Mass and CKM Matrices of Quarks and Leptons, the Leptonic CP-phase in neutrino oscillations

A general approach for construction of quark and lepton mass matrices is formulated. The hierarchy of quarks and charged leptons ("electrons") is large, it leads using the experimental values of mixing angles to the hierarchical mass matrix slightly deviating from one's suggested earlier by Stech and including naturally the CP-phase. The same method based on the rotation of generation numbers in the diagonal mass matrix is used in the electron-neutrino sector of theory, where neutrino mass matrix is determined by the Majorano see-saw approach. The hierarchy of neutrino masses, much smaller than for quarks, was used including all existing (even preliminary) experimental data on neutrinos mixing. The leptonic mass matrix found in this way includes not known value of the leptonic CP-phase. It leads to a large $\nu_\mu \nu_\tau$ oscillations and suppresses the $\nu_e\nu_\tau$ and also $\nu_e \nu_\mu$ oscillations. The explicit expressions for the probabilities of neutrino oscillation were obtained in order to specify the role of leptonic CP-phase. The value of time reversal effect (proportional to $\sin\delta'$) was found to be small $\sim 1$. However, a dependence of the values of $\nu_e \nu_\mu, \nu_e \nu_\tau$ transition probabilities, averaged over oscillations, on the leptonic CP-phase has found to be not small - of order of tens percent.Comment: 21 pages, 2 figures, some correction

Academic language socialisation in high school writing conferences

This study examines multilingual high school writers’ individual talk with their teachers in two advanced English language development classes to observe how such talk shapes linguistically diverse adolescents’ writing. Addressing adolescent writers’ language socialization through microethnographic discourse analysis, the author argues that teachers’ oral responses during writing conferences can either scaffold or deter students’ socialization into valued ways of using academic language for school writing. She suggests what forms of oral response provide scaffolding and what forms might limit multilingual adolescent learners’ academic literacy. Constructive interactions engaged students in dialogue about their writing, and students included content or phrasing from the interaction in their texts. Unhelpful interactions failed to foster students’ language development in observable ways. Although teachers attempted to scaffold ideas and language, they often did not guide students’ discovery of appropriate forms or points. These interactions represent restrictive academic language socialization: while some students did create academic texts, they learned little about academic language use

Multi-dimensional classical and quantum cosmology: Exact solutions, signature transition and stabilization

We study the classical and quantum cosmology of a $(4+d)$-dimensional spacetime minimally coupled to a scalar field and present exact solutions for the resulting field equations for the case where the universe is spatially flat. These solutions exhibit signature transition from a Euclidean to a Lorentzian domain and lead to stabilization of the internal space, in contrast to the solutions which do not undergo signature transition. The corresponding quantum cosmology is described by the Wheeler-DeWitt equation which has exact solutions in the mini-superspace, resulting in wavefunctions peaking around the classical paths. Such solutions admit parametrizations corresponding to metric solutions of the field equations that admit signature transition.Comment: 15 pages, two figures, to appear in JHE

Particle motion and gravitational lensing in the metric of a dilaton black hole in a de Sitter universe

We consider the metric exterior to a charged dilaton black hole in a de Sitter universe. We study the motion of a test particle in this metric. Conserved quantities are identified and the Hamilton-Jacobi method is employed for the solutions of the equations of motion. At large distances from the black hole the Hubble expansion of the universe modifies the effective potential such that bound orbits could exist up to an upper limit of the angular momentum per mass for the orbiting test particle. We then study the phenomenon of strong field gravitational lensing by these black holes by extending the standard formalism of strong lensing to the non-asymptotically flat dilaton-de Sitter metric. Expressions for the various lensing quantities are obtained in terms of the metric coefficients.Comment: 8 pages, RevTex, 1 eps figures; discussion improved; typos corrected; references adde

Gravitation with superposed Gauss--Bonnet terms in higher dimensions: Black hole metrics and maximal extensions

