Monday, September 07, 2015

First indications for the breaking of lepton universality due to the higher weak boson generations

Lepton and quark universality of weak interactions is basic tenet of the standard model. Now the first indications for the breaking of this symmetry have been found.

  1. Lubos tells that LHCb has released a preprint with title Measurement of the ratio of branching ratios (Bbar0→ Dbar *+ τ ντ)/ (Bbar0→ Dbar*+ μ νμ). The news is that the measured branching ratio is is about 33 per cent instead of 25 percent determined by mass ratios if standard model is correct. The outcome differs by 2.1 standard deviations from the prediction so that it might be a statistical fluke.

  2. There are also indications for second Bbar0 anomaly (see this). B mesons have to long and short-lived variants oscillating to their antiparticles and back - this relates to CP breaking. The surprise is that the second B meson - I could not figure out was it short- or long-lived - prefers to decay to eν instead of μnu;.

  3. There are also indications for the breaking of universality (see this) from B+ → K+e+ e- and B+ → K+ μ+mu;- decays.

In TGD framework my first - and wrong - guess for an explanation was CKM mixing for leptons. TGD predicts that also leptons should suffer CKM mixing induced by the different mixings of topologies of the partonic 2-surfaces assignable to charged and neutral leptons. The experimental result would give valuable information about the values of leptonic CKM matrix. What new this brings is that the decays of W bosons to lepton pairs involve the mixing matrix and CKM matrix whose deviation from unit matrix brings effects anomalous in standard model framework.

The origin of the mixing would be topological - usually it is postulated in completely ad hoc manner for fermion fields. Particles correspond to partonic 2-surfaces- actually several of them but in the case of fermions the standard model quantum numbers can be assigned to one of the partonic surfaces so that its topology becomes especially relevant. The topology of this partonic 2- surface at the end of causal diamond (CD) is characterized by its genus - the number of handles attached to sphere - and by its conformal equivalene class characterized by conformal moduli.

Electron and its muon correspond to spherical topology before mixing, muon and its neutrino to torus before mixing etc. Leptons are modelled assuming conformal invariance meaning that the leptons have wave functions - elementary particle vacuum functionals - in the moduli space of conformal equivalence classes known as Teichmueller space.

Contrary to the naive expection mixing alone does not explain the experimental finding. Taking into account mass corrections, the rates should be same to different charged leptons since neutrinos are not identified. That mixing does not have any implications follows from the unitary of the CKM matrix.

The next trial is based on the prediction of 3 generations of weak bosons suggested by TGD.

  1. TGD based explanation of family replication phenomenon in terms of genus-generation correspondence forces to ask whether gauge bosons identifiable as pairs of fermion and antifermion at opposite throats of wormhole contact could have bosonic counterpart for family replication. Dynamical SU(3) assignable to three lowest fermion generations/genera labelled by the genus of partonic 2-surface (wormhole throat) means that fermions are combinatorially SU(3) triplets. Could 2.9 TeV state - if it would exist - correspond to this kind of state in the tensor product of triplet and antitriplet? The mass of the state should depend besides p-adic mass scale also on the structure of SU(3) state so that the mass would be different. This difference should be very small.

  2. Dynamical SU(3) could be broken so that wormhole contacts with different genera for the throats would be more massive than those with the same genera. This would give SU(3) singlet and two neutral states, which are analogs of η′ and η and π0 in Gell-Mann's quark model. The masses of the analogs of η and π0 and the the analog of η′, which I have identified as standard weak boson would have different masses. But how large is the mass difference?

  3. These 3 states are expected to have identical mass for the same p-adic mass scale, if the mass comes mostly from the analog of hadronic string tension assignable to magnetic flux tube. connecting the two wormhole contacts associates with any elementary particle in TGD framework (this is forced by the condition that the flux tube carrying monopole flux is closed and makes a very flattened square shaped structure with the long sides of the square at different space-time sheets). p-Adic thermodynamics would give a very small contribution genus dependent contribution to mass if p-adic temperature is T=1/2 as one must assume for gauge bosons (T=1 for fermions). Hence 2.95 TeV state for which there are some indications could indeed correspond to second Z generation. W should have
    similar state at 2.5 TeV.
The orthogonality of the 3 weak bosons implies that their charge matrices are orthogonal. As a consequence, the higher generations of weak bosons do not have universal couplings to leptons and quarks. The breaking of universality implies a small breaking of universality in weak decays of hadrons due to the presence of virtual MG,79 boson decaying to lepton pair. These anomalies should be seen both in the weak decays of hadrons producing Lν pairs via the decay of virtual W or its partner WG,79 and via the decay of virtual Z or its partner Zg,79 to L+ L-. Also γG,79 could be involved.

This could explain the three anomalies associated with the neutral B mesons, which are analogs of neutral K mesons having long- and short-lived variants.

  1. The two anomalies involving W bosons could be understood if some fraction of decays takes place via the decay b→ c+WG,79 followed by WG,79→ L+ν. The charge matrix of WG,79 is not universal and CP breaking is involved. Hence one could have interference effects, which increase the branching fraction to τν or eν relative to μν depending on whether the state is long- or short-lived B meson.

  2. The anomaly in decays producing charged lepton pairs in decayse of B+ does not involve
    CP breaking and would be due to the non-universality of ZG,79 charge matrix.
TGD allows also to consider leptoquarks as pairs of leptons and quarks and there is some evidence for them too! I wrote a blog posting about this too (for an article see this). Also indications for M89 and MG,79 hadron physics with scaled up mass scales are accumulating and QCD is shifting to the verge of revolution (see this).

It seems that TGD is really there and nothing can prevent it showing up. I predict that next decades in physics will be a New Golden Age of both experimental and theoretical physics. I am eagerly and impatiently waiting that theoretical colleagues finally wake up from their 40 year long sleep and CERN will again be full of working physicists also during weekends (see this);-).

See the chapter New Particle Physics Predicted by TGD: Part I of "p-Adic Length Scale Hypothesis".

For a summary of earlier postings see Links to the latest progress in TGD.

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