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Deciphering the conditions under which neutron captures occur in the Universe to synthesize heavy elements is an endeavour pursued since the 1950s, but that has proven elusive up to now due to the experimental difficulty of generating the…

Plasma Physics · Physics 2023-12-15 Vojtěch Horný , Sophia N. Chen , Xavier Davoine , Laurent Gremillet , Julien Fuchs

As the early universe expands and cools the rates of the weak interactions that keep neutrinos in thermal equilibrium with the matter and the related rates of the reactions that inter-convert neutrons and protons decrease. Eventually, these…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-31 Evan Grohs , George M. Fuller

We propose a $(p,xn)$ mechanism with dynamic production as a new set of nuclear reactions that could produce high density neutrons and explain the r- and rp-elements. We calculate the rate of thorium and uranium produced by our proposed…

Nuclear Theory · Physics 2020-09-04 Pedro V. Guillaumon , Iuda D. Goldman

A neutron star is born as a hot, lepton-rich protoneutron star (PNS) and cools via neutrino emission, eventually allowing heavy ions in the outer layers to crystallize into a solid crust. We develop a simple analytic estimate for the onset…

High Energy Astrophysical Phenomena · Physics 2026-05-27 Yudai Suwa , Ken'ichiro Nakazato

Neutron captures produce the vast majority of abundances of elements heavier than iron in the Universe. Beyond the classical slow (s) and rapid (r) processes, there is observational evidence for neutron-capture processes that operate at…

Solar and Stellar Astrophysics · Physics 2025-11-11 Maria Lugaro , Marco Pignatari , René Reifarth , Michael Wischer

In this paper we consider the effects on big bang nucleosynthesis (BBN) of the hadronic decay of a long-lived massive particle. If high-energy hadrons are emitted near the BBN epoch ($t \sim 10^{-2}$ -- $10^2 \sec$), they extraordinarily…

Astrophysics · Physics 2009-11-06 K. Kohri

Elements of nuclear symmetry energy evaluated from different energy density functionals parametrized by fitting selective bulk properties of few representative nuclei are seen to vary widely. Those obtained from experimental data on nuclear…

Nuclear Theory · Physics 2015-08-07 C. Mondal , B. K. Agrawal , J. N. De

With central densities as high as 5-10 times the nuclear saturation density, neutron stars exhibit extreme conditions that cannot be observed elsewhere. They are ideal astrophysical laboratories for probing the composition and properties of…

Solar and Stellar Astrophysics · Physics 2019-09-04 Sophia Han

In past decades a lot of progress has been made towards understanding the main s-process component that takes place in thermally pulsing Asymptotic Giant Branch (AGB) stars. During this process about half of the heavy elements, mainly…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 M. Heil , A. Juseviciute , F. Kaeppeler , R. Gallino , M. Pignatari , E. Uberseder

Production cross sections for neutron-rich nuclei from the fragmentation of a 76Ge beam at 132 MeV/u were measured. The longitudinal momentum distributions of 34 neutron-rich isotopes of elements 13 <= Z <= 27 were scanned using a novel…

We examine Big Bang nucleosynthesis (BBN) in the case of inhomogenous neutrino degeneracy, in the limit where the fluctuations are sufficiently small on large length scales that the present-day element abundances are homogeneous. We…

Astrophysics · Physics 2009-10-31 Scott E. Whitmire , Robert J. Scherrer

The merger of two neutron stars or of a neutron star and a black hole often result in the ejection of a few percents of a solar mass of matter expanding at high speed in space. Being matter coming from the violent disruption of a neutron…

High Energy Astrophysical Phenomena · Physics 2021-12-21 Albino Perego , Friedrich-Karl Thielemann , Gabriele Cescutti

The status of experiments on determination of level density and partial widths of the nuclear reaction products emission in diapason of nucleon binding energy is presented. There are analyzed the sources and magnitude of probable…

Nuclear Experiment · Physics 2011-05-25 A. M. Sukhovoj , V. A. Khitrov

We study the effect of neutrino degeneracy on primordial nucleosynthesis in a universe in which the cosmological scale factor evolves linearly with time. The degeneracy parameter of electron type neutrinos ($\xi_e$) determines the $n/p$…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-02 Parminder Singh , Daksh Lohiya

Within the first 20 minutes of the evolution of the hot, dense, early Universe, astrophysically interesting abundances of deuterium, helium-3, helium-4, and lithium-7 were synthesized by the cosmic nuclear reactor. The primordial abundances…

Astrophysics · Physics 2007-05-23 Gary Steigman

An electron density functional approach for the calculation of the nuclear multipole moments is presented. The electronic matrix elements entering the experimentally observed hyperfine electron-nucleus interaction constants in atoms are…

Nuclear Theory · Physics 2007-05-23 R. L. Pavlov , P. P. Raychev , V. P. Garistov , M. Dimitrova-Ivanovich , J. Maruani

Primordial nucleosynthesis is inevitable during the early evolution of an expanding universe filled with radiation and matter (baryons). However, the precise abundance yields depend sensitively on the baryon density, the radiation content…

Astrophysics · Physics 2007-05-23 Gary Steigman

In this paper we examine the puzzle of neutron formation in atmospheric discharge. While conventional explanation relies on photonuclear reactions, voltages used to recreate such discharges in the lab (1 MV) are thought to be not high…

Nuclear Experiment · Physics 2021-05-21 Max I. Fomitchev-Zamilov

The r-process involves neutron-rich nuclei far off stability for which no experimental cross sections are known. Therefore, one has to rely on theory. The difficulties in the predictions are briefly addressed. To investigate the impact of…

Astrophysics · Physics 2015-06-24 T. Rauscher

We investigate the nucleosynthesis constraint on Lorentz invariance violation in the neutrino sector which influences the formation of light elements by altering the energy density of the Universe and weak reaction rates prior to and during…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-24 Zong-Kuan Guo , Jian-Wei Hu
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