A Determination of the Hubble Constant from Cepheid Distances and a Model of the Local Peculiar Velocity Field

We present a measurement of the Hubble Constant based on Cepheid distances to 27 galaxies within 20 Mpc. We take the Cepheid data from published measurements by the Hubble Telescope Key Project on the Distance Scale (H0KP). We calibrate the Cepheid Period-Luminosity (PL) relation with data from over 700 Cepheids in the LMC obtained by the OGLE collaboration; we assume an LMC distance modulus of 18.50 mag (d=50.1 kpc). Using this PL calibration we obtain new distances to the H0KP galaxies. We correct the redshifts of these galaxies for peculiar velocities using two distinct velocity field models: the phenomenological model of Tonry et al. and a model based on the IRAS density field and linear gravitational instability theory. We combine the Cepheid distances with the corrected redshifts for the 27 galaxies to derive H_0, the Hubble constant. The results are H_0 = 85 +/- 5 km/s/Mpc (random error) at 95% confidence when the IRAS model is used, and 92 +/- 5 km/s/Mpc when the phenomenological model is used. The IRAS model is a better fit to the data and the Hubble constant it returns is more reliable. Systematic error stems mainly from LMC distance uncertainty which is not directly addressed by this paper. Our value of H_0 is significantly larger than that quoted by the H0KP, H_0 = 71 +/- 6 km/s/Mpc. Cepheid recalibration explains ~30% of this difference, velocity field analysis accounts for ~70%. We discuss in detail possible reasons for this discrepancy and future study needed to resolve it.Comment: 33 pages, 8 embedded figures. New table, 5 new references, text revision

Z-prime Gauge Bosons at the Tevatron

We study the discovery potential of the Tevatron for a Z-prime gauge boson. We introduce a parametrization of the Z-prime signal which provides a convenient bridge between collider searches and specific Z-prime models. The cross section for p pbar -> Z-prime X -> l^+ l^- X depends primarily on the Z-prime mass and the Z-prime decay branching fraction into leptons times the average square coupling to up and down quarks. If the quark and lepton masses are generated as in the standard model, then the Z-prime bosons accessible at the Tevatron must couple to fermions proportionally to a linear combination of baryon and lepton numbers in order to avoid the limits on Z--Z-prime mixing. More generally, we present several families of U(1) extensions of the standard model that include as special cases many of the Z-prime models discussed in the literature. Typically, the CDF and D0 experiments are expected to probe Z-prime-fermion couplings down to 0.1 for Z-prime masses in the 500--800 GeV range, which in various models would substantially improve the limits set by the LEP experiments.Comment: 34 pages, 13 figure

Analysis of location uncertainty for a microearthquake cluster: A case study

In many reservoirs, an increase in permeability and conductivity is achieved by hydraulic fracturing/stimulations which open cracks and fractures that then act as pathways for fluids to navigate in the subsurface. Mapping, localization, and general characterization of these fracture systems is of key importance in oil, gas, and geothermal energy production. The location of the microseismic events triggered during hydraulic fracturing or stimulation can help to characterize the properties of the fracture system. There are many different methods for localizing microearthquakes and, in general, these methods yield different locations, velocity models, and event origin times, due to differences in algorithms and input models. Here we focus on studying location confidence intervals associated with two localization methods, classical (triangulation) and Double-Difference, where uncertainties due to origin times can be marginalized away, thus decreasing uncertainties in the event locations. We relocate events using these two methods and three different velocity models. Of the two methods used here, Double-Difference produces smallest confidence regions. We also illustrate that, for our dataset in particular, marginalizing away the influence of the unknown origin times also improves the confidence intervals

Supersymmetry phenomenology beyond the MSSM after 5/fb of LHC data

We briefly review the status of motivated beyond-the-MSSM phenomenology in the light of the LHC searches to date. In particular, we discuss the conceptual consequences of the exclusion bounds, of the hint for a Higgs boson at about 125 GeV, and of interpreting the excess of direct CP violation in the charm sector as a signal of New Physics. We try to go into the various topics in a compact way while providing a relatively rich list of references, with particular attention to the most recent developments.Comment: 20 pages + refs. v2: minor modifications, published versio

