A5072960930- Nuclear physics research studies
- Gamma-ray bursts and supernovae
- Astronomical and nuclear sciences
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Neutrino Physics Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Insurance, Mortality, Demography, Risk Management
- High-Energy Particle Collisions Research
- Radioactive Decay and Measurement Techniques
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- Particle accelerators and beam dynamics
- Dark Matter and Cosmic Phenomena
- Advanced Power Generation Technologies
- Rare-earth and actinide compounds
- Radiation Detection and Scintillator Technologies
- Radiopharmaceutical Chemistry and Applications
- Iron and Steelmaking Processes
- Canadian Identity and History
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
TRIUMF
2022-2024
University of Notre Dame
2018-2022
Joint Institute for Nuclear Astrophysics
2020
Notre Dame of Dadiangas University
2020
University of Wisconsin–Madison
2014-2015
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....
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...
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...
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...
Abstract Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand engines astronomical objects origin chemical elements. This white paper summarizes progress status field, new open questions that have emerged, tremendous scientific opportunities opened up with major advances in capabilities across an ever growing number disciplines subfields need be integrated. We take holistic view discussing unique challenges regards science,...
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...
Astrophysical observations of the cosmos allow us to probe extreme physics and answer foundational questions on our universe. Modern astronomy is increasingly operating under a holistic approach, probing same question with multiple diagnostics including how sources vary over time, they appear across electromagnetic spectrum, through their other signatures, gravitational waves, neutrinos, cosmic rays, dust Earth. are now reaching point where approximate models insufficient. Key interest...
The rapid-neutron-capture ("r") process is responsible for synthesizing many of the heavy elements observed in both solar system and Galactic metal-poor halo stars. Simulations r-process nucleosynthesis can reproduce abundances derived from observations with varying success, but so far fail to account over-enhancement actinides, present about 30% r-process-enhanced In this work, we investigate actinide production dynamical ejecta a neutron star merger explore if levels richness boost. We...
A nuclear mass survey of rare-earth isotopes has been conducted with the Canadian Penning Trap spectrometer using most neutron-rich nuclei thus far extracted from CARIBU facility. We present a collection 12 masses determined precision $\ensuremath{\le}10$ keV/$c{}^{2}$ for $Z=58--63$ near $N=100$. Independently, detailed study exploring role in formation $r$-process abundance peak performed. Employing Markov chain Monte Carlo (MCMC) technique, predictions lanthanide have made which uniquely...
Abstract We present new observational benchmarks of rapid neutron-capture process ( r -process) nucleosynthesis for elements at and between the first A ∼ 80) second 130) peaks. Our analysis is based on archival ultraviolet optical spectroscopy eight metal-poor stars with Se Z = 34) or Te 52) detections, whose -process enhancement varies by more than a factor 30 (−0.22 ≤ [Eu/Fe] +1.32). calculate ratios among abundances Se, Sr through Mo (38 42), Te. These may offer empirical alternative to...
We demonstrate that the well-known 2.6 MeV gamma-ray emission line from thallium-208 could serve as a real-time indicator of astrophysical heavy element production, with both rapid ($r$) and intermediate ($i$) neutron capture processes capable its synthesis. consider $r$ process in Galactic star merger show Tl-208 to be detectable $\ensuremath{\sim}12$ hours $\ensuremath{\sim}\mathrm{ten}$ days, again $\ensuremath{\sim}1--20\text{ }\text{ }\mathrm{years}$ postevent. Detection represents only...
Abstract The simulation of heavy element nucleosynthesis requires input from yet-to-be-measured nuclear properties. uncertainty in the values these off-stability properties propagates to uncertainties predictions elemental and isotopic abundances. However, for any given astrophysical explosion, there are many different trajectories, i.e., temperature density histories, experienced by outflowing material, thus can come into play. We consider combined results 460,000 trajectories a black hole...
