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

Reduced Density Matrix Approach to Phononic Dissipation in Friction

Understanding mechanisms for energy dissipation from nanoparticles in contact with large samples is a central problem in describing friction microscopically. Calculation of the reduced density matrix appears to be the most suitable metho to study such systems that are coupled to a large environment. In this paper the time evolution of the reduced density matrix has been evaluated for an arbitrary system coupled to a heat reservoir. The formalism is then applied to study the vibrational relaxation following the stick-slip motion of a small adsorbate on a surface. The frequency dependence of the relaxation time is also determined.Comment: 16 pages, 3 figures (included), revte