Modern Physics Letters A

Using steady state leaky box and closed galaxy models and the latest primary proton spectrum based on the directly measured data along with the accelerator data on production, the flux ratio in the interstellar medium has been estimated in the spectral range from 6 to 100 GeV/n. The derived result is in approximate agreement with the balloon borne calorimeter data of Golden et al.

We have closed galaxy model for the estimation of the old component and young component of primary proton spectrum from the composite primary proton spectrum obtained from the recent experiments performed by Menn et al., Webber et al., Seo et al., JACEE and others. The derived results differ slightly from the results of Protheroe, Pal and Bhattacharyya.

We study the WWγ vertex through the process γq→Wq′ where q denotes the quark at a future high energy collider. The differential cross-section for the photoproduction process γq→Wq′ is computed with both anomalous magnetic moment κ and electric quadrupole moment λ for the W-boson. The deep inelastic photoproduction of W^± is also calculated in a quark-parton model.

A generalization of the Yang–Mills covariant derivative, that uses both vector and scalar fields and transforms as a four-vector contracted with Dirac matrices, is used to simplify the Glashow–Weinberg–Salam model. Since SU(3) assigns the wrong hypercharge to the Higgs boson, it is necessary to use a special representation of U(3) to obtain all the correct quantum numbers. A surplus gauge scalar boson emerges in the process, but it uncouples from all other particles.

About two-thirds of spiral galaxies are classified as barred: only one-third is very strongly barred (SB) and the other is classified as "intermediate" SB galaxies, i.e. galaxies with a faint bar. Bars are quasi-stationary density waves originated by swing amplification mechanisms. We use smooth-particle-hydrodynamical simulations to give insights into the role triaxiality of the halo on triggering the bar instability and to investigate how tidal interactions act on the bar evolution. We argue that the triaxiality of the primordial halo and the weight of the halo have a fundamental role in monitoring the incidence of the bar instability in spiral galaxies.

We consider ββ_0ν decay induced by light Majorana neutrino exchange between decaying nucleons, accompanied by, in particular, the slepton exchange inside a nucleon. This contribution to ββ_0ν is generated from the R_p violating terms and the mixing of the standard light neutrinos with neutral heavy particles or light sterile neutrinos. To determine the unknown mixing factor Δ, we take into account the four-neutrino model with three ordinary neutrinos and one sterile neutrino. Imposing the current experimental lower half-life limit, a set of constraints on and is obtained. Comparing with the limits on the products of the individual bounds on λ and λ′, we find that the former is stronger while the latter is weaker.

The pseudo-Riemannian Lorentzian wormholes are extended to Weitzenböck T₄ teleparallel space–times. Non-static wormholes are shown to possess a Cartan torsion which influences the shape of the wormhole. In the static, all components of the torsion form are shown to vanish at the wormhole throat. At infinite time, coordinate torsion seems to be stable in the sense that not all components of torsion vanish. When the wormhole is sealed off torsion just one component of torsion remains finite while the others diverge yielding a torsion singularity.

We give a Bäcklund transformation connecting a generic 2-D dilaton gravity theory to a generally covariant free field theory. This transformation provides an explicit canonical transformation relating both theories.

This letter studies the quantum Liouville field theory on a manifold with boundary. The boundary conformal Ward identity (CWI) is written and its semiclassical approximation is analyzed. This establishes a method of finding the accessory parameters of the theory with boundary. The boundary structure constants of the theory are defined and the functional equations which determine them are derived.

The possibility of adding an SU(2) horizontal symmetry to the 331 model is studied. It is found that simple, anomaly-free fermion assignments can be made which lead to plausible results for fermion masses and mixings. In particular, all particles of the first generation are massless at tree-level, and the CKM matrix acquires a realistic form.