What is Dead?

There is a lot of interesting talk around the blogs about the fate of SUSY and even the whole field of phenomenology. It is a fascinating debate.

The CERN DG had some words of caution to give us during yesterday’s press conference. These are early days for the LHC and we should not imagine that it has already given a definitive report, but it has made some good points along with the Tevatron.

The Higgs sector does not look like what the standard model predicts. There are hints of something in the light mass window but it does not look like the SM Higgs. It does not have sufficient cross-section and may be spread out over too wide a mass range. It is too early to say what that is, or even if anything is really there. Much more data must be collected so that each experiment can separately say what it sees. That could take until the end of next year, but we will certainly have more clues at the end of this year. If the Standard Model is out, then we cannot be sure that some heavier Higgs is not another possibility. It just wont be the SM Higgs.

SUSY predicts a light Higgs but all the searches for missing energy events predicted by SUSY have been negative so far. Does this mean SUSY is dead? Of course is doesn’t. Some of the simpler SUSY models such as MSSM are looking very shaky, but there are other variants. We need some SUSY based fits using all the available data including the Higgs searches. Hopefully the phenomenologists will provide some updates for those soon to let us know what the conclusions are. I have explained in the past that SUSY is a well motivated theory. Many phenomenoligists have put a lot of work into it,  but if the LHC rules it out I am sure they will be the first to give us the right reasons to think so.

I don’t agree that the work of phenomenologists has been a waste of time. Without their research the experiments would not have been able to set up the model based tests that have told us so much. A lot of different ideas apart from SUSY are being tested. They can’t all be right. Following the EPS conference there will be a number of follow-up meetings to discuss the implications (see the Calendar). This will be the time for the theorists to come back and tell us what is left on the table. It will help the experimenters to prioritize the searches they want to put most effort into as more data becomes available.

The parameter space of SUSY is large and flexible but everywhere it describes a Higgs sector that is different from the standard model. That is why I think the Higgs sector is crucial to understanding whether SUSY at the electroweak scale will live or die. That part of the story is still at an early stage. The next chapters in this gripping tale will unfold in the next few months. There could be several unexpected twists on the way.

Update 27-Jul-2011: Tommaso Dorigo has a relevant article about SUSY fits with a pointer to some updates from the MasterCode project

28 Responses to What is Dead?

  1. To me the key question concerns the microscopic description of massivation: the description in terms of Higgs is after all a phenomenological model borrowed from condensed matter physics. The tragedy is that not only MSSM but also QFT limit of super string models assume Higgs mechanism and its generalization. Also inflationary cosmology does this. Several decades of theoretical physics can end up to a trash bin if Higgs based massivation turns out to wrong.

    What happens in the massivation: this is the question. Could it be that all components of Higgs like fields, of its super partners, and of its higher spin generalizations are eaten in a process in which massless multiplets with various spins combine to form only massive multiplets. If so the phenomenon would be purely group theoretical. This would be very elegant realization for a world without Higgs nor its possible higher spin analogs (say spin one analog providing spin 1 states for graviton).

    Here twistor approach might provide the guideline since its applicability requires that massive particles should allow interpretation as bound states of massless ones. This would also automatically bring in IR cutoff possibly resolving the IR singularities plaguing massless gauge theories and making the Yangian symmetry exact. Perhaps the simple observation that spin one bound states of massless fermion and anti-fermion are automatically massive might help to get to the deeper waters.

    p-Adic thermodynamics which for minimal option is just real thermodynamics for conformal weight (to which mass squared is proportional) fixed from the condition that it is equivalent with real thermodynamics is TGD based proposal for the most important but not all aspects of particle massivation and leads to extremely powerful prediction for masses since Boltzman weights must reduce to powers of prime, the allowed values of which are assumed to be near to power of two by p-adic length scale hypothesis. My humble wish is that after these 15 years the failure of Higgs approach might finally make colleagues mature to consider seriously this kind of microscopic description of Higgs mechanism based on first principles and consistent with super-conformal invariance.

  2. Alejandro Rivero says:

    One could argue what waste of time has been bigger, the plank scale approximations of hep-th or the model bric-a-brac of hep-ph. By going Planck just to explain the spin-2 particle in the string model, the hep-th crowd has surely chosen a side without waiting for mother nature to tell us the whole history.

  3. Wilhelmus de Wilde says:

    Like your logic Philip, it is needed in turbulent times that we are living in now (who the hell said that 100 years ago ?), don’t forget that Newton’s gravity is still valuable after Einstein, but just on a smaller scale…

    keep on thinking free


  4. Of course, SUSY in low energy can be saved via reference [1] in http://www.vixra.org/abs/1102.0034 ;-) Back in PF, mitchell porter has put some time to cross the modern bibliography looking for some dinamical mechanism to give support to the conjecture of a compositeness of the susy scalars.

    While I am mostly out of the game, I think we keep an slow but steady progress. Also, recently we started to suspect, that lepton number could be the fourth colour.