Our starting point is an iterative construction suited to combinatorics in arbitarary dimensions d, of totally anisymmetrised p-Riemann 2p-forms (2p\le d) generalising the (1-)Riemann curvature 2-forms. Superposition of p-Ricci scalars obtained from the p-Riemann forms defines the maximally Gauss--Bonnet extended gravitational Lagrangian. Metrics, spherically symmetric in the (d-1) space dimensions are constructed for the general case. The problem is directly reduced to solving polynomial equations. For some black hole type metrics the horizons are obtained by solving polynomial equations. Corresponding Kruskal type maximal extensions are obtained explicitly in complete generality, as is also the periodicity of time for Euclidean signature. We show how to include a cosmological constant and a point charge. Possible further developments and applications are indicated.Comment: 13 pages, REVTEX. References and Note Adde

No hair for spherical black holes: charged and nonminimally coupled scalar field with self--interaction

We prove three theorems in general relativity which rule out classical scalar hair of static, spherically symmetric, possibly electrically charged black holes. We first generalize Bekenstein's no--hair theorem for a multiplet of minimally coupled real scalar fields with not necessarily quadratic action to the case of a charged black hole. We then use a conformal map of the geometry to convert the problem of a charged (or neutral) black hole with hair in the form of a neutral self--interacting scalar field nonminimally coupled to gravity to the preceding problem, thus establishing a no--hair theorem for the cases with nonminimal coupling parameter $\xi<0$ or $\xi\geq {1\over 2}$. The proof also makes use of a causality requirement on the field configuration. Finally, from the required behavior of the fields at the horizon and infinity we exclude hair of a charged black hole in the form of a charged self--interacting scalar field nonminimally coupled to gravity for any $\xi$.Comment: 30 pages, RevTeX. Sec.IV corrected, simplified and shortened. Corrections to Sec.IIA between Eqs. 2.7 and Eq.2.1. First two paragraphs of Sec. VC new. To appear Phys. Rev. D, Oct. 15, 199

Generalised Israel Junction Conditions for a Gauss-Bonnet Brane World

In spacetimes of dimension greater than four it is natural to consider higher order (in R) corrections to the Einstein equations. In this letter generalized Israel junction conditions for a membrane in such a theory are derived. This is achieved by generalising the Gibbons-Hawking boundary term. The junction conditions are applied to simple brane world models, and are compared to the many contradictory results in the literature.Comment: 4 page

Radionic Non-uniform Black Strings

Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of the black strings. From the brane point of view, the black string appears as the deformed dilatonic black hole which becomes dilatonic black hole in the single brane limit and reduces to the Reissner-Nordstr\"om black hole in the close limit of two-branes. The stability of solutions is demonstrated using the catastrophe theory. From the bulk point of view, the black strings are proved to be non-uniform. Nevertheless, the zeroth law of black hole thermodynamics still holds.Comment: 9 pages, 6 figure

Gravitational Coupling and Dynamical Reduction of The Cosmological Constant

We introduce a dynamical model to reduce a large cosmological constant to a sufficiently small value. The basic ingredient in this model is a distinction which has been made between the two unit systems used in cosmology and particle physics. We have used a conformal invariant gravitational model to define a particular conformal frame in terms of large scale properties of the universe. It is then argued that the contributions of mass scales in particle physics to the vacuum energy density should be considered in a different conformal frame. In this manner, a decaying mechanism is presented in which the conformal factor appears as a dynamical field and plays a key role to relax a large effective cosmological constant. Moreover, we argue that this model also provides a possible explanation for the coincidence problem.Comment: To appear in GR

Influence of a Brane Tension on Phantom and Massive Scalar Field Emission

We elaborate the signature of the extra dimensions and brane tension in the process of phantom and massive scalar emission in the spacetime of (4+n)-dimensional tense brane black hole. Absorption cross section, luminosity of Hawking radiation and cross section in the low-energy approximation were found. We envisage that parameter connected with the existence of a brane imprints its role in the Hawking radiation of the considered fields.Comment: 7 pages, * figures, RevTex, to be published in General Relativity and Gravitatio