Constraints on Minute-Scale Transient Astrophysical Neutrino Sources
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79 ASTRONOMY AND ASTROPHYSICS↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Carbon ionization at gigabar pressures: An ab initio perspective on astrophysical high-density plasmas
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Physical Systems↗
From Existing and New Nuclear and Astrophysical Constraints to Stringent Limits on the Equation of State of Neutron-Rich Dense Matter
Through continuous progress in nuclear theory and experiment and an increasing number of neutron-star (NS) observations, a multitude of information about the equation of state (EOS) for matter at extreme densities is available. To constrain the EOS across its entire density range, this information needs to be combined consistently. However, the impact and model dependency of individual observations vary. Given their growing number, assessing the various methods is crucial to compare the respective effects on the EOS and discover potential biases. For this purpose, we present a broad compendium of different constraints and apply them individually to a large set of EOS candidates within a Bayesian framework. Specifically, we explore different ways of how chiral effective field theory and perturbative quantum chromodynamics can be used to place a likelihood on EOS candidates. We also investigate the impact of nuclear experimental constraints, as well as different radio and x-ray observations of NS masses and radii. This is augmented by reanalyses of the existing data from binary neutron star coalescences, in particular of GW170817, with improved models for the tidal waveform and kilonova light curves, which we also utilize to construct a tight upper limit of 2.39 M ⊙ on the TOV mass based on GW170817’s remnant. Our diverse set of constraints is eventually combined to obtain stringent limits on NS properties. We organize the combination in a way to distinguish between constraints where the systematic uncertainties are deemed small and those that rely on less conservative assumptions. For the former, we find the radius of the canonical 1.4 M ⊙ neutron star to be R 1.4 = 12.2 6 − 0.91 + 0.80 km and the TOV mass at M TOV = 2.2 5 − 0.22 + 0.42 M ⊙ (95% credibility). Including all the presented constraints yields R 1.4 = 12.2 0 − 0.48 + 0.50 km and M TOV = 2.3 0 − 0.20 + 0.07 M ⊙ . When comparing these limits to individual data points, we find that the quoted radius of HESS J1731-347 displays noticeable tension with other constraints. Constraining microphysical properties of the EOS proves more challenging. For instance, the symmetry energy slope is restricted to L sym = 48 − 25 + 21 MeV , where this constraint is mainly dominated by our reanalysis of the PREX-II and CREX experiment. Published by the American Physical Society 2025
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Partial-wave analysis for elastic p{sup 13}C scattering at astrophysical energies
A standard partial-wave analysis was performed on the basis of known measurements of differential cross sections for elastic p{sup 13}C scattering at energies in the range 250-750 keV. This analysis revealed that, in the energy range being considered, it is sufficient to take into account the {sup 3}S{sub 1} wave alone. A potential for the triplet {sup 3}S{sub 1}-wave state of the p{sup 13}C system in the region of the J{sup p}T = 1{sup -1} resonance at 0.55 MeV was constructed on the basis of the phase shifts obtained from the aforementioned partial-wave analysis.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Radiative neutron capture by {sup 2}H, {sup 7}Li, {sup 14}C, and {sup 14}N nuclei at astrophysical energies
The possibility of describing experimental data on the total cross sections for the n{sup 2}H, n{sup 7}Li, n{sup 14}C, and n{sup 14}N radiative-capture processes within the potential cluster model involving forbidden states and their classification according to Young's tableaux is considered. It is shown that this model and the methods used here to construct potentials make it possible to describe correctly the behavior of the experimental cross sections at energies between 5 to 10 meV (5 Multiplication-Sign 10{sup -3}-10 Multiplication-Sign 10{sup -3} eV) and 1 to 15MeV.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Study of the (p, γ) and (α, γ) reactions for {sup 96,98,104}Ru and {sup 112,114,116}Sn at astrophysically relevant energies
Cross section and S factor of the proton- and alpha-induced reactions have been studied for the Ruthenium and tin isotopes in the effective energy range, i.e. Gamow window. These reactions are important for developing the understanding for nucleosynthesis, particularly for the synthesis of p nuclei (p process). In this work, cross sections and S factor have been calculated through TALYS in Hauser–Feshbach formalism using nuclear densities calculated in relativistic mean field (RMF) formalism. Calculated results of cross sections, S factor and nuclear structure have been compared with existing theoretical as well as experimental results available and are found to be in good agreement.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Large-volume detector at the Baksan Neutrino Observatory for studies of natural neutrino fluxes for purposes of geo- and astrophysics
At the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow) deployed in the Caucasus mountains, it is proposed to create, at a depth corresponding to 4760 mwe, a large-volume neutrino detector on the basis of a liquid scintillator with a target mass of 10 kt. The detector in question is intended for recording natural fluxes of neutrinos whose energy may be as low as 100MeV. Neutrino fluxes from various sources are considered in the present study, and the expected effect in the proposed detector is estimated. The detector hat is being developed at the Baksan Neutrino Observatorywill become part of the world network of neutrino detectors for studying natural neutrino fluxes.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Large-Volume Detector at the Baksan Neutrino Observatory for Studies of Natural Low-Energy Neutrinos as Geo- and Astrophysical Probes
