Modern Physics Letters A

This is a brief review of spectroscopic studies of neutrino-less double beta decays (0νββ) and the MOON (Mo Observatory Of Neutrinos) project. It aims at studying the Majorana nature of neutrinos and the mass spectrum by spectroscopic studies of 0νββ with ν-mass sensitivity of 〈m_ν〉 ≈ 30 meV. The solid scintillator option of the MOON detector is a super ensemble of multi-layer modules, each being composed by a scintillator plate and two tracking detector planes. Thin ββ source films are interleaved between the detector planes. High localization of the two β tracks enables one to select true signals and reject BG ones by spatial and time correlation analyses. MOON with detector ≠ ββ source is used for studying 0νββ decays from ¹⁰⁰Mo, ⁸²Se and other ββ isotopes with large nuclear sensitivity (large Q_ββ). Real-time exclusive measurements of low energy solar neutrinos can also be made by observing inverse β rays from solar-ν captures of ¹⁰⁰Mo in delayed coincidence with the subsequent β decay of ¹⁰⁰Tc.

We show that a Green function solution can be given for a class of nonhomogeneous nonlinear systems having relevance in quantum field theory. This in turn means that a quantum field theory in the strong coupling limit can be formulated and the spectrum obtained.

It has been taken as granted that the observation of two independent mass-squared differences necessarily fixes the number of underlying mass eigenstates as three, and that the addition of a sterile neutrino provides an additional mass-squared difference. The purpose of this letter is to argue that if one considers a sterile neutrino component that belongs to the CP² = -𝟙 sector, then both of the stated claims are false. We also outline how the results reported here, when combined with the forthcoming MiniBooNE data and other experiments, can help settle the issue of the CP properties of the sterile neutrino; if such a component does indeed exist.

We investigate higher rank Killing–Yano tensors showing that third rank Killing–Yano tensors are not always trivial objects being possible to construct irreducible Killing tensors from them. We give as an example the Kimura IIC metric from two-rank Killing–Yano tensors to obtain a reducible Killing tensor and from third-rank Killing–Yano tensors, we obtain three Killing tensors, one reducible and two irreducible.

We consider the effect of new physics on the branching ratio of B_s → l⁺l^-γ where l = e, μ. If the new physics is of the form scalar/pseudoscalar, then it makes no contribution to B_s → l⁺l^-γ, unlike in the case of B_s → l⁺l^-, where it can potentially make a very large contribution. If the new physics is in the form of vector/axial-vector operators, then the present data on B → (K, K*) l⁺l^- does not allow a large enhancement for B(B_s → l⁺l^- γ). If the new physics is in the form of tensor/pseudotensor operators, then the data on B → (K, K*) l⁺l^- gives no useful constraint but the data on B → K* γ does. Here again, a large enhancement of B(B_s → l⁺l^-γ), much beyond the Standard Model expectation, is not possible. Hence, we conclude that the present data on b → s transitions allow a large boost in B(B_s → l⁺l^-) but not in B(B_s → l⁺l^-γ).

Since the very beginning of it, perhaps the subtlest of all gauges is the light-cone gauge, for its implementation leads to characteristic singularities that require some kind of special prescription to handle them in a proper and consistent manner. The best known of these prescriptions is the Mandelstam–Leibbrandt one. In this work we revisit it showing that its status as a mere prescription is not appropriate but rather that its origin can be traced back to fundamental physical properties such as causality and covariantization methods.

Assuming the existence of one light sterile neutrino, we investigate the neutrino flavor mixing matrix in matter. Sum rules between the mixing parameters in vacuum and their counterparts in matter are derived. By using these new sum rules, we obtain the simple but exact expressions of the effective flavor mixing matrix in matter in terms of neutrino masses and the mixing parameters in vacuum. The rephasing invariants, sides of unitarity quadrangles and oscillation probabilities in matter are also achieved. Our model-independent results will be very helpful for analyzing flavor mixing and CP violation in the future long-baseline neutrino oscillation experiments.

In this paper, we identify the deeper structure that produces shape invariance. We show that shape invariance appears when a quantum mechanical model is invariant under a centrally extended superalgebra. Also we show that in Φ⁴ and sine–Gordon theories, shape invariance arises from the Bogomol'nyi–Prasad–Sommerfeld (BPS) structure associated with shift operator. The shift operator in two models ensures that there is a one-to-one correspondence between the energy levels and energies of the BPS saturating.