Steven Clayton
A5059362402- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Particle physics theoretical and experimental studies
- Cold Atom Physics and Bose-Einstein Condensates
- Neutrino Physics Research
- Magnetic confinement fusion research
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Muon and positron interactions and applications
- Advanced NMR Techniques and Applications
- Quantum Chromodynamics and Particle Interactions
- Magnetic and Electromagnetic Effects
- NMR spectroscopy and applications
- Non-Destructive Testing Techniques
- Nuclear reactor physics and engineering
- Power Transformer Diagnostics and Insulation
- Distributed and Parallel Computing Systems
- Particle accelerators and beam dynamics
- Medical Imaging Techniques and Applications
- Spacecraft and Cryogenic Technologies
- Advanced Sensor Technologies Research
- Advanced MRI Techniques and Applications
Los Alamos National Laboratory
2015-2024
California Institute of Technology
2020-2021
Indiana University Bloomington
2020-2021
North Carolina State University
2020-2021
Tennessee Technological University
2020-2021
University of Kentucky
2020-2021
East Tennessee State University
2020-2021
Utah State University
2020-2021
University of Illinois Urbana-Champaign
2001-2015
We report an improved measurement of the free neutron lifetime τ_{n} using UCNτ apparatus at Los Alamos Neutron Science Center. count a total approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns 2017 and 2018. extract from three blinded, independent analyses by both pairing long short storage time runs to find set replicate measurements performing global likelihood fit all while self-consistently...
The precise value of the mean neutron lifetime, $\tau_n$, plays an important role in nuclear and particle physics cosmology. It is a key input for predicting ratio protons to helium atoms primordial universe used search new beyond Standard Model physics. There 3.9 standard deviation discrepancy between $\tau_n$ measured by counting decay rate free neutrons beam (887.7 $\pm$ 2.2 s) surviving ultracold stored different storage times material trap (878.5$\pm$0.8 s). experiment described here...
A neutron $\ensuremath{\beta}$-decay asymmetry measurement using polarized ultracold neutrons (UCN) determines the correlation between spin of and momentum decay electron. The authors extract ratio weak axial-vector to vector couplings with reduced uncertainties. This new result from first this UCN contributes a benchmark for lattice QCD calculations possibility improved precision on CKM matrix element ${V}_{u\phantom{\rule{0}{0ex}}d}$ $\ensuremath{\beta}$ decay.
Fornal and Grinstein recently proposed that the discrepancy between two different methods of neutron lifetime measurements, beam bottle methods, can be explained by a previously unobserved dark matter decay mode, $n\ensuremath{\rightarrow}X+\ensuremath{\gamma}$. We perform search for this mode over allowed range energies monoenergetic $\ensuremath{\gamma}$ ray $X$ to matter. A Compton-suppressed high-purity germanium detector is used identify rays from in nickel-phosphorous-coated...
The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing to various experiments, first production based on superthermal process. It recently undergone a major upgrade. This paper describes design performance of upgraded LANL source. Measurements cold spectrum density are presented compared Monte Carlo predictions....
The rate of nuclear muon capture by the proton has been measured using a new technique based on time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. hyperfine singlet ground state μp atom was obtained difference between μ− disappearance and world average for μ+ decay rate, yielding ΛS=725.0±17.4 s−1, induced pseudoscalar coupling nucleon, gP(q2=−0.88m2μ)=7.3±1.1, extracted.Received 16 April...
The MuCap experiment at the Paul Scherrer Institute has measured rate L_S of muon capture from singlet state muonic hydrogen atom to a precision 1%. A beam was stopped in time projection chamber filled with 10-bar, ultra-pure gas. Cylindrical wire chambers and segmented scintillator barrel detected electrons decay. is determined difference between mu- disappearance free decay rate. result based on analysis 1.2 10^10 decays, which we extract = (714.9 +- 5.4(stat) 5.1(syst)) s^-1 derive...
A cryogenic apparatus is described that enables a new experiment, nEDM@SNS, with major improvement in sensitivity compared to the existing limit search for neutron Electric Dipole Moment (EDM). This uses superfluid 4He produce high density of Ultra-Cold Neutrons (UCN) which are contained suitably coated pair measurement cells. The be operated at Spallation Neutron Source Oak Ridge National Laboratory, polarized 3He from an Atomic Beam injected into and transported cells where it serves as...