  5. Vladimir Kalitvianski says:

    Dead is the gauge way of developing particle physics. I propose you to study my toy problem of “gauge” coupling to see why it is wrong.


    • carla says:

      I can’t see you equations starting on page 5.

      And why all the quotations, starting with how Dirac in middle-age who couldn’t understand the process?

      • Vladimir Kalitvianski says:

        Carla, download and open document, then you will see formulas correctly as well as important comments below the slides. Google document viewer distorts things. This instruction is given in description of my document.

        P. Dirac understood “the process” well. He was the author and a strong physicist. Yo will see it if read my opus.

      • Vlad, the formulae are also unreadable in OpenOffice. Surely something about the fonts.

      • Vladimir Kalitvianski says:

        My OpenOffice shows everything right including comments. There is also PowerPoint viewer free on the net, I think.

    • Lawrence B. Crowell says:

      I don’t think this is a verdict on gauge theory. QCD is well substantiated, and it is the hallmark of non-abelian gauge theories. The data is suggesting that the Higgs boson field is not the appropriate way to understand the phase structure of the vacuum and broken symmetry. With SUSY the phenomenologies which have been hung on it have a bad track record, and this seems to follow suit.

      • Vladimir Kalitvianski says:

        I do not say QED or QCD is completely wrong. I say the gauge way of its constructing is wrong. As lonf as we modify the theory solutions, we in fact are using solutions of a modified theory which we do not know.

      • Felix Lev says:

        The fact that “the gauge way of developing particle physics” is not well substantiated mathematically, has been known for a very long time. One of the obvious reasons: local interacting quantum fields can be treated only as operator distributions but it’s well known that it’s incorrect to multiply distributions at the same point. Another reason is that continuous space-time coordinates are not measurable. One of ideas of the string theory is that if a point (a zero-dimensional object is replaced by a string one-dimensional object) then there is hope that infinities will be less singular. But this does not solve the problem of infinities. Typical objections: 1) the fact that the theory gives 8 correct digits for the anomalous magnetic moments of the electron and muon is much more important than the lack of mathematical rigor; 2) infinities are well understood, etc. My impression is that Lawrence DOES NOT belong to the majority of physicists for whom mathematical rigor means nothing. That’s why I would appreciate if he explains his phrase that QCD is well substantiated.

      • Vladimir Kalitvianski says:

        Felix, product of distributions is infinity; why call it “uncertainty”. It is uncertainty only in one sense – it is larger than any large but finite (certain) number, so it is just infinity. In my essay I show that even finite corrections to the fundamental constants worsen the previous agreement with experiments so the problem is not in their infinite values but in their very presence. I propose to reformulate the theory of particles as a theory of quasi-particles in compound systems. Such a formulation is free from self-action (that is responsible for UV divergences) and is free from IR divergences (nearly exact soft and hard excitations occur automatically (rather than “perturbatively”).

        Any Taylor series with a very small expansion parameter gives similar (high) precision; it is not property of QED solely.

      • Felix Lev says:

        Vladimir, I agree with you: my comment does not contain the word “uncertainty” at all, I am talking about infinities. I will try to understand your approach. My approach can be found in vixra:1104.0065 (Quantum Gravity and String Theory) and in papers in arxiv.

  6. Kea says:

    I give credit to the honest string theorists for having put their opinions on the line. That is the job of a theorist – to predict, not only postdict. But now let us see how many (of them and others) are good enough scientists to recognise nature’s hatchet.

    • Speaking of credit, Kea, it was your report, last year, of the drawings of Davelock which moved me to look again to Koide and notice the 313 MeV thing, which is a second hint that the lepton scale is related to the QCD scale, but is in some way competing against the “supersymmetric” hint, the equality of masses of muon and pion.

      • Kea says:

        Alejandro, from my point of view we are still doing susy theories, such as N=4 SYM. We are just not treating particles, or any other physics, the way the stringers do. I believe my Fourier susy stuff should have some link to your diquark ideas, but it is not a priority for me to figure this out.

  7. To Alexandro:

    Nature has given us very many hints but we have refused to take them seriously;-)!. Just to mention some of the most striking examples about “put it under to rug” policy.

    a) Standard model symmetries have turned out to be stable. Therefore one would have expected the question “What makes standard model gauge group mathematically so special?”. CP_2 geometry of course explains them and also reduces these symmetries to number theory: CP_2 indeed relates naturally to the octonion-quaternion relationship since SU(3) is subgroup of octonionic automorphisms.

    b) Proton seems to be stable but this has been forgotten for all these years. If one takes the stability seriously quarks and lepton correspond to different chiralities of a higher-D spinors. This suggests the imbedding of space-times as surfaces in some higher-D space explaining the standard model quantum numbers. M^4xCP_2 is the unavoidable outcome by a ten-line argument.

    c) This however forces to modify the view about color since it cannot correspond to spin-like quantum number anymore and this leads to the prediction of colored excitations of leptons. Already at seventies a lot of evidence for what I electropions emerged. Later for muopions and 2 and 1/2 years ago for tau pions via CDF anomaly. All this has been systematically forgotten since it does not fit standard model. One could have asked: is our view about color really quite correct?

    e) The explanation of family replication phenomenon in terms of gauge symmetry breaking is extremely un-natural. Consider only the ratio of neutrino mass scale to top quark mass scale: naturality suggests some group theoretic small algebraic number such as sqrt(3). Something else is involved and topology of partonic 2-surface is a natural candidate.

