Sabine Hossenfelder (see
this) told that 4.8 sigma evidence for B meson anomaly manifesting itself in the decays of B meson to K
* meson plus muon pair has been reported (see
this).
1. What is known?
Below is the abstract of the article telling about the finding.
An analysis of the decay amplitudes of B0; K*0→ K+π -μ +μ - is presented, using proton-proton collision data recorded by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 8.4 fb-1. The amplitudes are constructed from Legendre polynomials in the μ+μ+ invariant mass squared region 1.1 < q2< 8.0 GeV2/c4. CP-averaged observables are obtained from the amplitudes.
Some of these observables present deviations with respect to the Standard Model, which can be interpreted as shifts in the effective Wilson coefficients. This model-independent approach enables tests of theoretical predictions that can help disentangle hadronic effects from potential contributions from physics beyond the Standard Model. This allows flexibility in the choice of q2 binning for global analyses. Depending on the binning scheme, the deviation of the Wilson coefficient C9 from its Standard Model expectation varies from 4.3σ to 4.8σ.
A large variety of models explaining the B meson anomaly have been proposed. Perhaps the simplest model for the anomaly is in terms of a heavier partner Z' of Z0 boson.
The anomaly reduces to that associated with the vertex involving a transformation of the b quark to s quark by CKM mixing by the emission of Z' boson.
Since a very short distance phenomenon is in question this can be approximately described in effective QFT approach by a purely local interaction terms as product of the neutral weak current involving b and s quark and muon pair. This description is completely analogous to the description of weak interactions in terms of the four-fermion vertex in the original Fermi model.
As in the Fermi model, the interaction term is space-time integral for the product of weak currents involving Z' propagator proportional to the inverse mass squared of Z' having spatial dimension 2. The spatial dimension of the product of weak fermion currents coefficient of is determined by d=-6. In the parameterization the mass squared gives a proportionality constant proportional to cutoff mass squared 1/μ 2. The index of C9 is a convention for labelling various non-local interaction terms of the effective action of the standard model. There is no perturbative expansion since effective action is in question and the interaction term gives a simplified description for the loops responsible for the appearance of heavier particles in the interaction vertex making possible the anomaly.
Google Gemini informs that there are two kinds of models possibly explaining the anomaly in terms of Z'. If the Z' gauge coupling is comparable to the Standard Model electroweak couplings gZ' ∼ 0.1 - 1.0, global fits to the b → l+l- data typically restrict its mass to the range (1-7) TeV. Why this range?
- The lower bound is ∼ 1-2 TeV: direct searches at ATLAS and CMS rule out lighter Z' bosons. If Z' were lighter than this and coupled directly to muons, it would have already appeared as a striking resonant "peak" in dimuon μ+μ- invariant mass distributions at the LHC.
- The Upper Bound ∼ 5-7 TeV: If the mass is any higher, its effect on the low-energy Wilson coefficients C9 would become too weak to explain the observed deviations in B-meson decays, unless the couplings are artificially dialed up to mathematically unstable levels.
If the couplings are allowed to be much larger (approaching the perturbative limit where quantum field theory calculations remain reliable), the Z
' can hide at much higher energy scales: M
Z' ∼ 10-30 TeV
In this scenario, a heavy Z
' is too massive to be directly produced at the LHC, but its virtual "ghost" signature would still be heavy enough to generate the required modifications to the Wilson coefficients. Testing a Z
' in this range requires future facilities like the Future Circular Collider (FCC) or a high-energy muon collider.
2. What could TGD say about the B anomaly?
TGD predicts a hierarchy of scale up copies of the standard model physics. p-Adic length scale hypothesis involves the conjecture is that these copies are labelled by 3 kinds of Mersenne primes: ordinary Mersenne primes Mk =2k-1, Gaussian Mersennes MG,k =(1+i)k-1 and Eisensteinian Mersenne primes (see this). Ordinary hadron physics correspond to M107 =2107-1, there is evidence for M89 hadron physics, which would be the scaled up version of ordinary hadron physics with 512 times higher mass scale and also for the MG,79 hadron physics with mass scale higher by a factor 214. The next candidate would be M61 hadron physics with mass scale higher by factor 223. Therefore MG,79 remains the only option.
Ordinary weak bosons correspond to M89 and this would mean that for MG,79 weak physics, the mass scales of weak bosons are by a factor 32 higher than for the standard model weak interactions. For the scaled up version of the ordinary Z0 boson with mass .09 TeV this would predict a mass M= 2.88 TeV. This mass belongs to the region allowed by coupling strength which are of same scale as for the standard model.
2.1 What guesses can one make about the new bosons possibly explaining the B anomaly?
- Google Gemini informs that if the couplings are in the range .1-1 for weak couplings needed for perturbation theory the mass of the new boson is in the range 1-5 TeV. There is an estimate of 2.9 TeV for the mass of the new boson.