Static electric dipole moments of nondegenerate systems probe mass scales for physics beyond the Standard Model well those reached directly at high energy colliders. Discrimination between different models, however, requires complementary searches in atomic-molecular-and-optical, nuclear and particle physics. In this report, we discuss current status prospects near future a compelling suite such experiments, along with developments needed encompassing theoretical framework.
A precise measurement of the neutron decay β asymmetry A₀ has been carried out using polarized ultracold neutrons from pulsed spallation source at Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report = -0.119 66±0.000 89{-0.001 40}{+0.001 23}, which determine ratio axial-vector to vector weak coupling nucleon g{A}/g{V}=-1.275 90{-0.004 45}{+0.004 09}.
We present a detailed report of measurement the neutron $\beta$-asymmetry parameter $A_0$, parity-violating angular correlation between spin and decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from pulsed spallation solid deuterium source via transport through 7-T magnetic field. The then transported an adiabatic-fast-passage spin-flipper field region, prior to storage in cylindrical volume situated within 1-T $2 \times 2\pi$ solenoidal...
It has been proposed recently that a previously unobserved neutron decay branch to dark matter particle ($\ensuremath{\chi}$) could account for the discrepancy in lifetime observed experiments use two different measurement techniques. One of possible final states discussed includes single $\ensuremath{\chi}$ along with an ${e}^{+}{e}^{\ensuremath{-}}$ pair. We data from UCNA (Ultracold Neutron Asymmetry) experiment set limits on this channel. Coincident electron-like events are detected...
The mean life of the positive muon has been measured to a precision 11 ppm using low-energy, pulsed beam stopped in ferromagnetic target, which was surrounded by scintillator detector array. result, tau(micro)=2.197 013(24) micros, is excellent agreement with previous world average. new average 019(21) micros determines Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, measurement positive-muon lifetime needed determine nucleon pseudoscalar coupling g(P).
Recent advances in image data proccesing through deep learning allow for new optimization and performance-enhancement schemes radiation detectors imaging hardware. This enables experiments, which includes photon sciences synchrotron X-ray free electron lasers as a subclass, data-endowed artificial intelligence. We give an overview of generation at sources, learning-based methods processing tasks, hardware solutions acceleration. Most existing approaches are trained offline, typically using...
A precise value for the neutron lifetime (about 880 s) is needed nuclear astrophysics predictions of Big-Bang nucleosynthesis and solar neutrino production, as well in precision searches new physics beyond Standard Model. This work reports on a type magnetic trap that has potential to resolve present 4-sigma inconsistency measurements lifetime, suggests next generation with less than one second uncertainty possible.
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the $\beta$-decay asymmetry parameter, $A_0$, for free neutron decay. In experiment, polarized ultracold neutrons are transported into a decay trap, and their electrons detected with $\approx 4\pi$ acceptance two detector packages which provide position energy reconstruction. also has sensitivity $b_{n}$, Fierz interference term in rate. this work, we determine $b_{n}$ from dependence of $A_0$ using data taken during...
We report a study of the intensity and time dependence scintillation produced by weak $\ensuremath{\alpha}$-particle sources in superfluid helium presence an electric field (0--45 kV/cm) temperature range 0.2 to 1.1 K at saturated vapor pressure. Both prompt delayed components exhibit reduction with application field. The component is well approximated linear on strength 15$%$ 45 kV/cm. When analyzed using Kramers theory columnar recombination, this leads conclusion that roughly 40$%$...
Background: The rate \lambda_pp\mu\ characterizes the formation of pp\mu\ molecules in collisions muonic p\mu\ atoms with hydrogen. In measurements basic weak muon capture reaction on proton to determine pseudoscalar coupling g_P, occurs from both atomic and molecular states. Thus knowledge is required for a correct interpretation these experiments. Purpose: Recently MuCap experiment has measured \Lambda_S singlet atom, employing low density active target suppress (PRL 110, 12504 (2013))....
In this paper, we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold (UCN), which provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. An active detector that can be lowered into the trap has been used to measure distribution as function height influence marginally trapped UCN on measurement. addition, have demonstrated phase-space evolution its effect
We have constructed an apparatus to study DC electrical breakdown in liquid helium at temperatures as low 0.4 K and pressures between the saturated vapor pressure ∼600 Torr. The can house a set of electrodes that are 12 cm diameter with gap 1–2 them, potential up ±50 kV be applied each electrode. Initial results demonstrated it is possible apply fields exceeding 100 kV/cm 1 two electropolished stainless steel for wide range K. also measured current electrodes. Our initial results, I <...