    Particle *mass scale* seems to be dynamical and this vision is beautifully realized in p-adic mass calculations. For instance, particles and sparticles obey the same mass formula but with different p-adic mass scale. But again the vulgar reductionism accepting only one fundamental length scale – the Planck scale- has dominated the scene. It has been impossible for colleagues to accept that fractality could define an alternative form of reductionism.

    I could continue the list but to my view the number of items is enough for a good argument. The basic problem has been that people are nowadays building careers instead of doing science and they simple cannot take any risks. Doing massive mechanical calculations in string theory using symbol manipulation programs produces what looks very much like science. This kind of stuff beats all the arguments above: for the referee these arguments are just pseudoscience since there are no formulas!

    • Matti, I think that the topic here was supersymmetry, not the general issue of hints we are missing from nature, which I agree there are some. Given your need of using a new language as you move on new concepts, I dont get which part of your work is relevant to SUSY.

  8. Sorry for mis-undestanding: in any case the ability of colleagues to miss again and again the hints from Nature have been amazing. Now Lubos is suggesting total cut from what he calls phenomenology. Not very promising.

    TGD predicts a different variant of SUSY. Super-conformal invariance for light-like 3-surfaces is the basic symmetry. The many fermion states assignable to partonic 2-surface representations of SUSY with large number of N but broken badly by the geometry of CP_2. Right handed neutrino generates the least broken SUSY. R-parity associated with nu_R is broken since right and left handed neutrinos mix.

    Although SUSY is not needed to stabilize Higgs mass in TGD, the anomaly of muonic g-2 requires SUSY. The following strongly symmetry inspired picture is what allows rather precise predictions for sfermion masses.

    a) In TGD based SUSY mass formulas are same for particles and sparticles and only the p-adic length scale is different.
    This resolves the extremely problematic massivation issued of supersymmetric QFTs.

    b) Ordinary leptons are characterized by Mersennes or Gaussian Mersennes: (M_{127},M_{G,113}, M_{107}) for (e,mu,tau). If also sleptons correspond to Mersennes of Gaussian Mersennes, then (selectron, smuon, stau) should correspond to (M_{89},M_{G,79},M_{61}) is one assumes that selectron corresponds to M_{89}. Selectron mass would be 250 GeV and smuon mass 13.9 TeV. g-2 anomaly for muon suggests that the mass of selectron should not be much above .1 TeV and M_{89} indeed fits the bill. Valence quarks correspond to the Gaussian Mersenne k>= 113, which suggests that squarks have k>= 79 so that squark masses should be above 13 TeV. If sneutrinos correspond to Gaussian Mersenne k=167 then sneutrinos could have mass below electron mass scale. Selectron would remain the only experiment signature of TGD SUSY at this moment.

    c) One decay channel for selectron would be to electron+ sZ or neutrino+ sW. sZ/sW would eventually decay to possibly virtual Z+ neutrino/W+neutrino: that is weak gauge boson plus missing energy. Neutralino and chargino need not decay in the detection volume. The lower bound for neutralino mass is 46 GeV from intermediate gauge boson decay widths. Hence this option is not excluded by experimental facts.

    250 GeV selectron remains the prediction testable at LHC. There is some evidence for 250 GeV bump but I have not looked whether it could be interpreted in terms of selectron.

    • Alejandro Rivero says:

      Ok I see. So in principle your TGD does not require SUSY but can do extra predictions is SUSY is postulated, isn’t it? An then you argue that an experimental input, the muon g-2 anomaly, actually needs SUSY. Does this argument depends on TGD or is it generic?

  9. Addition to the remark at the end of the previous posting: 250 GeV bump was mentioned by Lubos but it appeared in ZZ channel so that the situation is completely open to my best knowledge.

  10. Wilhelmus de Wilde says:

    I would like to know your anwers about the fact that both string theory and LQG predict that space-time is not smooth but “grainy” at extremely small scales ( New Scientist 9 july 2011) this scale is to be the Planck Scale , however in the same article it is stated that by the study of GRB (gamma Ray Burst) the limit of the size of these grains of space time is 10^-48m, instead of the Planck length of 10^-35m, is this influencing the mathematics of string theory and what about the extra dimensions that would appear below the Planck length ? Are there different forms of Death ?



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