- TGD predicts a hierarchy of standard model physics. Weak interactions correspond to the p-adic scale associated with the Mersenne prime M89. The next p-adic length scale corresponds to MG,79. The scaling Z0 mass from M89 to MG,79 by factor 32= 2(89-79)/2 gives mass of 2.88 TeV, which is rather near to the empirical estimate. MG,79 is the only possibility since the next candidate M61 would give a huge mass.
- For this option the universality of quark and lepton couplings is the first guess. There are however indications for the violation of fermion universality and TGD allows us to consider a model explaining these violations (see this and this).
2.2. What could happen in the transformation of b quark to s quark?
Consider first what might happen the creation of a muon pair as b quark transforms to s quark.
- The decay of B meson to muon pair or to K* and muon pair induced by the transformation of b quark to s quark. The direct coupling b → s vanishes. Since neutral-current couplings are diagonal. CKM mixing for charged-current couplings involving the emission of a virtual W boson makes possible the b-s coupling via radiative corrections. Therefore a radiative correction involving emission of virtual W bosons must be involved.
- Upon the emission of a W boson, the b quark temporarily transforms into a c, u, or t quark. This W boson is then absorbed and i by CKM mixing gives rise to say s quark. The virtual W boson emits an MG,79 photon (γ79) or Z0 boson Z79, which subsequently decays into, say, a muon pair. This gives a small correction to the production rate predicted by the standard model.
With this in mind, we can re-examine the situation from the TGD perspective.
- The standard view remains valid, but in the context of M89 hadron physics, the "official" t quark would naturally correspond to the M89 u quark. The t quark is replaced by the "Aleph" quark, which has a mass of 56 GeV (see this, this and this). If the coupling to the official t quark is small, Aleph quark dominates, and the mass squared scaling reduces the amplitude by a factor of (56/175)2 ∼ 1/9. This constitutes a fundamental prediction that is easily ruled out. The propagator of ZG,79 would give a reduction factor 1/M2ZG,79. The re-identification of t quark changes the CKM matrix and this affects the coupling.
- What about evidence for the violation of universality - a phenomenon for which some evidence exists and about which I have previously written (see this and this )? Could the Z and W bosons be states in which different genera carry different weights. In the case of γG,79 genus-dependent weights look problematic since the em charges of different fermion generation would be apparently different. This is because in the TGD based model the mesons are regarded as superpositions of fermion pairs associated with different generations.
2.3 Could the MG,79 weak physics emerge in a phase transition M89→ MG,79?
This would alter the coupling of the Z boson within the W loop and also the coupling of W. Could all electroweak bosons be dark MG,79 bosons this would be visible in the mass dependence of the loops.
What happens in the transition between different standard model copies is an interesting problem. I suspect that a phase transition rather than mixing is in question. One can take the phase transition from M107 to M89 as a role model. The transition would take place quantum criticality generating a dark M89 phase with heff scaled up by 512. One can imagine at least two options but the following first one looks the most plausible.
- Quantum criticality would be lost in p-adic cooling \cite{allb/tgdnewphys1} (see this and this). The most recent application is to the TGD counterpart of energy production in the Sun that would occur at the surface of the Sun (see this).
The p-adic mass scale would be reduced step by step, most naturally by octaves or half-octaves and decay to "virtual hadrons" characterized by this scale would take place. The value of heff would also reduce gradually so that the Compton lengths would not be affected. The process would be analogous to overheating followed by cooling without a dramatic compression.
- Second option that one can imagine is that first quantum criticality would be lost completely by a reduction of M107 p-adic length scale to M89 p-adic length scale, meaning a contraction by factor 1/512. After that explosive increase of the p-adic length scale by stepwise manner down to M107 would take place.
Similar picture should apply to the transition for M
89 electroweak physics to its M
G,79 variant.
- The emission of a Z79 or γ79 by virtual W boson with a mass of 2.88 TeV would result in the production of muon pairs. The decay to muon pairs correspond to final-state interactions; for the purpose of predictions, only the process leading to the emission of
Z79 or γ79 is relevant.
- The estimate for the mass of the emitted particle comes from the propagator of the new particle. The mass of Z would be too small. Z79 propagator with much larger mass would add to the additional small contribution of the ordinary Z. The additional contribution to the amplitude is proportional to m2(t)/m2(Z79).
If t quark is the "official" t quark, the M2t/M2>ZG,79 = (0.175/2.88)2 = 3.7 × 10-3 provides the scale factor. If the official top quark is replaced by an "Aleph" quark (see this), an additional factor of 1/9 approximately equal to the mass squared ratio of Aleph quark and top quark emerges and gives a factor 4× 10-4.
- What about the propagator of γ79 if it has a very small mass (this is if p-adic mass calculations contribute to its mass only in the second order). If ZG,79 is nearly on mass- shell, its contribution is larger than that of γG,79.
Acknowledegements: I want to thank Martin Ebner and Marko Manninen for spontaneous AI assisted help in the analysis of the B anomaly.
For a summary of earlier postings see Latest progress in TGD.
For the lists of articles (most of them published in journals founded by Huping Hu) and books about TGD see this.