Of Particular Significance

Remember That “Blow” to Supersymmetry (And Other Theories)?

POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON 11/16/2012

According to the BBC, it was a heavy blow.  According to a member of the LHCb experiment quoted in the article, it put the theory “in the hospital.”  The reality?  Nobody even suffered a scratch.

On Monday I wrote about a new measurement by the LHCb experiment at the Large Hadron Collider [LHC] of a rare process, reported at the HCP 2012 conference in Kyoto (a link to the talks can be found at this link), in which a B_s meson decays to a muon and an anti-muon (click here for more details of the physics process.)  It’s a very important measurement, definitely!  But whilelistening to theorist Gino Isidori’s talk in which he briefly discussed this measurement, I was a little puzzled about an inconsistency between what LHCb had done and said in the past, and what they had done and were saying now, in particular as was reported/implied by the BBC.

When I chatted with him later, Isidori reminded me exactly what LHCb reported in March, and how it compares to what they report now.

  • March: LHCb reported that at most 4.5 per billion B_s mesons decay this way (at 95% confidence)
  • November: LHCb reports about 3.5 per billion B_s mesons decay this way, and at 95% confidence the rate is at least 1.1 per billion and at most 6.4 per billion.

Notice that the new measurement raises the upper limit on how often this process occurs.  This upward shift is not an indication of a problem; it’s probably just an ordinary statistical effect that arises from having small amounts of data.  But it makes the constraints from this measurement — on the many variants of supersymmetry, and on other theories — a little weaker, if anything.  Most of the supersymmetric (and other) models that would be constrained by this measurement lead to a higher rate than in the Standard Model (where it is predicted to be about 3.2 ± 0.3 per billion).  So a higher upper limit means fewer of these variants are excluded by the data.  All in all,  the constraints on supersymmetric (and other) models are little changed, and perhaps somewhat weaker than they were in March.  Isidori and his colleagues have worked this out, and I’ll try to get details from them next week.

No need to take my word for it, or even Isidori’s.  Professor Michelangelo Mangano of CERN, apparently having spoken independently to other experts, made exactly the same point on page 41 of his summary talk concluding the conference.  (By the way, it was a great talk, and I recommend that experts read it.) 

Well!  So much for the big BBC headline!  [Most likely the public will never learn about this; a news report describing more accurately what this really means for supersymmetry etc. probably will not appear at all on the BBC, and even if it does, it certainly won’t get a big attention-grabbing headline.   It’s sad that this inherent bias in media reporting ensures the public gets an unhealthy dose of incorrect scientific information and rarely gets the antidote.]

None of this at all diminishes LHCb’s accomplishment!  They’ve made a great measurement, for which they deserve big congratulations.  A round of applause, please!!  But let’s not overstate its immediate impact.  As the measurement becomes more precise, its impact will gradually become greater, and even more so when it is combined with similar measurements from ATLAS and CMS.

But meanwhile, there were powerful and truly new constraints on supersymmetry (and other theories) reported at this conference, and they came from ATLAS and CMS, in their searches for effects from superpartner (and other) particles.  I told you about a small number of these searches a couple of days ago (by the way, I learned meanwhile that CMS has a search that is similar to the one I mentioned from ATLAS  involving bottom quarks) and maybe I’ll point out a few others next week, if I have the energy.

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43 Responses

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  5. You clearly do not understand how errors work, if you think bota resulta from LHCb are not compatible. Also, I believe you should be more clear about your biases towards one experiment. It’s okay to cheer for ATLAS/CMS, it’s not okay to disrespect the work of LHCb physicists.

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  8. Are the different versions of SUSY independent events? If so, then proving 5 versions out of 10 wrong does not affect the probability of the remaining 5 versions. But if they are not independent events, then conditional on 5 versions being ruled out, the probability of the remaining 5 being lower is lower. Is this a good way to consider the “Blow” issue?

  9. Dear ewj9,
    Iam not an expert. I stay with your question, “Could it be that the spin detected on some of the particles, are obliged to spin because they have more energy and the availability of New Space is not produced fast enough and therefore obliged to rotate and or curve back on themselves? – for experts to answer- because…

    In LHC, a component of spin can be increased or decreased with “raising” and “lowering” operators, and the change is always in natural units of 1. (This is just a result of the universe having three spatial dimensions, so if the answer was any different then the universe would look very different!)

    The expansion of space is in reference to 3-D manifold only; that is, the description involves no structures such as extra dimensions or an exterior universe?.

