Lepton energy moments in semileptonic charm decays

We search for signals of Weak Annihilation in inclusive semileptonic D decays. We consider both the widths and the lepton energy moments, which are quite sensitive probes. Our analysis of Cleo data shows no clear evidence of Weak Annihilation, and allows us to put bounds on their relevance in charmless B semileptonic decays.Comment: 10 pages, 3 figures. Added discussion, version as publishe

Search for Lepton Flavor Violating tau Decays into Three Leptons

We search for lepton-flavor-violating tau decays into three leptons (electron or muon) using 535 fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No evidence for these decays is observed, and we set 90% confidence level upper limits on the branching fractions of (2.0-4.1)x10^-8. These results improve upon our previously published upper limits by factors of 4.9 to 10.Comment: 11 pages, 4 figures, submitted to Phys. Lett.

Search for the lepton flavour violating decay τ − → μ − μ + μ −

A search for the lepton flavour violating decay $\tau^-\to \mu^-\mu^+\mu^-$ is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of $1.0\mathrm{\,fb}^{-1}$ of proton-proton collisions at a centre-of-mass energy of $7\mathrm{\,Te\kern -0.1em V}$ and $2.0\mathrm{\,fb}^{-1}$ at $8\mathrm{\,Te\kern -0.1em V}$. No evidence is found for a signal, and a limit is set at $90\%$ confidence level on the branching fraction, $\mathcal{B}(\tau^-\to \mu^-\mu^+\mu^-) < 4.6 \times 10^{-8}$.Comment: 20 pages, 10 figures, published as JHEP 02 (2015) 12

Growth In-Place Integration of Metallic Nanowires into MEMS Gas Flow Sensors

This work demonstrates a process for the in-place growth of metallic nanowires in microsystems. The wires are arranged in bunches, the so called nanowire arrays. The process expands the established ion track etch method and combines it with conventional MEMS technologies like photolithography. The process is described in detail and demonstrated by fabricating a calorimetric gas flow sensor with nanowire arrays. Two serially connected nanowire arrays are placed before and behind an electrically heated conductor on a glass substrate. The nanowire arrays work as fast temperature sensing elements to determine the gas flow over the sensor. The steady state sensor characteristics are measured, the time constant is estimated by a numerical simulation

Modeling of large deflections of carbon fibers in cilia-based piezoelectric actuators

Cilia-based piezoelectric actuators use piezo elements as source of vibrations and a friction layer of inclined microscopic cilia for anisotropic friction to generate displacement. Hence, large deflections of the cilia are required for large displacements in the actuator. To model these displacements, the analytical approach is carried out in this paper, instead of using a black-box-software solution. For this, nonlinear kinematic relations are used to set the characterizing differential equation of a single fiber. The large displacements have negative longitudinal and perpendicular displacements to the initial position of the fiber. For this, high order theories of elastic bending are applied

Patterned arrays of capped platinum nanowires with quasi-elastic mechanical response to lateral force

n this Letter, we describe the electrodeposition of capped, micro-sized Pt nanowire arrays in ion-track etched polymer templates and measure their collective mechanical response to an external force. By using an aperture mask during the irradiation process, it was possible to restrict the creation of pores in the templates to defined areas, allowing the fabrication of small nanowire arrays in different geometries and sizes. The simultaneous and highly reliable formation of many nanowire arrays was achieved using a pulsed electrodeposition technique. After deposition, the polymer matrix was removed using a gentle, dry oxygen plasma treatment, resulting in an excellent preservation of the array nanostructure as confirmed by scanning electron microscopy. A force measuring station was set up to perform mechanical characterization series on free-standing arrays. The nanowire arrays show a high robustness and respond sensitively to the applied force, making them attractive as spring elements in miniaturized inertial sensors, for example