Lepton Flavor Violating Photoleptonic Effect

We study lepton flavor violating analogs of the photoelectric effect, with a final $\mu$ or $\tau$ instead of an electron: $\gamma e\to \mu$ and $\gamma e\to \tau$. On the basis of the general parametrization of the matrix element of the electromagnetic current we estimate the upper limits for the cross sections and event rates of these processes, imposed by the current experimental bounds on $\mu\to e \gamma$ and $\tau\to e \gamma$ decays.Comment: 6 pages, 1 figure, RevTeX

Phase diagram of a two-dimensional system with anomalous liquid properties

Using Monte Carlo simulation techniques, we calculate the phase diagram for a square shoulder-square well potential in two dimensions that has been previously shown to exhibit liquid anomalies consistent with a metastable liquid-liquid critical point. We consider the liquid, gas and five crystal phases, and find that all the melting lines are first order, despite a small range of metastability. One melting line exhibits a temperature maximum, as well as a pressure maximum that implies inverse melting over a small range in pressure.Comment: 11 pages, 13 figure

Structural Effects of Carbon Monoxide Coordination to Carbon Centers. π and σ Bindings in Aliphatic Acyl \u3cem\u3eversus\u3c/em\u3e Aromatic Aroyl Cations

The binding of carbon monoxide to carbon centers has been examined with two series of aromatic and aliphatic oxocarbonium ions that are successfully isolated as crystalline and highly reactive (hygroscopic) aroylium and acylium salts with poorly coordinating counteranions. X-Ray crystallographic analyses at −150 °C afford precise structural parameters for the characteristic linear carbonyl bond (rCO) and the bond to the carbon centers (rCα). The correlations of these structural parameters evaluated for alkyl (Me, Et and i-Pr) and aryl (p-Me, 2,4,6-trimethyl, p-MeO and p-fluorophenyl) oxocarbonium ions with the corresponding carbonyl stretching frequencies in the solid-state (reflectance) IR spectra yield valuable insight into the binding mode of carbon monoxide. Most noteworthy is the synergic (π–σ) bonding in aroylium structures in contrast to the mainly σ bonding in acylium structures that are organic mimics for carbon monoxide bonding in classical and nonclassical metal carbonyls, respectively

B_s(d) - bar B_s(d) mixing constraints on flavor changing decays of t and b quarks

We study those dimension 6 effective operators which generate flavor-changing quark-gluon transitions of the third generation quarks, with t -> g + u(c) and b -> g + d(s), and which could be of interest for LHC experiments. We analyze the contribution of these operators to B_s(d) - bar B_s(d) mixing and derive limits on the corresponding effective couplings from the existing experimental data. The Standard Model gauge invariance relates these couplings to the couplings controlling t -> g + u(c). On this basis we derive upper limits for the branching ratios of these processes. We further show that forthcoming LHC experiments might be able to probe the studied operators and the physics beyond the Standard Model related to them.Comment: 6 pages, 1 figur

On Sterile neutrino explanation of LSND and MiniBooNE anomalies

We examine the compatibility between existing experimental data and a recently proposed explanation of the LSND and MiniBooNE anomalies, given in terms of a sterile neutrino $N$ whose decay is dominated by a radiative mode. We find that current experimental data on $\tau\rightarrow \mu\nu\nu\gamma$ decays are compatible with the sterile neutrino parameters required for the explanation of the anomalies, but $K\rightarrow \mu\nu\gamma$ shows a marginal tension with those parameters. We also propose experimental cuts on radiative $K$ decays that could test the sterile neutrino hypothesis better. Finally, we study the contribution of this sterile neutrino to $K\to\mu\nu e e$, and find that measurements of this process would provide powerful tests for the sterile neutrino explanation of the LSND and MiniBooNE anomalies, if the experimental cut on the invariant mass of the $e^{+}e^{-}$ pair could be reduced from its current value of 145 MeV to a value below 40 MeV.Comment: 6 pages, 2 figures, experimental cut taken into account, some conclusions change

Алгоритм оптимального синтезу стабілізатора наземного призначення

 Approaches to creation of the ground vehicle stabilizer optimal synthesis are considered. Features of the computational procedure of the optimal synthesis for the studied system are defined. Simulation results are represented. Рассмотрены подходы к созданию алгоритма оптимального синтеза стабилизатора наземного назначения. Определены особенности вычислительной процедуры оптимального синтеза системы исследуемого класса. Представлены результаты моделирования синтезированной системы. Розглянуто підходи до створення алгоритму оптимального синтезу стабілізатора наземного призначення. Визначено особливості обчислювальної процедури оптимального синтезу системи досліджуваного класу. Надано результати моделювання синтезованої системи