Thursday, December 10, 2015

research level - What is the most natural new physics one can expect at the TeV scale: new (supersymmetric)particles or some new (non-commutative) spacetime structure?


Up to now, nothing else than one Standard Model (SM) Higgs boson-like resonance has been found at the LHC while many predictions based on effective theories using supersymmetry require several Higgs scalars and needs an entourage of sparticles close in mass to tame its quantum instabilities (I borrow more or less from James D. Wells).


On the other hand, the spectral and almost-commutative extension of the SM by Chamseddine and Connes, expects only one Higgs boson without other particles in the TeV range. In this noncommutative approach spacetime appears as the product (in the sense of fibre bundles) of a continuous manifold by a discrete space and it has been proved by Martinetti and Wulkenhaar that under precise conditions, the metric aspect of ”continuum × discrete” spaces reduces to the simple picture of two copies of the manifold.


Could it be that this picture of a two-sheets spacetime helps to overcome the technical naturalness issue related to the standard model Higgs (replacing temptatively a low energy supersymmetry by a new geometric framework) and has to be taken seriously in order to progress in the understanding of physics beyond the SM?


To ask it differently:


Reminding that the Standard model like Higgs boson is a natural consequence of the noncommutative geometric framework, could it be that the discreteness of space-time usually expected at the Planck scale from quantum gravity already shows up at the electroweak scale through the very existence of the already discovered Higgs boson? (this formulation could require a new, yet to be defined, heuristic meaning for the term: naturalness)



Last but not least, it is worth noting that to postdict the correct mass of the Higgs boson detected at LHC8, the last version of the spectral model relies on a weak coupling with another scalar that shows up "naturally" in the spectral action just like the Higgs. This "big brother" from the Higgs boson is expected to acquire a vev generating a mass scale above $10^{11}GeV$ for right-handed Majorana neutrinos. It could thus be responsible for a type I see-saw mechanism explaining the neutrino phenomenology beyond the minimal SM.


May be noncommutative geometry can help to make effective theories more alive and kicking! In memoriam Ken Wilson


To celebrate the 4th of July "IndependentHiggsday", I wish a happy birthday to the lightest scalar field of the Standard Model and I congratulate experimentalists who work hard to prove physics is alive (and not ordered by theories ;-)!


EDIT : The title of the question has been changed in an attempt to improve clarity (after reading The Higgs: so simple yet so unnatural); the former title was:



Doubling the number of elementary particles or "doubling space-time" to accommodate Higgs boson phenomenology at 8TeV?





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