The Flavor Structure of the Three-Site Higgsless Model

We study the flavor structure of the three-site Higgsless model and evaluate the constraints on the model arising from flavor physics. We find that current data constrain the model to exhibit only minimal flavor violation at tree level. Moreover, at the one-loop level, by studying the leading chiral logarithmic corrections to chirality-preserving Delta F = 1 and Delta F = 2 processes from new physics in the model, we show that the combination of minimal flavor violation and ideal delocalization ensures that these flavor-changing effects are sufficiently small that the model remains phenomenologically viable.Comment: 23 pages, 22 pdf figures include

An Internal Current Controlled BLDC Motor Drive Supplied with PV Fed High Voltage Gain DC-DC Converter

The paper presents an efficient speed control of brushless DC (BLDC) motor drive for photo-voltaic (PV) system fed system. A high-gain DC-DC converter is employed in the system to boost the PV system low output voltage to a level required for the drive system. High-gain DC-DC converter is operated in closed-loop mode to attain accurate and steady output. The converter (VSI) for BLDC is switched at fundamental frequency and thus reducing high frequency switching losses. Internal current control method is developed and employed for the speed control of PV fed BLDC motor. The appropriateness of the internal current controller for the speed control of PV fed BLDC motor is verified for increamental speed with fixed torque and decreamental speed with fixed torque operating conditions. The system is developed and results are developed using MATLAB/SIMULINK softwar

Low-Energy Effective Theory, Unitarity, and Non-Decoupling Behavior in a Model with Heavy Higgs-Triplet Fields

We discuss the properties of a model incorporating both a scalar electroweak Higgs doublet and an electroweak Higgs triplet. We construct the low-energy effective theory for the light Higgs-doublet in the limit of small (but nonzero) deviations in the rho parameter from one, a limit in which the triplet states become heavy. For small deviations in the rho parameter from one, perturbative unitarity of WW scattering breaks down at a scale inversely proportional to the renormalized vacuum expectation value of the triplet field (or, equivalently, inversely proportional to the square-root of the deviation of the rho parameter from one). This result imposes an upper limit on the mass-scale of the heavy triplet bosons in a perturbative theory; we show that this upper bound is consistent with dimensional analysis in the low-energy effective theory. Recent articles have shown that the triplet bosons do not decouple, in the sense that deviations in the rho parameter from one do not necessarily vanish at one-loop in the limit of large triplet mass. We clarify that, despite the non-decoupling behavior of the Higgs-triplet, this model does not violate the decoupling theorem since it incorporates a large dimensionful coupling. Nonetheless, we show that if the triplet-Higgs boson masses are of order the GUT scale, perturbative consistency of the theory requires the (properly renormalized) Higgs-triplet vacuum expectation value to be so small as to be irrelevant for electroweak phenomenology.Comment: Revtex, 11 pages, 7 eps figures included; references updated and three footnotes adde

Custodial Isospin Violation in the Lee-Wick Standard Model

We analyze the tension between naturalness and isospin violation in the Lee-Wick Standard Model (LW SM), by computing tree-level and fermionic one-loop contributions to the post-LEP electroweak parameters and the Zbb coupling. The model is most natural when the LW partners of the gauge bosons and fermions are light, but small partner masses can lead to large isospin violation. The post-LEP parameters yield a simple picture in the LW SM: the gauge sector contributes to Y and W only, with leading contributions arising at tree-level, while the fermion sector contributes to S-hat and T-hat only, with leading corrections arising at one loop. Hence, W and Y constrain the masses of the LW gauge bosons to satisfy M1, M2 > 2.4 TeV at 95% CL. Likewise, experimental limits on T-hat reveal that the masses of the LW fermions must satisfy Mq, Mt > 1.6 TeV at 95% CL if the Higgs mass is light and tend to exclude the LW SM for any LW fermion masses if the Higgs mass is heavy. Contributions from the top-quark sector to the Zbb coupling can be even more stringent, placing a lower bound of 4 TeV on the LW fermion masses at 95% CL.Comment: 16 pages, 8 embedded eps figure

Surface tension driven convection in viscoelastic liquids with thermorheological effect

Oscillatory onset of convection is studied numerically for Rivlin-Ericksen, Maxwell and Jeffreys liquids by considering free-free and rigid-free isothermal/adiabatic boundaries. The effect of variable viscosity parameter is shown to destabilize the system. The problem reveals the stabilizing nature of strain retardation parameter and the destabilizing nature of stress relaxation parameter, on the onset of convection. The Maxwell liquids are found to be more unstable than the one subscribing to the Jeffreys description whereas the Rivlin-Ericksen liquids are comparatively more stable. Rigid-free adiabatic boundary combination is found to give rise to a most stable system, whereas the free isothermal free adiabatic combination gives rise to a most unstable system. (C) 2010 Elsevier Ltd. All rights reserved

Probing Color Octet Couplings at the Large Hadron Collider

Color-octet resonances arise in many well motivated theories beyond the standard model. As colored objects they are produced copiously at the LHC and can be discovered in early searches for new physics in dijet final states. Once they are discovered it will be important to measure the couplings of the new resonances to determine the underlying theoretical structure. We propose a new channel, associated production of $W,Z$ gauge bosons and color-octet resonances, to help determine the chiral structure of the couplings. We present our analysis for a range of color-octet masses (2.5 to 4.5 TeV), couplings and decay widths for the LHC with center of mass energy of 14 TeV and 10 ${\rm fb}^{-1}$ or 100 ${\rm fb}^{-1}$ of integrated luminosity. We find that the LHC can probe a large region of the parameter space up to very small couplings.Comment: 19 pages, 9 figures, 3 table

Unsteady MHD Convective Heat and Mass Transfer of a Casson Fluid Past a Semi-infinite Vertical Permeable Moving Plate with Heat Source/Sink

In this paper, the effects of heat and mass transfer on an unsteady MHD flow of a Casson fluid past a semi-infinite moving vertical plate with heat source/sink are investigated. The governing equations are transformed into a system of linear partial differential equations using appropriate non-dimensional variables. The resulting equations are solved analytically using perturbation technique. Further the expressions for velocity, temperature and concentration are obtained with the help of boundary conditions. Finally the effects of various parameters on velocity, temperature and concentration are shown in graphs.  It is found that velocity increases as Casson parameter increases and temperature increases as heat absorption coefficient decreases. Keywords: Casson parameter, MHD, Heat source/sink, Heat and mass transfer

Resonant Raman of OH/OD vibrations and photoluminescence studies in LiTaO3 thin film

Resonant Raman spectra (RRS) of O-H and O-D vibration and libration modes, their combinations and higher harmonics have been observed in LiTaO3 polycrystalline thin films. RRS peaks are superimposed on photoluminescence (PL) spectrum. Monochromatic light from a xenon lamp is used as excitation source. PL spectrum shows two broad peaks, first near the band gap in UV (4.4-4.8eV) and another in the sub band gap region (< 4.0 eV). Band gap PL along with RRS peaks are reported for the first time. Photoluminescence excitation spectrum (PLE) shows a peak at 4.8 eV. Peak positions and full width at half maximum (FWHM) of RRS peaks depend upon the excitation energy. Dispersions of the fundamental and the third harmonic of the stretching mode of O-H with excitation energy are about 800 cm-1/eV and 2000 cm-1/eV respectively. This dispersion is much higher than reported in any other material.Comment: 20 page