Since most of the neutrino parameters are well-measured, we illustrate precisely prediction Standard Model, minimally extended to allow massive neutrinos, for electron magnetic moment. We elaborate on effects light sterile neutrinos effective moment measured at reactors. explicitly show that kinematical masses negligible even neutrinos.
We examine the physics of early universe when Majorana neutrinos (${\ensuremath{\nu}}_{e}$, ${\ensuremath{\nu}}_{\ensuremath{\mu}}$, ${\ensuremath{\nu}}_{\ensuremath{\tau}}$) possess transition magnetic moments. These extra couplings beyond usual weak interaction alter way decouple from plasma electrons/positrons and photons. calculate how moment modify neutrino decoupling temperatures, then use a full weak, strong, electromagnetic reaction network to compute corresponding changes in big...
Neutron star mergers (NSMs) are the first verified sites of rapid neutron capture (r-process) nucleosynthesis, and could emit gamma rays from radioactive isotopes synthesized in neutron-rich ejecta. These MeV may provide a unique direct probe NSM environment as well insight into nature r process, just observed gammas 56Ni decay chain window supernova nucleosynthesis. In this work, we include photons fission processes for time estimates gamma-ray signal expected an event. We consider ejecta...
Abstract Merging neutron stars produce “kilonovae”—electromagnetic transients powered by the decay of unstable nuclei synthesized via rapid capture (the r -process) in material that is gravitationally unbound during inspiral and coalescence. Kilonova emission, if accurately interpreted, can be used to characterize masses compositions merger-driven outflows, helping resolve a long-standing debate about origins -process Universe. We explore how uncertain properties involved complicate...
Abstract Lanthanide element signatures are key to understanding many astrophysical observables, from merger kilonova light curves stellar and solar abundances. To learn about the lanthanide synthesis that enriched our system, we apply statistical method of Markov Chain Monte Carlo examine nuclear masses capable forming r -process rare-earth abundance peak. We describe physical constraints implement with this approach demonstrate use parallel chains explore multidimensional parameter space....
Abstract Measuring neutron capture cross sections of radioactive nuclei is a crucial step towards better understanding the origin elements heavier than iron. For decades, precise measurement direct in “stellar” energy range (eV up to few MeV) was limited stable and longer-lived that could be provided as physical samples then irradiated with neutrons. New experimental methods are now being developed extend these measurements shorter-lived ( $$t_{1/2}<$$ <mml:math...
We apply for the first time fission yields determined across chart of nuclides from macroscopic-microscopic theory Finite Range Liquid Drop Model to simulations rapid neutron capture ($r$-process) nucleosynthesis. With rates and derived within same theoretical framework utilized other relevant nuclear data, our results represent an important step toward self-consistent applications models in $r$-process calculations. The this model are wide nuclei with extreme excess. show that these...
Abstract Neutron star mergers (NSMs) are rapid neutron-capture ( r -process) nucleosynthesis sites that expel matter at high velocities, from 0.1 c to as 0.6 . Nuclei ejected these speeds sufficiently energetic initiate spallation nuclear reactions with interstellar medium (ISM) particles. We adopt a thick-target model for the propagation of high-speed heavy nuclei in ISM, similar transport cosmic rays. find may create observable perturbations NSM isotopic abundances, particularly around...
Recently, analysis of the optical counterpart AT2017gfo to gravitational wave-detected neutron star merger GW170817 has suggested a promising resolution long-standing debate on mergers as source some heaviest elements. However, making quantitative progress in these areas requires an accounting uncertainties different aspects physics, which is input into simulations merging compact objects and their associated phenomena, remarkably rapid capture nucleosynthesis. We investigate from nuclear...
Abstract Of the variations in elemental abundance patterns of stars enhanced with r -process elements, variation relative actinide-to-lanthanide ratio is among most significant. We investigate source these actinide differences order to determine whether are due natural astrophysical sites, or uncertain nuclear properties that accessed sites. find between stellar abundances likely nature, owing how neutron-rich ejecta from an event may be. Furthermore, if site capable generating...