted about a possible dark matter signal from FERMI. Lubos has posted about it as well, and claims that Gordon Kane can explain it with stringy physics. I wonder: If this does turn out to be a genuine dark matter signal, does this new particle show up in Kane’s earlier paper about how M-theory implies the right range for the Higgs mass (according to the LHC’s results)? If not, does this new particle imply that M-theory is wrong?

48. Peter Woit says:

Vince,

I recommend Jester’s (Resonaances blog) article for anyone interested in this. I’m not convinced by the signal, would be more convincing if this were coming from the experiment itself, will be interesting to see what they have to say.

About Gordon Kane’s claims to explain this with string theory, he can explain anything with string theory. You can’t falsify a theory that predicts anything you want.