Constructing a large-volume detector filled with 10 kt of liquid scintillator is envisaged at the Baksan Neutrino Observatory in the Caucasus. This is aimed at detecting fluxes of natural neutrinos with energies up to 100 MeV. The predicted fluxes of such neutrinos and the response of the proposed detector are discussed. This facility is conceived as an integral part of the worldwide net of neutrino detectors aimed at measuring the natural neutrino fluxes.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Covariant Density Functional Theory in Nuclear Physics and Astrophysics
How does subatomic matter organize itself? Neutron stars are cosmic laboratories uniquely poised to answer this fundamental question that lies at the heart of nuclear science. Newly commissioned rare isotope facilities, telescopes operating across the entire electromagnetic spectrum, and ever more sensitive gravitational wave detectors will probe the properties of neutron-rich matter with unprecedented precision over an enormous range of densities. A coordinated effort between observation, experiment, and theoretical research is of paramount importance for realizing the full potential of these investments. Theoretical nuclear physics provides valuable insights into the properties of neutron-rich matter in regimes that are not presently accessible to experiment or observation. In particular, nuclear density functional theory is likely the only tractable framework that can bridge the entire nuclear landscape by connecting finite nuclei to neutron stars. This compelling connection is the main scope of the present review.
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2012 Aspen Winter Conferences on High Energy and Astrophysics
Aspen Center for Physics Project Summary DE-SC0007313 Budget Period: 1/1/2012 to 12/31/2012 The Hunt for New Particles, from the Alps to the Plains to the Rockies The 2012 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 11 to February 17, 2012. Sixty-seven participants from nine countries, and several universities and national labs attended the workshop titled, The Hunt for New Particles, from the Alps to the Plains to the Rockies. There were 53 formal talks, and a considerable number of informal discussions held during the week. The weeks events included a public lecture-Hunting the Dark Universe given by Neal Weiner from New York University) and attended by 237 members of the public, and a physics cafe geared for high schoolers that is a discussion with physicists conducted by Spencer Chang (University of Oregon), Matthew Reece (Harvard University) and Julia Shelton (Yale University) and attended by 67 locals and visitors. While there were no published proceedings, some of the talks are posted online and can be Googled. The workshop was organized by John Campbell (Fermilab), Patrick Fox (Fermilab), Ivan Furic (University of Florida), Eva Halkiadakis (Rutgers University) and Daniel Whiteson (University of California Irvine). Additional information is available at http://indico.cern.ch/conferenceDisplay.py?confId=143360. Inflationary Theory and its Confrontation with Data in the Planck Era The 2012 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was Inflationary Theory and its Confrontation with Data in the Planck Era. It was held from January 30 to February 4, 2012. The 62 participants came from 7 countries and attended 43 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists from other institutions and countries or due to incipient collaborations. In addition, Shamit Kachru of Stanford University gave a public lecture titled The Small (and Large) Scale Structure of Space-Time.There were 237 members of the general public in attendance. Before the lecture, 65 people attended the physics cafe to discuss the current topic with Matthew Kleban (New York University) and Chao-Lin Kuo (Stanford University). This workshop was organized by Olivier Dore (Jet Propulsion Lab), Fabian Schmidt (Caltech), Leonardo Senatore (Stanford University), and Kendrick Smith (Princeton University).
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Particle Astrophysics Theory Group, CWRU 2013 Final Report on DOE grant.
PI G. Starkman and Co-I H. Mathur report on the past three years of their research at the frontiers of particle physics and cosmology.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Breakup of loosely bound nuclei at intermediate energies for nuclear astrophysics and the development of a position sensitive microstrip detector system and its readout electronics using ASICs technologies
The work performed under this grant has led to the development of a detection system that will be used to measure reaction rates for proton or neutron capture reactions at stellar energies on radioactive ions far from stability. The reaction rates are needed to better understand the physics of nucleosynthesis in explosive stellar processes such as supernovae and x-ray burst events. The radioactive ions will be produced at the Radioactive Ion Beam Facility (RIBF) at RIKEN near Tokyo, Japan. During the course of this work, the group involved in this project has expanded by several institutions in Europe and Japan and now involves collaborators from the U.S., Japan, Hungary, Romania, Germany, Spain, Italy, China, and South Korea. As part of the project, a novel design based on large-area silicon detectors has been built and tested. The work has involved mechanical construction of a special purpose vacuum chamber, with a precision mounting system for the silicon detectors, development of a new ASICs readout system that has applications with a wide variety of silicon detector systems, and the development of a data acquisition system that is integrated into the computer system being used at RIBF. The parts noted above that are needed to carry out the research program are completed and ready for installation. Several approved experiments that will use this system will be carried out in the near future. The experimental work has been delayed due to a large increase in the cost and availability of electrical power for RIBF that occurred following the massive earthquake and tsunami that hit Japan in the spring of 2011. Another component of the research carried out with this grant involved developing the theoretical tools that are required to extract the information from the experiments that is needed to determine the stellar reaction rates. The tools developed through this part of the work will be made freely available for general use.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Astrophysics Summaries for 2015-2016 Institutional Computing Allocations
No abstract provided.