    Why does our universe look the way it does?: http://news.discovery.com/space/why-does-our-universe-have-three-dimensions-120119.html

    1. Thanks again….actually none of us are experts, and we are just recovering with the news that atoms exist in modern science. You mention the spin is adjustable! This is very interesting…… and the change is always in natural units of 1. ?? what does that mean please?

      In a way the universe does look different in 3D when temporal time dilates the faster the clock is moving. We cannot fathom that. It is like light – has have the value of C and clocks operate slower the faster they move. But surely this is an indication of our current inability to understand why? Similarly a few centuries ago the sea would ebb and flo – it was taken for granted ! like light speed and time dilation. Until that is Mr Galileo had an idea. And now we ignore it because it is rather uninteresting.

      “that is, the description involves no structures such as extra dimensions or an exterior universe?”.

      Could I ask you to go further with this comment so I understand better your meaning.

      A fantastic link you provided thanks………in looking at it very briefly sort of satisfies my intuition of 4D. Remove matter and with it you strip away 3D spacetime. And what is left?

      1. If there is a physical situation in which it is impossible to tell which way it happened, it always interferes; it never fails. The word “interferes” in this context is a quick way of saying that such objects fall under the rules of quantum mechanics, in which they behave more like waves that interfere than like everyday large objects.
        A tensor field is a generalization of a scalar field or vector field that assigns, respectively, a scalar or vector to each point of space. For example a vector space of one dimension depending on an angle could look like a Möbius strip as well as a cylinder. Raising and lowering indices: One does this by multiplying by the covariant or contravariant metric tensor and then contracting indices, meaning two indices are set equal and then summing over the repeated indices. One can raise or lower indices to change a type (a, b) tensor to a (a + 1, b − 1) tensor (raise index) or to a (a − 1, b + 1) tensor (lower index), where the notation (a, b) has been used to denote the tensor order a + b with a upper indices and b lower indices.

        By this, one can only measure the total spin because… We can never measure the spin of a particle exactly, and the best we can do is measure its total spin, and its projection along a certain axis. The spin along the other two axes remains a mystery, because as soon as we measure its spin along one axis, the other two components of spin become indeterminate- why?

        Measuring the total spin of fermions and bosons is consistent, but why not with Higgs boson?. If it is 0 spin, there is no decay into other particles to measure the spin?

        All massive particles interact with a universal Higgs field in proportion to their bound energy content, and it is this interaction or “Higgs ether drag” which causes the inertial resistance to acceleration we characterize as mass.
        In this point The Higgs vev is the order parameter for electroweak symmetry breaking. It behave like photon’s electromagnectic field but with mass like “brothers(goldstone bosons) impregnated” W and Z bosons(weak forces).

        Uniting “massless” photons(field) can create rest mass.
        In above case, the rest mass is given by “gold stone bosons” and ” inertial mass” is given by “Higgs boson”. Thus uniting gravitational and electroweak forces?

        The interaction of a massive particle’s gravitational field with the spacetime metric is an interaction with the same spacetime metric that originally established the weak force. So “Higgs boson” intracts and interfers with the metric field of spacetime.
        The forced interaction between these two metric fields, one asymmetric and the other symmetric, also produces the anomalous results of relativistic motion in the spatial, temporal, and mass parameters of the moving or accelerated system- which is not in the case of masless photons or tiny neutrinos which does react with weak foeces but not like “gold stone bosons(brothers)” -Higgs boson bond.

        The spacetime metric didn’t interfere with symmetry breaking of goldstone bosons, but interfers with “spontaneous symmetry breaking” of Higgs boson. So there is a flip in its quantum conservation.

        At the time of big bang, all particles are moving so fast they are essentially the same as photons moving at velocity c. When space expands, further cooled energy level, there are no large, empty dimensions: instead, the metric is densely occupied with particles (quarks and leptons); photons cannot move freely under these conditions in any case. Symmetry is expressed through a “particle metric” rather than a dimensional metric. Symmetry-breaking occurs as these particles are released into the large spacetime dimensions of present space.
        Futher expansion will create more space but dimensions..????

        1. “Higgs boson” intracts and interfers with the metric field of spacetime.

          Very detailed reply – thank you very much for your kind and full response!

          The behavior of the infinitesimal is really beyond me. I could be pulled into the same fray of trying to comprehend it – but I think it drives us all mad – like trying to comprehend the universe. In trying to get to understand the Big Nature. I am aware of the components of the StdM and that protons comprise x2 up and x1 down quark etc. ( the ‘definition’ of matter is the challenge in my mind ) When does it actually become identifiable as matter in the everyday sense)? As the more you look at it the less it appears to be matter at all, just interactive forces between strange little things, which in some instances not only have no mass but also no dimension! So how can we make sense of these tools?

