Phase synchronization of slip in laboratory slider system

International audienceIn the present study the character of slip regimes in laboratory spring-slider system under weak external periodical forcing has been investigated. We report the experimental evidence of phase synchronization (PS) in a slip dynamics, induced by the external periodic electromagnetic (EM) impact. The quality of synchronization depends on the intensity and frequency of the applied field; the corresponding Arnold's tongue region is constructed. Application of special techniques (measuring phase differences, phase diffusion coefficient, Shannon entropy, Recurrence Quantification Analysis) allows quantitative assessment of the strength of synchronization of microslips with EM impact. It is also shown that the character of power law relationship in acoustic emission amplitude (energy) distribution also undergoes significant changes at changing excitation intensity

Double-Lepton Polarization Asymmetries and Branching Ratio in B \rar K_{0}^{*}(1430) l^+ l^- transition from Universal Extra Dimension Model

We investigate the B \rar K_{0}^{*}(1430) l^+ l^- transition in the Applequist-Cheng-Dobrescu model in the presence of a universal extra dimension. In particular, we calculate double lepton polarization asymmetries and branching ratio related to this channel and compare the obtained results with the predictions of the standard model. Our analysis of the considered observables in terms of radius $R$ of the compactified extra-dimension as the new parameter of the model show a considerable discrepancy between the predictions of two models in low $\frac{1}{R}$ values.Comment: 12 Pages, 15 Figures and 1 Tabl

B to strange tensor meson transition in a model with one universal extra dimension

We analyze the semileptonic $B\to K_2^*(1430)l^+l^-$ transition in universal extra dimension model. In particular, we present the sensitivity of related observables such as branching ratio, polarization distribution and forward-backward asymmetry to the compactification factor (1/R) of extra dimension. The obtained results from extra dimension model show overall a considerable deviation from the standard model predictions for small values of the compactification factor. This can be considered as an indication for existence of extra dimensions.Comment: 10 Pges, 6 Figures and 2 Table

Laboratory study of electromagnetic initiation of slip

Recently Russian seismologists reported the triggering effect of MHD soundings on microseismic activity in the Central Asia test area.The paper focuses on an experimental test of the possibility of triggering the mechanical instability of a system that is close to critical state by a series of electromagnetic pulses.The mechanical system consisted of two pieces of rock;the upper piece can slip on the fixed supporting sample if the latter one is tilted up to the critical angle.In this state,the triggering of mechanical instability by some weak impact such as electrical pulse became more probable.The slope of support in the experiment is an analogue of tectonic stress in natural conditions.The preliminary experiments,carried out in a dry environment,at the humidity of atmosphere 30-50%,show that a strong EM-pulse induces sliding of a sample of rock (granite,basalt,labradorite)placed on the supporting sample which is inclined at the slope close to,but less than,the critical angle with a probability 0.07.PublishedJCR Journalope