Modern Physics Letters A

The covariant density matrix formalism is used to obtain the joint angular distributions of the decay B → V₁V₂ followed by subsequent decays V₁ → a₁b₁ and V₂ → a₂b₂. In particular, the case that V₁ is J/ψ and V₂ is an axial vector meson K₁(1270) as well as a vector meson like K*(890) or ϕ(1020) is considered and also the decay mode of ϕ → ρ π besides ϕ → K⁺ K^- is discussed.

The current status of solar neutrino measurements and their oscillation interpretation is reviewed.

Top-down models for the origin of ultra high energy cosmic rays (UHECR's) propose that these events are the decay products of relic superheavy metastable particles, usually called X particles. These particles can be produced in the reheating period following the inflationary epoch of the early Universe. We obtain constraints on some parameters such as the lifetime and direct couplings of the X-particle to the inflaton field from the requirement that they are responsible for the observed UHECR flux.

We describe how to reduce the fuzzy four-sphere algebra to a set of four independent raising and lowering oscillator operators. In terms of them we derive the projector valued operators for the fuzzy four-sphere, which are the global definition of k-instanton connections over this noncommutative base manifold.

In this paper we propose a superfield description for all Bianchi-type cosmological models. The action is invariant under world-line local n = 4 supersymmetry with SU(2)_local ⊗ SU(2)_global internal symmetry. Due to the invariance of the action we obtain the constraints, which form a closed superalgebra of the n = 4 supersymmetric quantum mechanics. This procedure provides the inclusion of supermatter in a systematic way.

The quantum entropies of the black hole, due to the massless Klein–Gordon and Dirac fields, are investigated by Rindler approximation. The difference from the brick wall model is that we take into account the effect of the generalized uncertainty relation on the state counting. The divergence appearing in the brick wall model is removed and the entropies proportional to the horizon area come from the contributions of the modes in the vicinity of the horizon. Here we take the units G=c=ℏ=k_B=1.

We consider all possible scalar bilinears, which couple to two fermions of the standard model. The various baryon and lepton number violating couplings allowed by these exotic scalars are studied. We then discuss which are constrained by limits on proton decay (to a lepton and a meson as well as to three leptons), neutron–antineutron oscillations, and neutrinoless double beta decay.