          Your educated reply brings me great value and I don’t want to simply pass it by without considerate attention. However, I can’t help but feel that we are on the wrong track for a New View. Sure, we can continue to research and build larger LHC’s – maybe one in space in the future where it is isolated from the gravity of the earth etc. Has anyone thought about that? We have 200 in a gravity field but none without. We are trying to look at clean particles in the mud of gravity which may well affect the behavior? Maybe that is all we need to do – to put the device into a cleaner environment? And maybe cheaper as it would not have to be underground with all that stainless conduit?

          “Higgs boson” intracts and interfers with the metric field of spacetime”.

          But we don’t even know if we have an HB. It is intuitive speculation – like ‘M’Th Maybe? the HB is actually the background energy of new space being created in the first place ( 1. No space = nothing = not even void, 2. It is produced and the infinitesimals are formed )?

          What happens afterwards is of no interest to nature. E.g. they happen to form proton’s and baryons is of no importance. The primary is to create new space. And when you have solid matter ( ?) then you have 3 dimensions as they actually create it by their presence, even though they maybe dimensionless?

          Now that would be interesting and a new way of actually considering it. It is not an HB at all. Nothing more than the background energy of the (Primary dimension) just creating new space where nothing existed before? Which is being created constantly at the value of C where we live. And as this new space is formed it is obliged to coalesce into infinitesimals which have repeated characteristics, which involve time and force?…

          Maybe we should look at the big picture and not just a small part of it?

  10. Dear Matt – Please comment: If we do in fact cohabit with a Primary dimension of 4D’s. Where the primary is responsible for the production of ‘Primary New Space second for second’ ( of our linear time ). Then the x,y,z is the only bit which is stretching ( the existing historic space where the 3D exists because of the presence of matter in it). So you have 2 things occurring. 1. ‘New space’ being created ( from nowhere but all around us at value C ). and 2. That space whence created is stretching. Can you visualise this scenario?

    Then 3. the historic space ( hubble Z) is dispersing/diluting the objects in it.
    If we then consider the LHC work P New Space is required second for second. Could it be that the spin detected on some of the particles, are obliged to spin because they have more energy and the availability of New Space is not produced fast enough and therefore obliged to rotate and or curve back on themselves? e.g. They are experiencing a torque against time itself? So what we observe and measure is not necessarily a function of what they ‘want to do’ – but what they are physically – ‘obliged to do’!

    1. Dispersing/diluting the objects in it:
      With exponentially expanding space, two nearby observers are separated very quickly; so much so, that the distance between them quickly exceeds the limits of communications. The scalar field slowly relaxes to the vacuum, the cosmological constant goes to zero, and space begins to expand normally.
      The new regions which come into view during the normal expansion phase, in the global point of view, are exactly the same regions which were pushed out of the horizon during inflation, and so they are necessarily at nearly the same temperature and curvature, because they come from the same little patch of space. In the local point of view, the cosmological horizon still is at the big bang, and inflation is always going on in a thin skin where time is nearly stopped, and the same process produces new regions as it always did, up to small fluctuations.

      This prediction means that the total ordinary matter, dark matter, and residual vacuum energy in the universe have to add up to the critical density, a prediction which is very accurately confirmed. More strikingly, inflation allows physicists to calculate the minute differences in temperature of different regions from quantum fluctuations during the inflationary era, and these quantitative predictions have also been confirmed.???

      1. Dear Veeramohan,

        Thanks very much for this. Yes I appreciate much of the established yardstick, although I do need to be reminded to keep me driving on the left and steering wheel on the right.

        However just in passing is Prof Guth’s theory still hold good? Ref the isothermal universe? I understood there is a problem regards Linear time and actual dimension achieved of the universe, or do we just say it was moving faster than light to achieve it?

        Your valued and appreciated refs relate to 3 dimensions where matter ( observable objects exist ). In my thinking if no objects exist then there is no 3D spacetime or any relevance to STR and GTR. What is inflating is the spacetime created by objects in it.

        What is your opinion regards “Want to move or obliged to move”. E.g. a candle flame always burn bright and up. It is in a torque with gravity/air. In the LHC a dispersion of particles are they behaving they want to behave or are they also experiencing a torque? i.e. Time for instance.

        How does one measure ‘anything’ is stretching if one has no reference frames and the temp is isometric? I will look forward to your answer. Remove all the objects – is it still expanding? Or is it just our local spacetime which is expanding because of matter existing in it? – thanks.

  11. Are you sure it makes statistical sense to compare the previous one sided limit with a two sided limit? Not saying it isn’t, but it would be good to have LHCb’s word on it.

