Modern Physics Letters A

Recently an event of the decay has been reported. In this letter we have computed the rate for this decay in the heavy quark effective theory with the additional assumption of factorization.

The present apparent cosmological constant is interpreted as the potential of the lightest pseudo-Goldstone boson. Some numerical relations among cosmological parameters and particle masses are shown to arise from the mixture of this very light particle, whose interaction is of the gravitational order, with other pseudo-Goldstone bosons like the pion and the axion which feel the strong interaction.

We suggest a law for the decay of the effective cosmological constant of the form . It is shown that this provides more room for consistency with the recent observational data on Hubble's constant and the age of the universe.

The Weyl correspondence and Wigner operator theory for two-mode correlated system is developed on the common eigenstate basis <η| of two particles' total momentum and relative position. The development brings much convenience for calculating the Wigner functions of some two-mode correlated states and makes some Weyl correspondence derivation possible. Correspondingly, the path integral with midpoint prescription in <η| representation is also formulated.

By describing a large class of deep inelastic processes with standard parametrization for the different parton species, we check the characteristic relationship dictated by Pauli principle: broader shapes for higher first moments. Indeed, the ratios between the second and the first moments and the one between the third and the second moments for the valence partons is an increasing function of the first moment and agrees quantitatively with the values found with Fermi–Dirac distributions.

It is shown that the effects on charmonium production of the modification of nucleon parton distributions inside nuclei are similar in the factorization approach based on nonrelativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total J/ψ production is performed. It is found that a clear x_F dependence of these contributions which, together with an overall normalization given by absorption of the pre-resonant state inside the nuclear medium, can reproduce experimental data a for moderate x_F. However, at large x_F, there is bigger suppression that cannot be fit by this overall normalization together with the shadowing of structure functions.

We find that the local character of field theory requires the parity degree of freedom of the fields to be considered as an additional discrete fifth dimension which is an artifact emerging due to the local description of space–time. Higgs field can be interpreted as the gauge field corresponding to this discrete dimension. Hence the noncommutative geometric derivation of the standard model follows as a manifestation of the local description of the usual space–time.

We study a formulation of Euclidean general relativity in which the dynamical variables are given by a sequence of real numbers λ_n, representing the eigenvalues of the Dirac operator on the curved space–time. These quantities are diffeomorphism-invariant functions of the metric and they form an infinite set of "physical observables" for general relativity. Recent work of Connes and Chamseddine suggests that they can be taken as natural variables for an invariant description of the dynamics of gravity. We compute the Poisson brackets of the λ_n's, and find that these can be expressed in terms of the propagator of the linearized Einstein equations and the energy-momentum of the eigenspinors. We show that the eigenspinors' energy-momentum is the Jacobian matrix of the change of coordinates from the metric to the λ_n's. We study a variant of the Connes–Chamseddine spectral action which eliminates a disturbing large cosmological term. We analyze the corresponding equations of motion and find that these are solved if the energy momenta of the eigenspinors scale linearly with the mass. Surprisingly, this scaling law codes Einstein's equations. Finally we study the coupling to a physical fermion field.