Modern Physics Letters A

The world's data on radio pulsars are not expected to represent the underlying pulsar population because of a search bias against detection of short periods, especially below 1 ms. Yet pulsars in increasing numbers with periods right down to this limit have been discovered, suggesting that there may be even shorter ones. If pulsars with periods below 1/2 ms were found, the conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would be almost inescapable. The plausible ground state in that event is the deconfined phase of (3-flavor) strange-quark-matter. From the QCD energy scale this is as likely a ground state as the confined phase. We show that strange matter as the ground state is not ruled out by any known fact, and most especially not by the fact that the universe is in the confined phase.

We obtain the consistency condition on a U(1) gauge boson mass in a charged closed universe, m² = 8πGJ⁰J₀/(R – 2Λ), where J⁰ is the charge density.

On higher genus Riemann surfaces we define a primary field for affine algebra and vacuum with the use of the prescription by global operator formalism proposed by Krichever and Novikov. From the analytic viewpoint, the Ward-Takahashi identity for current insertion and a partial differential equation for correlators of primary fields are derived.

In this note we briefly discuss the connections of W-algebras with the local characteristic integrals of the generalized Toda lattices, with the Poisson brackets of hydrodynamic type, as well as the supersymmetric extensions of these algebras and their generalizations associated with non-Abelian Toda systems.

The general quantum theory of nonrelativistic, infinitely long straight strings of one flavor interacting via a three-body infinitesimal range potential is considered in (2 + 1) dimensions. It is proved that the tetrahedron equation of Zamolodchikov is satisfied only when the potential is either zero or infinitely repulsive. Therefore the Bethe ansatz is valid only for these special cases.

We consider an extension of the electroweak gauge interactions from SU(2)_L × U(1)_Y to SU(2)_L × U(1)_L × U(1)_R. This extension is motivated by the observed structure of the quarks and leptons, i.e., they form left-handed doublets and right-handed singlets eigenstates of electroweak interactions. In this new extension, the U(1)_R serves only the right-handed singlet fermions. Consistent with the measurements of the mass of the standard massive neutral boson Z⁰ at the SLAC and CERN colliders and the neutral current couplings involving neutrinos and electrons, the additional massive neutral gauge boson can be as light as a few hundred GeV. The model employs the generalized see-saw mechanism to give masses to all the fermions of the theory.

We show that Einstein's gravity can be induced from a topological sigma model.

We analyze the effective action of the Green-Schwarz heterotic σ-model. We also discuss the Lorentz transformation properties when the theory is quantized according to the Kallosh procedure of truncating the Batalin-Vilkovisky tower of ghosts.

We show that the β-function of N = 2 superconformal models perturbed by a slightly relevant chiral superfield does not have non-trivial IR fixed points to all orders in perturbation theory.

It is shown that models containing both SU(2) singlet fermions and a singlet Higgs have interesting effects on the electric dipole moment of the electron. Unlike the neutron dipole moment, there is no QCD suppression in this case. It is thus possible to find useful constraints on models that include both these kinds of singlets.

We investigate a CP violating observable, the μ-polarization, in η → μ⁺μ⁻ in several models with the standard gauge group. The CP violating parameters are constrained by the experimental upper bound on the neutron electric dipole moment. Among the models considered here, it was found that those with leptoquark scalars dominate the contributions to μ-polarization in η → μ⁺μ⁻. μ-polarization can be of order 10⁻³.

It is rigorously shown that the amplitude for the decay Z → πγ must fall at least as fast as . Consequently its branching ratio must be smaller than 10⁻⁴; with slightly less conservative assumptions, this limit reduces to 5 × 10⁻⁶. The anomaly, the triangle graph and the Ward identities are shown to be consistent with both these bounds and the rate for π⁰ → 2γ.