Constraining Extra Neutral Gauge Bosons with Atomic Parity Violation Measurements

The discovery of a new neutral gauge boson, $Z'$, could provide the first concrete evidence of physics beyond the standard model. We explore how nuclear weak charge measurements in atomic parity violation (APV) experiments can be used to constrain $Z'$ bosons. We use the recent measurement of the $^{133}$Cs nuclear weak charge to estimate lower bounds on the mass of $Z'$ bosons for a number of representative models and to put constraints on the couplings of a newly discovered $Z'$ boson. We also consider how these constraints might be improved by future APV experiments that will measure nuclear weak charges of multiple isotopes. We show how measurements of a single isotope, and combining measurements into ratios and differences, can be used to constrain the couplings of a $Z'$ and discriminate between models. We find that current and future APV experiments could potentially play an important role in unravelling new physics if a $Z'$ were discovered.Comment: 7 pages, 1 figure, Revised versio

Quartz crystal microbalance use in biological studies

Design, development, and applications of quartz crystal microbalance are discussed. Two types of crystals are used. One serves as reference and other senses changes in mass. Specific application to study of bacterial spores is described

Orbiter/External Tank Mate 3-D Solid Modeling

This research and development project presents an overview of the work completed while attending a summer 2004 American Society of Engineering Education/National Aeronautics and Space Administration (ASEE/NASA) Faculty Fellowship. This fellowship was completed at the Kennedy Space Center, Florida. The scope of the project was to complete parts, assemblies, and drawings that could be used by Ground Support Equipment (GSE) personnel to simulate situations and scenarios commonplace to the space shuttle Orbiter/External Tank (ET) Mate (50004). This mate takes place in the Vehicle Assembly Building (VAB). These simulations could then be used by NASA engineers as decision-making tools. During the summer of 2004, parts were created that defined the Orbiter/ET structural interfaces. Emphasis was placed upon assemblies that included the Orbiter/ET forward attachment (EO-1), aft left thrust strut (EO-2), aft right tripod support structure (EO-3), and crossbeam and aft feedline/umbilical supports. These assemblies are used to attach the Orbiter to the ET. The Orbiter/ET Mate assembly was then used to compare and analyze clearance distances using different Orbiter hang angles. It was found that a 30-minute arc angle change in Orbiter hang angle affected distance at the bipod strut to Orbiter yoke fitting 8.11 inches. A 3-D solid model library was established as a result of this project. This library contains parts, assemblies, and drawings translated into several formats. This library contains a collection of the following files: sti for sterolithography, stp for neutral file work, shrinkwrap for compression. tiff for photoshop work, jpeg for Internet use, and prt and asm for Pro/Engineer use. This library was made available to NASA engineers so that they could access its contents to make angle, load, and clearance analysis studies. These decision-making tools may be used by Pro/Engineer users and non-users

LOFAR observations of 4C+19.44. On the discovery of low frequency spectral curvature in relativistic jet knots

We present the first LOFAR observations of the radio jet in the quasar 4C+19.44 (a.k.a. PKS 1354+19) obtained with the long baselines. The achieved resolution is very well matched to that of archival Jansky Very Large Array (JVLA) observations at higher radio frequencies as well as the archival X-ray images obtained with {\it Chandra}. We found that, for several knots along the jet, the radio flux densities measured at hundreds of MHz lie well below the values estimated by extrapolating the GHz spectra. This clearly indicates the presence of spectral curvature. Radio spectral curvature has been already observed in different source classes and/or extended radio structures and it has been often interpreted as due to intrinsic processes, as a curved particle energy distribution, rather than absorption mechanisms ({ Razin-Tsytovich} effect, free-free or synchrotron self absorption to name a few). Here we discuss our results according to the scenario where particles undergo stochastic acceleration mechanisms also in quasar jet knots.Comment: 13 pages, 4 tables, 4 figures, pre-proof version, published on the Astrophysical Journal (Harris, et al. 2019 ApJ, 873, 21

Splitting of the pi - rho spectrum in a renormalized light-cone QCD-inspired model

We show that the splitting between the light pseudo-scalar and vector meson states is due to the strong short-range attraction in the ^1S_0 sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudo-scalar ground state mass fixes the renormalized strength of the Dirac-delta interaction.Comment: 9 pages, 2 figures, revtex, accepted by Phys. Rev. D; Corrected typo

The running mass msm_s at low scalefrom the heavy-light meson decay constants

It is shown that a 25(20)% difference between the decay constants $f_{D_s}(f_{B_s})$ and $f_D(f_B)$ occurs due to large differences in the pole masses of the $s$ and $d(u)$ quarks. The values $\eta_D =f_{D_s}/f_D\approx 1.23(15)$, recently observed in the CLEO experiment, and $\eta_B=f_{B_s}/f_B\approx 1.20$, obtained in unquenched lattice QCD, can be reached only if the running mass $m_s$ at low scale is $m_s(\sim 0.5$ GeV)$= 170 - 200$ MeV. Our results follow from the analytical expression for the pseudoscalar decay constant $f_{\rm P}$ based on the path-integral representation of the meson Green's function.Comment: 6 pages, no figures; revtex