A5007785750- Nuclear physics research studies
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Quantum Chromodynamics and Particle Interactions
- Astrophysical Phenomena and Observations
- Radioactive Decay and Measurement Techniques
- Scientific Research and Discoveries
- Particle physics theoretical and experimental studies
- Stellar, planetary, and galactic studies
- Nuclear Materials and Properties
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Planetary Science and Exploration
- Magnetic confinement fusion research
- Geophysics and Gravity Measurements
- Graphite, nuclear technology, radiation studies
- Markov Chains and Monte Carlo Methods
- Radioactive element chemistry and processing
- Radioactivity and Radon Measurements
Los Alamos National Laboratory
2016-2025
Joint Institute for Nuclear Astrophysics
2015-2023
Michigan State University
2023
University of Notre Dame
2013-2018
Union College
2011-2014
North Carolina State University
2011-2014
Oak Ridge National Laboratory
2011-2014
University of Tennessee at Knoxville
2011-2014
Abstract The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it offer unique opportunities to address many key astrophysical questions in completely novel way. synergy with ground-based and space-born instruments the electromagnetic domain, by enabling multi-messenger observations, add further discovery potential of LISA. next decade is crucial prepare community LISA’s first observations. This review outlines...
The 2017 detection of the inspiral and merger two neutron stars in gravitational waves gamma rays was accompanied by a quickly-reddening transient. Such transient predicted to occur following rapid capture (r-process) nucleosynthesis event, which synthesizes neutron-rich, radioactive nuclei can take place both dynamical ejecta wind driven off accretion torus formed after star merger. We present first three-dimensional general relativistic, full transport neutrino radiation...
This is an exciting time for the study of r-process nucleosynthesis. Recently, a neutron star merger GW170817 was observed in extraordinary detail with gravitational waves and electromagnetic radiation from radio to γ rays. The very red color associated kilonova suggests that mergers are important site. Astrophysical simulations core collapse supernovae making rapid progress. Detection both electron neutrinos antineutrinos next galactic supernova will constrain composition neutrino-driven...
We present calculated fission-barrier heights for 5239 nuclides all nuclei between the proton and neutron drip lines with $171\ensuremath{\le}A\ensuremath{\le}330$. The barriers are in macroscopic-microscopic finite-range liquid-drop model a 2002 set of macroscopic-model parameters. saddle-point energies determined from potential-energy surfaces based on more than 5 000 different shapes, defined by five deformation parameters three-quadratic-surface shape parametrization: elongation, neck...
Some of the heavy elements, such as gold and europium (Eu), are almost exclusively formed by rapid neutron capture process (r-process). However, it is still unclear which astrophysical site between core-collapse supernovae star - (NS-NS) mergers produced most r-process elements in universe. Galactic chemical evolution (GCE) models can test these scenarios quantifying frequency yields required to reproduce amount (Eu) observed galaxies. Although NS-NS have become popular candidates, their (or...
Neutron star mergers offer unique conditions for the creation of heavy elements and additionally provide a testbed our understanding this synthesis known as $r$-process. We have performed dynamical nucleosynthesis calculations identified single isotope, $^{254}$Cf, which has particularly high impact on brightness electromagnetic transients associated with order 15 to 250 days. This is due anomalously long half-life isotope efficiency fission thermalization compared other nuclear channels....
We evaluate the impact of using sets fission yields given by GEF code for spontaneous (sf), neutron-induced ((n,f)), and beta-delayed (betadf) processes which take into account approximate initial excitation energy fissioning compound nucleus. further explore energy-dependent dynamics in r process considering sensitivity our results to treatment sharing de-excitation fragments FREYA code. show that asymmetric-to-symmetric yield trends predicted can reproduce high-mass edge second r-process...
The mergers of binary neutron stars, as well black hole-neutron star systems, are expected to produce an electromagnetic counterpart that can be analyzed infer the element synthesis occurred in these events. We investigate one source uncertainties pertinent lanthanide-rich outflows: nuclear inputs rapid capture nucleosynthesis calculations. begin by examining thirty-two different combinations inputs: eight mass models, two types spontaneous fission rates, and daughter product distributions....
Accurate nuclear data are essential for advances in fields related to energy, security, medicine and space exploration, with similar needs shared by multiple applications. This perspective addresses some of the latest applications suggests work ensure both near- long-term progress
The rapid neutron capture or 'r process' of nucleosynthesis is believed to be responsible for the production approximately half natural abundance heavy elements found on periodic table above iron (with proton number $Z=26$) and all bismuth ($Z=83$). In course creating actinides potentially superheavies, r process must necessarily synthesize superheavy nuclei (those with extreme numbers, numbers both) far from isotopes accessible in laboratory. Many questions about this remain unanswered,...
We have performed for the first time a comprehensive study of sensitivity $r$-process nucleosynthesis to individual nuclear masses across chart nuclides. Using latest version (2012) Finite-Range Droplet Model, we consider mass variations $\ifmmode\pm\else\textpm\fi{}0.5$ MeV and propagate each change all affected quantities, including $Q$ values, reaction rates, branching ratios. find such can result in up an order magnitude local final abundance pattern produced simulation. identify key...
