Ytterbium anomaly

Sabine Hossenfelder talked about a very interesting nuclear physics anomaly known as Ytterbium anomaly (see this). There is a Phys. Rev. Lett. article about this anomaly titled "Probing New Bosons and Nuclear Structures with Ytterbium Isotope Shifts" (see this). What makes this anomaly so interesting is that it is reported to have a significance level of 23 sigmas! 5 sigmas is usually regarded as the significance, which makes it possible to speak of a discovery.

1. Ytterbium (see this) is a heavy nuclear with charge Z=70 and mass number of A=173 so that neutron number would be N= 103 for the most general isotope (it seems that the definition of isotope number varies depending on whether its defined in terms of mass or the actual number of nucleons). The mass numbers of Yb vary in the range 168-176. Ytterbium is a rare earth metal with electron configuration [Xe] 4f¹⁴6s^2.
2. The electronic state seems to be very sensitive to the number of neurons in Yb and this is why Yb is so interesting from the point of view of atomic physics. The anomaly is related to the isotope shift for the electron energies. So called Frequency Comb method amplifies the mismatch with the standard theory. Mismatch indeed exists and could be understood in terms of a new particle with a mass of few MeVs.
3. There is an earlier anomaly known as Atomki anomaly (see this and this) explained by what is called X boson in mass range 16-17 meV and the Yb anomaly could be explained in terms of X boson (see this).

I have discussed the X boson in the TGD framework and proposed that it could be a pion-like state (see this).

1. The proposed model provides new insights on the relation between weak and strong interactions. One can pose several questions. Could X could be a scaled variant of pion? Or could weak interaction physics have a scaled down copy in nuclear scale?
2. The latter option would mean that some weak boson could become dark and its Compton length would be scaled up by factor h_eff/h to nuclear p-adic length scale. I have proposed a scaled up copy of hadron physics characterized by Mersenne prime M₈₉ with a mass scale, which is 512 higher than for ordinary hadrons with M₁₀₇. In the high energy nuclear collisions in which quark-gluon plasma is believed to be created at quantum criticality, M₈₉ hadrons would be generated. They would be dark and have h_eff/h=512 so that the scaled up hadronic Compton length would be the same as for ordinary hadrons (see this and this). M₈₉ hadron physics would explain a large number of particle physics anomalies and there is considerable evidence for it. The most radical implications of M₈₉ hadron physics would be for solar physics (see this).

Could also weak interaction physics have dark variants at some kind of quantum criticality and could the Yb anomaly and Atomki anomaly be understood as manifestations of this new physics.

1. Weak bosons are characterized by p∼ 2^k, k=91, from the mass scale of weak bosons. A little confession: for a long time I believed that the p-adic mass scale of weak bosons corresponds to k=89 rather than k=91. For the Higgs boson the mass scale would correspond to M₈₉. TGD also predicts a pseudoscalar variant π_W of the Higgs boson. Could the dark variant of the pseudoscalar Higgs boson π_W with Compton length assignable to the X boson be involved?
2. The scaled up weak boson should have a p-adic length scale which equals nuclear length scale or is longer. Dark π_W could become effectively massless below its Compton length. The mass of X boson about 16-17 MeV corresponds to a Compton length of 6× 10^-14 m and is by factor 3 longer than the nuclear p-adic length scale L(k=113)∼ 2× 10^-14 m. For k_πW=91 would give h_eff/h= 2^(113-91)/2=2¹¹ to give the nuclear Compton scale. k=115 would give the length scale 4× 10^-14 m not far from 6× 10^-14 m and require h_eff/h= 2^(115-91)/2=2¹². If π_W corresponds to k=89 then h_eff/h= 2^(115-89)/2=2¹³.

   If the π_W Compton scale is scaled from M₉₁ by factor 2^(113-89)/2=2¹² to a Compton length corresponding for ordinary Planck constant to the mass of about m_πW/2¹². This would give m_πW∼ 64 GeV, essentially one half of the mass of the ordinary Higgs about 125.35 GeV and corresponds to the p-adic length scale k=91 just like other weak bosons.

3. Could dark π_W give rise to a dark weak force between electron and nucleus inducing the anomalous isotope shift to electron energies? The increase of the Compton length would suggest the scaling up of the electron nucleus weak interaction geometric cross section by the ratio (m_X/m_W)⁴ ∼ 10²⁰? The weak cross section for dark π_W have the same order of magnitude than nuclear strong interaction cross sections since, apart from numerical factors depending on the incoming four-momenta, the weak cross section for electron-nucleon scattering goes like G_F∼ 1/TeV². This would scale up to 2^113-91=22/TeV²= 4/MeV² (see this). The alternative manner to understand the enhancement could be by assuming that weak bosons are massless below the nuclear scale.
4. Quantum criticality would be essential for the generation of dark phases and long range quantum fluctuations about which the emergence of scaled up dark weak bosons would be an example. Yb is indeed a critical system in the sense that the isotope shift effects are large: this is one reason for why it is so interesting. Why would the quantum criticality of some Yb isotopes induce the generation of dark weak bosons?

It should be noticed that for k=512 assigned with dark M₈₉ hadrons, the scaled down Compton length of dark π_W would be by a factor 8 shorter and correspond to mass 128 MeV not far from the pion mass. What could this mean? Could ordinary pion correspond to a dark dark variant of π_W? This looks strange since usually strong and weak interactions are regarded as completely separate although the CVC and PCAC suggest that they are closely related. In TGD, the notion of induced gauge field implies extremely tight connections between strong and weak interactions.

See the article X boson as evidence for nuclear string model or the chapter Nuclear string hypothesis.

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.