Isovector axial-vector form factors of octet baryons in QCD

We compute the diagonal isovector axial-vector as well as induced pseudoscalar form factors of nucleon, $\Sigma$ and $\Xi$ baryons by employing the light-cone QCD sum rules to leading order in QCD and including distribution amplitudes up to twist 6. Extrapolating our sum-rules results to low-momentum transfers, we make a comparison with experimental and lattice-QCD results where we can achieve a nice qualitative and quantitative agreement.Comment: 9 pages, 3 figure

On the calculation of covariant expressions for Dirac bilinears

In this article, various approaches to calculate covariant expressions for the bilinears of Dirac spinors are presented. For this purpose, algebraic equations defining Dirac spinors are discussed. Following that, a covariant approach for spacetime parameterization is presented and the equations defining Dirac spinors are written fully in terms of Lorentz scalars. After presenting how the tensorial bilinears can be reduced to combinations of scalar bilinears with appropriate Lorentz structures, a covariant recipe for the calculation of scalar bilinears is provided.Comment: 10 pages, 1 figur

Fourth generation effects in processes induced by "b -> s" transition

We study the effects of sequential fourth quark generation in rare "B -> K(K*) l^+ l^-" decays induced by "b -> s" transition and in "B_s^0 - bar{B}_s^0" mixing. Using the experimental values on branching ratios of the "B -> X_s gamma" and "B -> K(K*) l^+ l^-" decays, the allowed regions for \vel V_{tb} V_{ts}^\ast\ver and "|V_{t'b} V_{t's}*| are determined as a function of the (t') quark mass.Comment: 18 pages, 8 figures, LaTeX formatte

Octet baryon magnetic moments in light cone QCD sum rules

Octet baryon magnetic moments are calculated in framework of the light cone QCD sum rules. The analysis is carried for the general form of the interpolating currents for octet baryons. A comparison of our results on the magnetic moments of octet baryons with the predictions of other approaches and experimental data is presented.Comment: 20 pages, 10 figures, 1 Table, LaTeX formatte