A5050563011- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Radiation Detection and Scintillator Technologies
- Magnetic confinement fusion research
- Particle physics theoretical and experimental studies
- Non-Destructive Testing Techniques
- Superconducting Materials and Applications
- Spacecraft and Cryogenic Technologies
- Advanced Database Systems and Queries
- Particle Detector Development and Performance
- Mathematics, Computing, and Information Processing
- Semantic Web and Ontologies
- Particle accelerators and beam dynamics
- Advanced Sensor Technologies Research
- Wnt/β-catenin signaling in development and cancer
- Library Science and Information Systems
- Magnetic and Electromagnetic Effects
- Fire Detection and Safety Systems
- Advanced MRI Techniques and Applications
- Power Transformer Diagnostics and Insulation
- Nuclear reactor physics and engineering
- Neutrino Physics Research
Los Alamos National Laboratory
2014-2023
Utah State University
2020-2021
North Carolina State University
2020-2021
California Institute of Technology
2020-2021
Tennessee Technological University
2020-2021
University of Kentucky
2020-2021
Indiana University Bloomington
2020-2021
East Tennessee State University
2020-2021
Victorian Infectious Diseases Reference Laboratory
2015
The University of Melbourne
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 mammalian adult small intestinal epithelium is a rapidly self-renewing tissue that maintained by pool of cycling stem cells intermingled with Paneth at the base crypts. These crypt exclusively express Lgr5 and require Wnt3 or, in its absence, Wnt2b. However, Frizzled (Fzd) receptor transmits these Wnt signals unknown. We determined expression profile Fzd receptors Lgr5+ cells, their immediate daughter cells. Here we show Fzd7 enriched binds Conditional deletion gene leads to cell loss...
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.
Activation of beta-catenin/T cell factor (TCF) transcription as a result mutations in the adenomatous polyposis coli (APC) and/or beta-catenin genes occurs majority colon tumors. An increasing number genes, including c-myc and cyclin D1, have been implicated targets this pathway. We now report that dominant negative helix-loop-helix regulator Id2 is also target beta-catenin/TCF pathway adenocarcinoma. Investigation mechanism for overexpression carcinoma cells demonstrated promoter activated,...
A new measurement of the neutron $β$-decay asymmetry $A_0$ has been carried out by UCNA collaboration using polarized ultracold neutrons (UCN) from solid deuterium UCN source at Los Alamos Neutron Science Center (LANSCE). Improvements in experiment have led to reductions both statistical and systematic uncertainties leading $A_0 = -0.11954(55)_{\rm stat.}(98)_{\rm syst.}$, corresponding ratio axial-vector vector coupling $λ\equiv g_A/g_V -1.2756(30)$.
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....
In this paper, we describe the performance of Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements cold flux, very low energy production rate, and UCN rates density at exit from biological shield are presented compared to Monte Carlo predictions. The compare well with predictions code MCNPX agree our custom code. source is shown perform as modeled. maximum delivered 52(9) UCN/cc a solid deuterium volume ∼1500 cm3.
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...
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...
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 the first measurement of an angular correlation parameter in neutron $\ensuremath{\beta}$ decay using polarized ultracold neutrons (UCN). utilize UCN with energies below about 200 neV, which we guide and store for $\ensuremath{\sim}30\text{ }\text{ }\mathrm{s}$ a Cu volume. The interaction magnetic dipole moment static 7 T field external to volume provides 420 neV potential energy barrier spin state parallel field, polarizing before they pass through adiabatic fast passage flipper...
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
Precision measurements of free-neutron β decay have been used to precisely constrain our understanding the weak interaction. However, neutron Fierz interference term bn, which is particularly sensitive beyond-standard-model tensor currents at TeV scale, has thus far eluded measurement. Here we report first direct constraints on this term, finding bn=0.067±0.005stat+0.090−0.061sys, consistent with standard model. The uncertainty dominated by absolute energy reconstruction and linearity...
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 <...
The dependence on applied electric field ($0 - 40$ kV/cm) of the scintillation light produced by fast electrons and $\alpha$ particles stopped in liquid helium temperature range 0.44 K to 3.12 is reported. For both types particles, reduction intensity signal due exhibits an apparent dependence. Using approximate solution Debye-Smoluchowski equation, we show that for can be explained time required geminate pairs recombine relative detector integration time. This finding indicates spatial...