Multi-Channel Transport in Disordered Medium under Generic Scattering Conditions

Our study of the evolution of transmission eigenvalues, due to changes in various physical parameters in a disordered region of arbitrary dimensions, results in a generalization of the celebrated DMPK equation. The evolution is shown to be governed by a single complexity parameter which implies a deep level of universality of transport phenomena through a wide range of disordered regions. We also find that the interaction among eigenvalues is of many body type that has important consequences for the statistical behavior of transport properties.Comment: 19 Pages, No Figure

Pull-in control in microswitches using acoustic Casimir forces

In this paper we present a theoretical calculation of the acoustic Casimir pressure in a model micro system. Unlike the quantum case, the acoustic Casimir pressure can be made attractive or repulsive depending on the frequency bandwidth of the acoustic noise. As a case study, a one degree of freedom simple-lumped system in an acoustic resonant cavity is considered. We show that the frequency bandwidth of the acoustic field can be tuned to increase the stability in existing microswitch systems by selecting the sign of the force. The acoustic intensity and frequency bandwidth are introduced as two additional control parameters of the microswitch

Features of the fluctuation -electromagnetic interaction between a small conducting particle and polarizable medium

For the first time, new important features of the fluctuation electromagnetic interaction between a small conducting particle and a smooth surface of polarizable medium (both dielectric and metallic) are worked out. The particle is characterized by classical electric and magnetic polarizabilities. The temperature dependence and retardation effects are explicitly taken into account. The resulting interaction force between a metallic particle and the surface of metal proves to be determined to great extent by magnetic coupling and reveals specific dependences on distance, temperature, particle radius and material properties of contacting materials. Numerical estimations are given in the case of a Cu particle above a smooth Cu substrate at different particle radius and temperature of the system.Comment: 13 pages, 5 figure

Naturalness bounds in extensions of the MSSM without a light Higgs boson

Adopting a bottom-up point of view, we make a comparative study of the simplest extensions of the MSSM with extra tree level contributions to the lightest Higgs boson mass. We show to what extent a relatively heavy Higgs boson, up to 200-350 GeV, can be compatible with data and naturalness. The price to pay is that the theory undergoes some change of regime at a relatively low scale. Bounds on these models come from electroweak precision tests and naturalness, which often requires the scale at which the soft terms are generated to be relatively low.Comment: 18 pages, 5 figures. v2: minor revision, added references. v3,v4: some numerical correction

Higgs Mass from D-Terms: a Litmus Test

We explore supersymmetric theories in which the Higgs mass is boosted by the non-decoupling D-terms of an extended $U(1)_X$ gauge symmetry, defined here to be a general linear combination of hypercharge, baryon number, and lepton number. Crucially, the gauge coupling, $g_X$, is bounded from below to accommodate the Higgs mass, while the quarks and leptons are required by gauge invariance to carry non-zero charge under $U(1)_X$. This induces an irreducible rate, $\sigma$BR, for $pp \rightarrow X \rightarrow \ell\ell$ relevant to existing and future resonance searches, and gives rise to higher dimension operators that are stringently constrained by precision electroweak measurements. Combined, these bounds define a maximally allowed region in the space of observables, ($\sigma$BR, $m_X$), outside of which is excluded by naturalness and experimental limits. If natural supersymmetry utilizes non-decoupling D-terms, then the associated $X$ boson can only be observed within this window, providing a model independent `litmus test' for this broad class of scenarios at the LHC. Comparing limits, we find that current LHC results only exclude regions in parameter space which were already disfavored by precision electroweak data.Comment: 7 pages, 9 figure

Minimal Gaugomaly Mediation

Mixed anomaly and gauge mediation ("gaugomaly'' mediation) gives a natural solution to the SUSY flavor problem with a conventional LSP dark matter candidate. We present a minimal version of gaugomaly mediation where the messenger masses arise directly from anomaly mediation, automatically generating a messenger scale of order 50 TeV. We also describe a simple relaxation mechanism that gives rise to realistic mu and B mu terms. B is naturally dominated by the anomaly-mediated contribution from top loops, so the mu/B mu sector only depends on a single new parameter. In the minimal version of this scenario the full SUSY spectrum is determined by two continuous parameters (the anomaly- and gauge-mediated SUSY breaking masses) and one discrete parameter (the number of messengers). We show that these simple models can give realistic spectra with viable dark matter.Comment: 18 pages, 4 figures; v2: corrected example generating non-holomorphic Kahler term