A5075898669- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Nuclear physics research studies
- Particle physics theoretical and experimental studies
- Radioactive Decay and Measurement Techniques
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- Astro and Planetary Science
- Astronomical and nuclear sciences
- Graphite, nuclear technology, radiation studies
- Radioactivity and Radon Measurements
- Experimental and Theoretical Physics Studies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Geophysics and Gravity Measurements
- Color Science and Applications
- Advanced MRI Techniques and Applications
- Pulsars and Gravitational Waves Research
- Analytical Chemistry and Sensors
DePauw University
2005-2024
Tulane University
2005-2021
University of Notre Dame
1999-2008
Hamilton College
2005
Indiana University Bloomington
1992-2005
Harvard University
2005
National Institute of Standards and Technology
2004-2005
Kurchatov Institute
2005
University of Sussex
2005
Rutherford Appleton Laboratory
2005
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...
The $\ensuremath{\beta}$-delayed $\ensuremath{\alpha}$ spectrum from the decay of ${}^{8}\mathrm{B}$ has been measured with a setup that minimized systematic uncertainties affected previous measurements. Consequently deduced neutrino presents much smaller than recommendation [J. N. Bahcall et al., Phys. Rev. C 54, 411 (1996)]. $\ensuremath{\nu}$ is found to be harder previously recommended about $(10--20)%$ more neutrinos at energies between 12--14 MeV. integrated cross sections...
We report the first result for electron-antineutrino angular correlation ($a$ coefficient) in free neutron $\ensuremath{\beta}$ decay from aCORN experiment. uses a novel method which $a$ coefficient is proportional to an asymmetry proton time of flight events where electron and recoil are detected delayed coincidence. Data presented 15 month run at NIST Center Neutron Research. obtained...
The aCORN experiment measures the neutron-decay electron-antineutrino correlation ($a$ coefficient) using a novel method based on an asymmetry in proton time-of-flight for events where beta electron and recoil are detected delayed coincidence. We report data analysis result from second run at NIST Center Neutron Research, high-flux cold neutron beam new NG-C guide end position:...
We determined the absolute branch of $T=2$ superallowed decay $^{32}\mathrm{Ar}$ by detecting ${\ensuremath{\beta}}^{+}$-delayed protons and \ensuremath{\gamma} decays daughter state. obtain ${b}_{\mathrm{SA}}^{\ensuremath{\beta}}=(22.71\ifmmode\pm\else\textpm\fi{}0.16)%$, which represents first determination a proton to better than 1%. Using this along with previously half-life energy release, we $\mathit{ft}=(1552\ifmmode\pm\else\textpm\fi{}12)$ s for decay. This $\mathit{ft}$ value,...
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 determined the energy of J(pi) = 1/2(+), T 3/2 resonance in 32S(p,p) to be E(p) 3374.7+/-0.8 keV. This disagrees with previously accepted value 3370+/-1 keV by Abbondanno et al. [Nuovo Cimento 70A, 391 (1970)] and solves a problem raised recent observations unexpected deviations from isobaric multiplet mass equation. is also important calibrating beta-delayed proton spectra 33Ar 32Ar, our findings may modify previous conclusions.
We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The employs a novel measurement technique which is converted into proton time-of-flight asymmetry that counted directly, avoiding need for spectroscopy. Details of method, apparatus, detectors, data acquisition, and reduction scheme are presented, along with discussion important systematic effects.
A large parity nonconserving longitudinal analyzing power was discovered in polarized-neutron transmission through Xe. An of 4.3\ifmmode\pm\else\textpm\fi{}0.2% observed a $p$-wave resonance at ${E}_{n}=3.2$ eV. The measurement performed with liquid Xe target natural isotopic abundance that placed the polarized epithermal neutron beam, flight path 2, Manuel Lujan Neutron Science Center. This apparatus constructed by TRIPLE Collaboration, and has been used for studies symmetry compound...
In the $\mathrm{UCN}\ensuremath{\tau}$ experiment, ultracold neutrons (UCN) are confined by magnetic fields and Earth's gravitational field. Field-trapping mitigates problem of UCN loss on material surfaces, which caused largest correction in prior neutron experiments using bottles. However, dynamics field traps differ qualitatively from those latter case, bounce off surfaces with significant diffusivity population quickly reaches a static spatial distribution density gradient induced...
The neutron is the simplest nuclear system that can be used to probe structure of weak interaction and search for physics beyond standard model. Measurements lifetime β-decay correlation coefficients with precisions 0.02% 0.1%, respectively, would allow stringent constraints on new physics. UCNτ experiment uses an asymmetric magneto-gravitational UCN trap in situ counting surviving neutrons measure lifetime, τ n = 877.7s (0.7s) stat (+0.4/−0.2s) sys . We discuss recent result from UCNτ,...
The past two decades have yielded several new measurements and reanalyses of older the neutron lifetime. These led to a 4.4 standard deviation discrepancy between most precise decay rate producing protons in cold beams lifetime measured storage experiments. Measurements using different techniques are important for investigating whether there unidentified systematic effects any measurements. In this paper we report measurement Los Alamos asymmetric magneto-gravitational trap where surviving...
The aCORN experiment measures the electron-antineutrino correlation $a$ coefficient in free neutron decay. We update previous results [G. Darius et al., Phys. Rev. Lett. 119, 042502 (2017) and M. T. Hassan C 103, 045502 (2021)] to include radiative recoil corrections first order, discuss a key issue comparison of from different $a$-coefficient experimental methods when these effects are considered. corrected combined result is...
Here we publish three years of data for the UCNtau experiment performed at Los Alamos Ultra Cold Neutron Facility Science Center. These are in addition to our previously published data. Our goals this paper better understand and quantify systematic uncertainties improve lifetime statistical precision. We report a measured value these runs from 2020-2022 neutron 877.94+/-0.37 s; when all averaged an updated 877.82+/-0.22 (statistical)+0.20-0.17 (systematic) s. utilized improved monitor...
The aCORN experiment uses a novel asymmetry method to measure the electron-antineutrino correlation ( -coefficient) in free neutron decay that does not require precision proton spectroscopy. completed two physics runs at NIST Center for Neutron Research. first run on NG-6 beam line obtained result = 0.1090 +/- 0.0030 stat ) 0.0028 (sys), most precise date. second new NG-C high flux promises an improvement ¡ 2%. In addition we show improved measurement of neutrino B can be made using...
Fundamental neutron physics, combining precision measurements and theory, probes particle physics at short range with reach well beyond the highest energies probed by LHC. Significant US efforts are underway that will probe BSM CP violation orders of magnitude more sensitivity, provide new data on Cabibbo anomaly, precisely measure lifetime decay, explore hadronic parity violation. World-leading results from Neutron Physics community since last Long Range Plan, include world's most precise...