We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor νover ¯_{e} inverse β decay candidates observed over 1958 days ...of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative νover ¯_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3} eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3} eV^{2} assuming the inverted hierarchy.
On the properties of qudits Balantekin, A. B.; Suliga, Anna M.
The European physical journal. A, Hadrons and nuclei,
06/2024, Volume:
60, Issue:
6
Journal Article
Peer reviewed
Open access
Motivated by the growing interest in the applications of quantum information science in astrophysical settings, especially for the neutrino transport in compact objects where three-flavors of ...neutrinos need to be mapped on qutrits, we review properties of one- and two-qudit systems. We contrast two-qubit and two-qudit systems by pointing out how some of the properties of two-qubit systems generalize to higher dimensions and explore emerging new properties for dimensions three or higher. One example is provided by the Werner states: when the density operator is written in the fundamental representation, we show that only two-qubit Werner states can be pure states, but not two-qudit Werner states when the qudit dimension is larger than two.
Current status of r-process nucleosynthesis Kajino, T.; Aoki, W.; Balantekin, A.B. ...
Progress in particle and nuclear physics,
July 2019, 2019-07-00, 2019-07-01, Volume:
107, Issue:
C
Journal Article
Peer reviewed
The rapid neutron capture process (r process) is believed to be responsible for about half of the production of the elements heavier than iron and contributes to abundances of some lighter nuclides ...as well. A universal pattern of r-process element abundances is observed in some metal-poor stars of the Galactic halo. This suggests that a well-regulated combination of astrophysical conditions and nuclear physics conspires to produce such a universal abundance pattern. The search for the astrophysical site for r-process nucleosynthesis has stimulated interdisciplinary research for more than six decades. There is currently much enthusiasm surrounding evidence for r-process nucleosynthesis in binary neutron star mergers in the multi-wavelength follow-up observations of kilonova/gravitational-wave GRB170807A/GW170817. Nevertheless, there remain questions as to the contribution over the history of the Galaxy to the current solar-system r-process abundances from other sites such as neutrino-driven winds or magnetohydrodynamical ejection of material from core-collapse supernovae. In this review we highlight some current issues surrounding the nuclear physics input, astronomical observations, galactic chemical evolution, and theoretical simulations of r-process astrophysical environments with the goal of outlining a path toward resolving the remaining mysteries of the r process.
.
Short-baseline reactor neutrino experiments successfully measured the neutrino parameters they set out to measure, but they also identified a shape distortion in the 5-7 MeV range as well as a ...reduction from the predicted value of the flux. Nuclear physics input into the calculations of reactor antineutrino spectra needs to be better refined if this anomaly is to be interpreted as due to sterile neutrino states.
Context.
Pulsational pair-instability supernovae (PPISNe) and pair instability supernovae (PISNe) are the result of a thermonuclear runaway in the presence of a background electron-positron pair ...plasma. As such, their evolution and resultant black hole masses could possibly be affected by screening corrections due to the electron pair plasma.
Aims.
The sensitivity of PISNe and PPISNe to relativistic weak screening has been explored.
Methods.
In this paper a weak screening model that includes effects from relativistic pair production has been developed and applied at temperatures approaching and exceeding the threshold for pair production. This screening model replaces “classical” screening commonly used in astrophysics. Modifications to the weak screening electron Debye length were incorporated in a computationally tractable analytic form.
Results.
In PPISNe the BH masses were found to increase somewhat at high temperatures, though this increase is small. The BH collapse is also found to occur at earlier times, and the pulsational morphology also changes. In addition to the resultant BH mass, the sensitivity to the screening model of the pulsational period, the pulse structure, the PPISN-to-PISN transition, and the shift in the BH mass gap has been analyzed. The dependence of the composition of the ejected mass was also examined.
Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter ...presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θμe mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm241, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CLs for Δm241 < 13 eV2. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CLs for Δm241 < 1.6 eV2.
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