Exclusive B -> K^* l^+ l^- decay with polarized K^* and new physics effects

Using the most general, model independent effective Hamiltonian, the branching ratio of the (B -> K^* l^+ l^-) decay, when K^* meson is longitudinally or transversally polarized, is presented. The dependence of the branching ratio on the new Wilson coefficients, when K^* meson is polarized, is studied. It is observed that the branching ratio is very sensitive to the vector and tensor type interactions, which will be useful in search of new physics beyond the Standard Model.Comment: 13 pp, 6 figures (postscript formatted), LaTex formatte

Encapsulated thermoacoustic projector based on freestanding carbon nanotube film

A suspended nanotube film (or films) producing sound by means of the thermoacoustic (TA) effect is encapsulated between two plates, at least one of which vibrates, to enhance sound generation efficiency and protect the film. To avoid the oxidation of carbon nanotubes at elevated temperatures and reduce the thermal inertia of surrounding medium the enclosure is filled with inert gas (preferably with high heat capacity ratio, γ=Cp/Cv, and low heat capacity, Cp). To generate sound directly as the first harmonic of applied audio signal without use of an energy consuming dc biasing, an audio signal modulated carrier frequency at much higher frequency is used to provide power input. Various other inventive means are described to provide enhanced projected sound intensity, increased projector efficiency, and lengthened projector life, like the use of infrared reflecting coatings and particles on the projector plates, non-parallel sheet alignment in sheet stacks, and cooling means on one projector side.Board of Regents, University of Texas Syste

General analysis of lepton polarizations in rare B -> K^* l^+ l^- decay beyond the standard model

The general analysis of lepton polarization asymmetries in rare B -> K^* l^+ l^- decay is investigated. Using the most general, model independent effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for l^- and l^+ and combinations of them are presented. The dependence of lepton polarizations and their combinations on new Wilson coefficients are studied in detail. Our analysis shows that the lepton polarization asymmetries are very sensitive to the scalar and tensor type interactions, which will be very useful in looking for new physics beyond the standard model.Comment: 29 pp, 15 figure

B--> K^* l^+ l^- decay in the two Higgs doublet model with flavor changing neutral currents

We study the decay width, forward-backward asymmetry and the longitudinal lepton polarization for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse the dependencies of these quantities on the the selected parameters, \xi^{U,D}, of model III including the next to leading QCD corrections. It is found that to look for charged Higgs effects, the measurements of the branching ratio, forward-backward asymmetry and the longitudinal lepton polarization for the decay B --> K^* l^+ l^- are promising.Comment: 17 pages, 6 figure

Lepton polarization and CP-violating effects in "B -> K^* tau^+ tau^-" decay in standard and two Higgs doublet models

The most general model independent expressions for the CP-violating asymmetry, longitudinal, transversal and normal polarizations of leptons are derived. Application of these general results to the concrete models such as Standard model and three different types of two Higgs doublet model is discussed.Comment: 18 pages, 8 postscripted figure

Band edge noise spectroscopy of a magnetic tunnel junction

We propose a conceptually new way to gather information on the electron bands of buried metal(semiconductor)/insulator interfaces. The bias dependence of low frequency noise in Fe$_{1-x}$V$_{x}$/MgO/Fe (0 $<$ x $<$ 0.25) tunnel junctions show clear anomalies at specific applied voltages, reflecting electron tunneling to the band edges of the magnetic electrodes. The change in magnitude of these noise anomalies with the magnetic state allows evaluating the degree of spin mixing between the spin polarized bands at the ferromagnet/insulator interface. Our results are in qualitative agreement with numerical calculations

Reversible Superconductivity in Electrochromic Indium-Tin Oxide Films

Transparent conductive indium tin oxide (ITO) thin films, electrochemically intercalated with sodium or other cations, show tunable superconducting transitions with a maximum $T_c$ at 5 K. The transition temperature and the density of states, $D(E_F)$ (extracted from the measured Pauli susceptibility $\chi_p$ exhibit the same dome shaped behavior as a function of electron density. Optimally intercalated samples have an upper critical field $\approx 4$ T and $\Delta/{k_BT_c} \approx 2.0$. Accompanying the development of superconductivity, the films show a reversible electrochromic change from transparent to colored and are partially transparent (orange) at the peak of the superconducting dome. This reversible intercalation of alkali and alkali earth ions into thin ITO films opens diverse opportunities for tunable, optically transparent superconductors

CP violation in polarized B-> pi ell+ ell- and B-> rho ell+ ell- decays

We study the decay rate and the CP violating asymmetry of the exclusive B-> pi ell+ ell- and B-> rho ell+ ell- decays in the case where one of the final leptons is polarized. We calculate the contributions coming from the individual polarization states in order to identify a so-called wrong sign decay, which is a decay with a given polarization, whose width and CP asymmetry are smaller as compared to the unpolarized one. The results are presented for electron and tau leptons. We observe that in particular decay channels, one can identify a wrong sign decay which is more sensitive to new physics beyond the Standard Model.Comment: 24 pages, 10 figures; minor errors and misprints corrected, references added, version to be published in EPJ

Fourth generation effects in rare exclusive B -> K^* l^+ l^- decay

Influence of the fourth generation, if ever exists, on the experimentally measurable quantities such as invariant dilepton mass distribution, lepton forward-backward asymmetry, and the ratio (Gamma_L/Gamma_T) of the decay widths when K* meson is longitudinally and transversally polarized, is studied. Using the experimental results on the branching ratios for the (B -> X_s) gamma and semileptonic (B -> X_c l nu) decays, the two possible solutions of the 4x4 Cabibbo-Kobayashi-Maskawa factor (V_{t's} V_{t^'b}) are obtained as a function of the t'-quark mass. It is observed that the results for the above-mentioned physical quantities are essentially different from the standard model predictions only for one solution of the CKM factor. In this case the above-mentioned physical quantities can serve as efficient tools in search of the fourth generation. The other solution yields almost identical results with the SM.Comment: 19 pages, 10 postscripted figures, LaTeX formatte

Rare decays B→Xsτ+τ−B\to X_s\tau^+\tau^- and Bs→τ+τ−γB_s\to \tau^+\tau^-\gamma in technicolor with scalars

We examine the rare decays $B\to X_s\tau^+\tau^-$ and $B_s\to\tau^+\tau^- \gamma$ in the framework of technicolor with scalars. The contributions from both the neutral and charged scalars predicted in this model are evaluated. We find that the branching ratios could be enhanced over the standard model predictions by a couple of orders of magnitude in some part of parameter space. The forward-backward asymmetry and the distributions of differential branching ratios are also found to differ significantly from the standard model results. Such large new physics effects might be observable in the new generation of B experiments.Comment: NPB version. 15 pages, 6 figure