  12. Is the Standard Model, really, the Theory of Chaos? … i.e. “parts per billion”
    Can a plane wave get diffracted?
    What is energy?
    Is dark energy the inner volume of the universal shell (soap bubble) we live in?

    what would you say if I said the universe is actually 172 billion years old? … based of the assumption the energy density (eV’s / unit volume) is uniformed across the universe.

  13. Your blog is normally very good, Matt, and I’m normally very happy to link to your pieces.

    But you’ve got to be kidding me. Perfect agreement with Standard Model, with accurate error bars that still allow some wiggle room for SUSY reachable by the LHC, but no evidence for departure from SM. You are clearly hoping for SUSY at the LHC, but a display of healthy skepticism and nuance — like you displayed with the FTL/OPERA neutrinos — would be welcome from you on this issue.

  14. Can you give us a link to Professor Michelangelo Mangano’s summary talk? Non-experts can find these documents quite interesting even if they don’t follow every word or equation. Thanks.

    1. kds.kek.jp/getFile.py/access?contribId=56&sessionId=33&resId=0&materialId=slides&confId=9237

      but not easy without audio/video

  15. /The decay reported in Japan, at a Kyoto gathering of particle physicists, emerged – like the presumed Higgs – from light-speed collisions in the LHC that recreate the primeval disorder that followed the Big Bang some 13.7 billion years ago./– reuters.

    LHC is the greatest engineering marvel of our time.

  16. Matt

    While I agree with you totally on the Pallab Ghosh piece (I did a totally different

    one for Reuters on the same day, which was jigged around a bit by deskers



    I must tell you the BBC did go some way to making amends last night in a Radio IV discussion programme

    which referred to “differing views” on SUSY and then interviewed at length

    LHCb scientist Tara Shears who – without naming him – totally dismantled Ghosh.

    You probably know that folk at CERN banged off protest messages to him on

    Monday and Tuesday, but of course there was no response.

    Keep up the great work. Vital to dabblers like me trying to write up a subject

    we only marginally understand for the wider public (and uncomprehending but

    know-better editors).



  17. According to the LHCb preprint (arXiv:1211.2674) they have tightened the upper limit on the related B^0 decay, very slightly, from 1.0 per billion to 0.94 per billion. But (in terms of constraints on SUSY models) presumably this doesn’t outweigh the loosening of the upper limit on B_s^0?

  18. Matt, but some SUSY models are more likely than others, right?

    This is what the public need to know: Are the most likely SUSY models being eliminated right now, leaving the less likely ones, and therefore putting SUSY in hospital?

    Or are the most likely SUSY models distributed fairly evenly throughout the parameter space?

    1. How do you want to determine what is “likely” from nature’s point of view? Can such an a priory probability distribution, giving the probability that nature has choosen it for each point in the parameter space, be determined before we have found out how nature really works ? Or is everything we can do just state our human preferences and prejudices?

      You are obviously sure that it can be done, so I’d like to know why and how ?

      1. @Dilaton with respect, this question was addressed to Matt, so please don’t hijack it unless you can answer it. Thanks 🙂

      2. @dopey_john
        With respect, if I have some related questions I have the right to ask them too below the post they are related to.
        If Prof. Strassler finds time to come back here, he can answer all of them if he wants to 🙂

        But I can understand that you prefer, as you said earlier, scornful, dishonest, and unfair bloggers (who try hard to negatively influence science and undermine the natural scientific process) to come here in order to badly insult Prof. Strassler and his colleagues, than seing me asking questions ;-).

        My reason for coming here is to learn physics from this great site, to defend science and Prof. Strassler who is a very clear headed, reasonable, honest, and great scientist, if he and his colleagues (or their great work) get insulted and attacked by the above mentioned blogger and his fans.


      3. BTW my guess or answer to the question is, that it is not a meaningful question since such an a priory probability, which one would need to answer this question, can not be determined since nobody knows how nature chooses the laws of nature she wants to use (with or without SUSY, if with in what particular realization etc)

        But I would be happy if I’m told wrong and can learn better from an answer of Prof. Strassler or somebody else. That is what my above questions are there for 🙂

  19. If you’ve taught me one thing it’s to take what’s reported in the MSM with a grain of salt and wait for the experts to weigh in.

    Thanks for the update.

    1. I fully agree, this is a very nice and interesting update 🙂
      And everybody should learn about it !

      At least the scornful blogger, who always and unnecessarily puts his long nose in here, has obviously seen it too as one can see from his newest pingback 😀


      1. Nothing to add on substance to the several blog entiries and the theron comments you LM and some others have made. I do want to join in thanking Professor Strassler for his thorough and balanced posts and the hard work he puts onto this site.

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