79 ASTRONOMY AND ASTROPHYSICS↗
New Laboratory and Astrophysical Probes of Physics Beyond the Standard Model (Final Technical Report)
The first of these directions centers on new ideas in dark matter detection. As experimental scrutiny narrows the window for new physics at the weak scale, it has become apparent that the solution to the dark matter mystery may not reside there. Theoretical developments such as the hidden sector/valley paradigm have, at the same time, shown that compelling theories of dark matter reside below the weak scale. Searching for dark matter at lower mass scales requires looking beyond the current paradigm of dark matter direct detection based on nuclear recoils. It is the goal of this project to provide new ideas to guide the experimental program looking for light dark matter. I am actively proposing ideas for detecting dark matter as light as a meV, well beyond the current focus of GeV-TeV scale dark matter. Some of the ideas I have proposed, such as superconducting, superfluid, and polar material targets, are actively being developed into experiments. My group will provide the relevant calculations to determine dark matter reach, providing crucial input to experiment on which targets should be developed. We will also provide an effective field theory framework to understand which types of experiments are most sensitive to each interaction type. The second of these directions is on probes of dark matter substructure as a mean to constrain, or observe, models of dark matter. The standard ΛCDM paradigm assumes that the dark matter density perturbations are adiabatic, scale invariant, and produced during inflation. However, many standard models of dark matter will produce modifications of this prediction, such as axion models with symmetry broken below the inflationary scale. Remarkably, we have limited direct measurements of the dark matter clumpiness at mass scales below dwarf galaxies. This allows for the possibility of observing modifications from vanilla ΛCDM due to particle dynamics. In many cases, simulations of dark matter structure in the presence of non-scale invariant fluctu- ations are understudied or completely lacking. I plan to develop both theoretical predictions for small scale structure in models with additional matter power on small scales, as well as observa- tional probes of small scale halos or clumps. One idea I have been recently focused on is pulsar timing, though my group will pursue a variety of lensing and astrometric probes. Lastly, the most risky direction involves spacetime fluctuations from quantum gravity. I showed that if one assumes that metric fluctuations in the Minkowski vacuum, at a surface separating a region in and out of causal contact (which we call a “horizon”), are determined by standard thermodynamic considerations at horizon, these metric fluctuations are large enough to observe in an interferometer with similar sensitivity to LIGO. In a follow-up paper we showed that these assumption holds for the vacuum in AdS/CFT. In future work, I plan to connect this work to recent soft graviton results, to frame this work in a concrete Randall-Sundrum model, and to work out concrete phenomenological predictions from the model. This work unquestionably takes a less trodden path, and works well as part of a well-rounded portfolio of less and more risky ideas. Particle physics is currently at a juncture which requires bold exploration of qualitatively new directions. This proposal outlines some of my plans over the coming years in these directions, leaving room also for surprises.
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Fusion in Space: Nuclear Astrophysics, Neutron Star Mergers, and Accretion Disks [Slides]
Where does stuff come from? Observations of the sun one major way to measure abundances (but there are many others). Stars with not too many heavy elements show an interesting, repeatable pattern, which shows up in our sun too!
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Finding my drumbeat: applying lessons learned from Remo Ruffini to understanding astrophysical transients [Slides]
Lessons Learned: Bandwagon science can miss key physics; Bandwagon scientists cling to their bandwagon, oftentimes denying fundamental physics; and, Better approach: Be aware of the physical limitations of a paradigm. What assumptions have been made? How can this be different in Nature?; Be cognizant of alternative models; Encourage the development of those models; and, Although validation is important, fundamental physics forms the basis for Occam’s razor, not whether a toy model fits the data well.
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The Next Generation of Stellar Astrophysics [Slides]
Abstract not provided.
79 ASTRONOMY AND ASTROPHYSICS↗
Ground and Excited Electronic Structure Analysis of CH Diatomic Molecule and Its Astrophysical Importance [Slides]
Ground and excited PECs and DMCs of CH are reported. The aug-cc-pV6Z basis set is a good accuracy-efficiency compromise to study C-H system. CASSCF results are in reasonable agreement with the experiment. High-level MRCI analysis are vital for reaching for the experimental accuracy.
79 ASTRONOMY AND ASTROPHYSICS↗