A5063621269- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Muon and positron interactions and applications
- Particle accelerators and beam dynamics
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Physics of Superconductivity and Magnetism
- Nuclear physics research studies
- Magnetic confinement fusion research
- Advancements in Battery Materials
- Geophysics and Sensor Technology
- Experimental and Theoretical Physics Studies
- Computational Physics and Python Applications
- earthquake and tectonic studies
- Quantum, superfluid, helium dynamics
- Plasma Diagnostics and Applications
- Particle physics theoretical and experimental studies
- Scientific Research and Discoveries
- Astrophysics and Cosmic Phenomena
Western Washington University
2022-2025
University of Washington
2011-2020
Max Planck Institute for Nuclear Physics
2004-2011
Max Planck Society
2004-2007
We tested the gravitational $1/r^2$ law using a stationary torsion-balance detector and rotating attractor containing test bodies with both 18-fold 120-fold azimuthal symmetries that simultaneously tests at two different length scales. took data detector-attractor separations between $52~\mu$m 3.0 mm. Newtonian gravity gave an excellent fit to our data, limiting 95\% confidence any gravitational-strength Yukawa interactions ranges $< 38.6~\mu$m.
Low mass pseudoscalars, such as the axion, can mediate macroscopic parity and time-reversal symmetry-violating forces. We searched for a force between polarized electrons unpolarized atoms using novel, magnetically unshielded torsion pendulum. improved laboratory bounds on this by more than 10 orders of magnitude pseudoscalars heavier 1 meV have constrained over broad range astrophysically interesting masses (10 μeV to meV).
A new determination of the decay rate negative ion positronium (Ps-), using a beam-foil method and stripping-based detection technique, is reported. The measured result gamma = 2.089(15) ns(-1) factor 6 more precise than previous experimental value 2.09(9) ns(-1), in excellent agreement with theoretical 2.086(6) ns(-1).
The negative positronium ion Ps${}^{\ensuremath{-}}$ is a bound system consisting of two electrons and positron. Its three constituents are pointlike leptonic particles equal mass, which subject only to the electroweak gravitational force. Hence, an ideal object in study quantum mechanics three-body system. ground state stable against dissociation but unstable annihilation into photons. We report here on precise measurement ground-state decay rate $\ensuremath{\Gamma}$, was carried out at...
A great number of theoretical papers have been published dealing with the negative positronium ion Ps . On other hand, experimental data on this purely leptonic three-body system (e + e ) is very limited. Apart from a first observation, lifetime measurement an accuracy 4% has published. We built set-up to produce making use moderated positrons 22 Na source, and we are presently running experiment improve its decay rate. This paper discusses status project as well possibilities extending...
The negative positronium (Ps – ) ion consisting of two electrons and a positron (e + e ), represents the simplest three-body system with bound state. Its constituents are stable, point-like particles, it is essentially free from perturbations by strong interaction effects. Together rather unique mass ratio, these properties make an interesting object for studying quantum-mechanical problem. We present new determination decay rate Ps , using beam-foil method stripping-based detection...
We searched for violations of the weak equivalence principle using a cryogenic torsion balance with pendulum comprised superconducting niobium and copper. constrain E\"otv\"os parameter 95\%-confidence to $\eta_{\text{Nb*-Cu}}~\leq~2.0\times10^{-9}$ $\eta_{\text{CP-ee}}\leq6.9\times10^{-3}$ Cooper pairs, respectively.
We describe a liquid-cryogen free cryostat with ultra-low vibration levels, which allows for continuous operation of torsion balance at cryogenic temperatures. The apparatus uses commercially available two-stage pulse-tube cooler and passive isolation. exhibits torque noise levels lower than room temperature thermal by factor about four in the frequency range 3-10 mHz, limited residual seismic motion radiative heating pendulum body. In addition to lowering below room-temperature limits,...