Λb\Lambda_b Decays into Λ\Lambda-Vector

A complete study of the angular distributions of the processes, $\Lambda_b \to {\Lambda} V(1^-)$, with $\Lambda \to p {\pi}^-$ and $V (J/{\Psi}) \to {\ell}^+ {\ell}^-$ or $V ({\rho}^0,\omega) \to {\pi}^+ {\pi}^-,$ is performed. Emphasis is put on the initial $\Lambda_b$ polarization produced in the proton-proton collisions. The polarization density-matrices as well as angular distributions are derived and help to construct T-odd observables which allow us to perform tests of both Time-Reversal and CP violation.Comment: 10 pages, 2 figure

The pion wave function in covariant light-front dynamics

The structure of the pion wave function in the relativistic constituent quark model is investigated in the explicitly covariant formulation of light-front dynamics. We calculate the two relativistic components of the pion wave function in a simple one-gluon exchange model and investigate various physical observables: decay constant, charge radius, electromagnetic and transition form factors. We discuss the influence of the full relativistic structure of the pion wave function for an overall good description of all these observables, including both low and high momentum scales.Comment: 12 pages, 10 figure

K* resonance effects on direct CP violation in B -> pi pi K

Charged and neutral B decays into two charged pions and a charged or a neutral kaon are analyzed within the QCD factorization scheme where final state interactions before and after hadronization are included. The K*(892) and K*(1430) resonance effects are taken into account using the presently known pion-Kaon strange vector and scalar form factors. The weak decay amplitudes, which are calculated at leading power in Lambda_QCD/m_b and at the next-to-leading order in the strong coupling constant, include the hard scattering and annihilation contributions. The end point divergences of these weak final state interactions are controlled by two complex parameters determined through a fit to the available effective mass and helicity angle distribution, CP asymmetry and K*(892) branching ratio data. The predicted K*(1430) branching ratios and the calculated direct CP violation asymmetries are compared to the Belle and BABAR Collaboration data.Comment: Comments: 22 pages, 2 figures and 3 tables. In this new version, the results are unchanged, but, the last paragraph of the Section "RESULTS AND SUMMARY" (now called "RESULTS AND DISCUSSION") has been replaced by a new Section "SUMMARY AND OUTLOOK". To appear in Physical Review

HARLEM IN SHAKESPEARE AND SHAKESPEARE IN HARLEM: THE SONNETS OF CLAUDE MCKAY, COUNTEE CULLEN, LANGSTON HUGHES, AND GWENDOLYN BROOKS

This study responds to the need for an understanding of the relation of form and political critique within the sonnet form, and hopes to demonstrate that the sonnet can be used to effectively articulate the experience of racism, especially the Du Boisian concept of double- consciousness, a sense of two-ness born of being both black and American. The fundamental structure of the sonnet (octave, volta, sestet) is dialectical; it contests the idea it just introduced (Caplan, Poetic Form: An Introduction 75). The sonnet\u27s self-reflexive structure has been adopted and adapted by poets such as McKay, Cullen, Hughes, and Brooks. The formal and social characteristics of sonnets by African-Americans function synergistically: the way that the octave and the sestet respond to each other in a single poem is also similar to the call-and- response movement of African American oral culture. Its tendency to mix two unlike things is like Harlem itself: a compressed space where the street sweeper rubs shoulders with the business tycoon. Perhaps most importantly, the sonnet can be a Trojan horse, a genteel container that conceals a potentially subversive message. This study is constructed around related lines of questioning: First, why did African American poets, in an era usually associated with free verse, choose to adopt a traditional form? Second, how do African American poets adapt a European form as a lens into African American experience? Sonnets by African Americans reflect the complexity of a seemingly simple triangulation between the traditional requirements of form, the promise of equality, and the reality of racism. African American poets infuse Harlem in Shakespeare, pouring black consciousness into the European form, and they raise Shakespeare in Harlem, elevating the status of African American forms to the highest levels of literary art. At the same time, this study demonstrates the value of a prosody-based approach for examining how small formal details contribute substantially to the reader\u27s impression of the sonnet. These poets deploy the rules of the sonnet ingeniously and unexpectedly. Additionally, the sonnet is a way to separate from and simultaneously be a part of the dominant culture by writing a critical message in a recognizable form. Black culture can criticize white culture, while at the same time acknowledging the mutual, inescapable relationship that binds blacks and white Americans together. Additionally, the sonnet is a way to separate from and simultaneously be a part of the dominant culture by writing a critical message in a recognizable form. Black culture can criticize white culture, while at the same time acknowledging the mutual, inescapable relationship that binds blacks and white Americans together

A sub-product construction of Poincare-Einstein metrics

Given any two Einstein (pseudo-)metrics, with scalar curvatures suitably related, we give an explicit construction of a Poincar\'e-Einstein (pseudo-)metric with conformal infinity the conformal class of the product of the initial metrics. We show that these metrics are equivalent to ambient metrics for the given conformal structure. The ambient metrics have holonomy that agrees with the conformal holonomy. In the generic case the ambient metric arises directly as a product of the metric cones over the original Einstein spaces. In general the conformal infinity of the Poincare metrics we construct is not Einstein, and so this describes a class of non-conformally Einstein metrics for which the (Fefferman-Graham) obstruction tensor vanishes.Comment: 23 pages Minor correction to section 5. References update

Pseudoscalar-scalar transition form factors in covariant light front dynamics

In an explicitly covariant light-front formalism, we analyze transition form factors between pseudoscalar and scalar mesons. Application is performed in case of the $B \to f_0(980)$ transition in the full available transfer momentum range $q^2$.Comment: 4 pages, 4 figures. Talk given at the XXXIII International Conference on High Energy Physics, ICHEP06, Moscow, 26 July-02 Augus

Form factors in B->f0(980) and D->f0(980) transitions from dispersion relations

Within the dispersion relation approach we give the double spectral representation for space-like and time-like B-> f_0(980) and D-> f_0(980) transition form factors in the full q^2 range. The spectral densities, being the input of the dispersion relations, are obtained from a triangle diagram in the relativistic quark model.Comment: Talk given at MESON 2006, Krakow, 9-13 June 200

Spontaneous Edge Currents for the Dirac Equation in Two Space Dimensions

Spontaneous edge currents are known to occur in systems of two space dimensions in a strong magnetic field. The latter creates chirality and determines the direction of the currents. Here we show that an analogous effect occurs in a field-free situation when time reversal symmetry is broken by the mass term of the Dirac equation in two space dimensions. On a half plane, one sees explicitly that the strength of the edge current is proportional to the difference between the chemical potentials at the edge and in the bulk, so that the effect is analogous to the Hall effect, but with an internal potential. The edge conductivity differs from the bulk (Hall) conductivity on the whole plane. This results from the dependence of the edge conductivity on the choice of a selfadjoint extension of the Dirac Hamiltonian. The invariance of the edge conductivity with respect to small perturbations is studied in this example by topological techniques