We study the formation and final structure of rare earth peak ($A\sim160$) $r$-process nucleosynthesis. The forms at late times in after neutron exhaustion (neutron-to-seed ratio unity or R=1) as matter decays back to stability. Since does not occur during \nggn \ equilibrium it is sensitive strong interplay between time thermodynamic evolution nuclear physics input. Depending on conditions either because pattern capture rates separation energies. analyze three mass models under different...
We present $\beta$-delayed neutron emission and fission calculations for heavy, neutron-rich nuclei using the coupled Quasi-Particle Random Phase Approximation plus Hauser-Feshbach (QRPA+HF) approach. From initial population of a compound nucleus after $\beta$-decay, we follow statistical decay taking into account competition between neutrons, $\gamma$-rays, fission. find region chart nuclides where probability is $\sim100$%, that likely prevents production superheavy elements in nature. For...
We model a compact black hole-accretion disk system in the collapsar scenario with full transport, frequency dependent, general relativistic radiation magnetohydrodynamics. examine whether or not winds from can undergo rapid neutron capture (r-process) nucleosynthesis and significantly contribute to solar r-process abundances. find inclusion of accurate transport has significant effects on outflows, raising electron fraction above $Y_{\rm e} \sim 0.3$ preventing third peak material being...
Nuclear reactions where an exotic nucleus captures a neutron are critical for wide variety of applications, from energy production and national security, to astrophysical processes, nucleosynthesis. Neutron capture rates well constrained near stable isotopes experimental data available; however, moving far the valley stability, uncertainties grow by orders magnitude. This is due complete lack constraints, as direct measurement neutron-capture reaction on short-lived extremely challenging....
The Canadian Penning Trap mass spectrometer at the Californium Rare Isotope Breeder Upgrade (CARIBU) facility was used to measure masses of eight neutron-rich isotopes Nd and Sm. These measurements are first push into region nuclear relevant formation rare-earth abundance peak $A\ensuremath{\sim}165$ by rapid neutron-capture process. We compare our results with theoretical predictions obtained from ``reverse engineering'' surface that best reproduces observed solar abundances in this through...
We have calculated a complete set of primary fission fragment mass yields, $Y(A)$, for heavy nuclei across the chart nuclides, including those particular relevance to rapid neutron capture process ($r$ process) nucleosynthesis. assume that nuclear shape dynamics are strongly damped which allows description via Brownian motion potential-energy surfaces. The macroscopic energy potential was obtained with Finite-Range Liquid-Drop Model (FRLDM), while microscopic terms were extracted from...
The composition of the early Solar System can be inferred from meteorites. Many elements heavier than iron were formed by rapid neutron-capture process (r process), but astrophysical sources where this occurred remain poorly understood. We demonstrate that near-identical half-lives ($\simeq$ 15.6 Myr) radioactive r-process nuclei 129I and 247Cm preserve their ratio, irrespective time between production incorporation into System. constrain last source comparing measured meteoritic / = 438...
Machine learning methods and uncertainty quantification have been gaining interest throughout the last several years in low-energy nuclear physics. In particular, Gaussian processes Bayesian Neural Networks increasingly applied to improve mass model predictions while providing well-quantified uncertainties. this work, we use probabilistic Mixture Density Network (MDN) directly predict excess of 2016 Atomic Mass Evaluation within range measured data, extrapolate inferred models beyond...
We present an approach to modeling the ground-state mass of atomic nuclei based directly on a probabilistic neural network constrained by relevant physics. Our physically interpretable machine learning (PIML) incorporates knowledge physics using motivated feature space in addition soft constraint that is implemented as penalty loss function. train our PIML model random set approximately 20% evaluation (AME) and predict remaining 80%. The success methodology exhibited...
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. r-process production of heavier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments, so must be extrapolated using nucleosynthesis models. We examine element abundances in a sample stars that enhanced elements. Ru, Rh, Pd, Ag (atomic numbers Z = 44 47, mass A 99 110) correlate with those (63 <= 78, > 150). There...
The rapid neutron capture process (r-process) is one of the main mechanisms whereby elements heavier than iron are synthesized, and entirely responsible for natural production actinides. Kilonova emissions modeled as being largely powered by radioactive decay species synthesized via r -process. Given that -process occurs far from nuclear stability, unmeasured beta rates play an essential role in setting time scale In effort to better understand sensitivity kilonova modeling different...
Abstract We simulate a black hole accretion disk system with full-transport general relativistic neutrino radiation magnetohydrodynamics for 1.2 s. This is likely to form after the merger of two compact objects and thought be robust site r -process nucleosynthesis. consider case arising from neutron stars. Our simulation time coincides nucleosynthesis timescale (∼1 s). Because these simulations are time-consuming, it common practice run “short” duration approximately 0.1–0.3 analyze...