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The theory governing the strong nuclear force—quantum chromodynamics—predicts that at sufficiently high energy densities, hadronic nuclear matter undergoes a deconfinement transition to a new phase of quarks and gluons 1 . Although this has been observed in ultrarelativistic heavy-ion collisions 2 , 3 , it is currently an open question whether quark matter exists inside neutron stars 4 . By combining astrophysical observations and theoretical ab initio calculations in a model-independent way, we find that the inferred properties of matter in the cores of neutron stars with mass corresponding to 1.4 solar masses ( M ⊙ ) are compatible with nuclear model calculations. However, the matter in the interior of maximally massive stable neutron stars exhibits characteristics of the deconfined phase, which we interpret as evidence for the presence of quark-matter cores. For the heaviest reliably observed neutron stars 5 , 6 with mass M  ≈ 2 M ⊙ , the presence of quark matter is found to be linked to the behaviour of the speed of sound c s in strongly interacting matter. If the conformal bound c s 2 ≤ 1 / 3 (ref. 7 ) is not strongly violated, massive neutron stars are predicted to have sizable quark-matter cores. This finding has important implications for the phenomenology of neutron stars and affects the dynamics of neutron star mergers with at least one sufficiently massive participant. The cores of neutron stars could be made of hadronic matter or quark matter. By combining first-principles calculations with observational data, evidence for the presence of quark matter in neutron star cores is found.

The book covers all aspects of laboratory elementary particle phenomenology, dealing with the two main interactions as described by the electroweak theory and quantum chromodynamics.It outlines the historical development of the theoretical framework, including the experimental motivations and discoveries of the last and present centuries.

27Al, 51V, 52Cr, 55Mn, 56Fe and 58Ni nuclei are some structural fusion substances. The neutron incident energy around 14–15 MeV is adequate to excite the nucleus for the reactions such as (n, p), (n, d), (n, 2n), (n, t), and (n, α). For fusion reactor technology, the reaction cross-sectional data have a critical importance in fusion reactors and development. Neutron irradiation produces considerable modifications in the mechanical and physical properties of each of the structural fusion material systems raising feasibility questions and design limitations. In this paper, for some structural fusion materials (n, α) reactions such as 52Cr(n, α)49Ti, 51V(n, α)48Si, 27Al(n, α)24Na, 58Ni(n, α)55Fe, 56Fe(n, α)53Cr and 55Mn(n, α)52V were done up to 40 MeV incident neutron energy. In the calculations, the equilibrium and pre-equilibrium impacts have been used. Calculations have been carried out with TALYS 1.9 and EMPIRE 3.2 (Malta) nuclear model codes. Results from performed calculations have been compared with the experimental nuclear reaction data, ENDF/B-VII.b4, JENDL-4.0 and JEFF-3.2 evaluated data.

For the unreacted nuclear model, predecessors have established a more complete theoretical model under the assumption of steady-state conditions. And deduced the general equation of the rate of reduction of pellets. In this paper, we focus on the model of iron ore pellet reduction, not only establishing a single-interface unreacted nuclear model but also establishing a three-interface unreacted nuclear model. The activation energy and diffusion coefficient of iron ore reaction under certain conditions are obtained. According to the fitted images, the speed limit factors in the iron ore pellet reaction model are analyzed completely. In this paper, a pellet decomposition model was established to try to determine the kinetic and thermodynamic parameters of the pellet reaction without the need for experimentation, to simulate the reduction of pellets, and to determine the process of limiting the reaction rate and the process Strengthen.

The two most important developments in nuclear physics were the shell model and the collective model. The former gives the formal framework for a description of nuclei in terms of interacting neutrons and protons. The latter provides a very physical but phenomenological framework for interpreting the observed properties of nuclei. A third approach, based on variational and mean-field methods, brings these two perspectives together in terms of the so-called unified models. Together, these three approaches provide the foundations on which nuclear physics is based. They need to be understood by everyone practicing or teaching nuclear physics, and all those who wish to gain an understanding of the foundations of the models and their relationships to microscopic theory as given by recent developments in terms of dynamical symmetries.

Geo- und astrophysikalisch motivierte Strömungen, wie sie in der Atmosphäre, in den Ozeanen oder im Inneren von Planeten auftreten, lassen sich in rotierenden Experimenten mit homogenen Fluiden untersuchen. In dieser Arbeit werden Untersuchungen zu Trägheitswellen und Wellenattraktoren in einer Kugelschale und einem rechteckigen Tank gezeigt. Viele geophysikalische Anwendungen mit planetaren Skalen motivieren den Einsatz von sphärischen Geometrien. Mit dem Kugelspaltexperiment, bestehend aus zwei rotierenden konzentrisch angeordneten Kugelschalen, werden die Anregung und Ausbildung verschiedener Wellenphänomene sowie der internen Grenzschichten untersucht. Durch eine Modulation der Rotationsgeschwindigkeit an der Innenkugel in Form einer Sinuskurve werden Wellen erzeugt, die an den gekrümmten Rändern des Modells mehrfach reflektiert werden und somit bestimmten Bahnen folgen. Für den Vergleich mit numerischen Untersuchungen werden unterschiedliche Visualisierungen und Messtechniken spezifiziert. Die numerische Simulation erlaubt dabei die Untersuchung in Parameterbereichen mit Instabilitäten, die für die experimentelle Untersuchung schwer zugänglich sind.

In this review we will present the results of recent β -decay studies using the total absorption technique that cover topics of interest for applications, nuclear structure and astrophysics. The decays studied were selected primarily because they have a large impact on the prediction of (a) the decay heat in reactors, important for the safety of present and future reactors and (b) the reactor electron anti-neutrino spectrum, of interest for particle/nuclear physics and reactor monitoring. For these studies the total absorption technique was chosen, since it is the only method that allows one to obtain β -decay probabilities free from a systematic error called the Pandemonium effect. The total absorption technique is based on the detection of the γ cascades that follow the initial β decay. For this reason the technique requires the use of calorimeters with very high γ detection efficiency. The measurements presented and discussed here were performed mainly at the IGISOL facility of the University of Jyväskylä (Finland) using isotopically pure beams provided by the JYFLTRAP Penning trap. Examples are presented to show that the results of our measurements on selected nuclei have had a large impact on predictions of both the decay heat and the anti-neutrino spectrum from reactors. Some of the cases involve β -delayed neutron emission thus one can study the competition between γ - and neutron-emission from states above the neutron separation energy. The γ -to-neutron emission ratios can be used to constrain neutron capture (n, γ ) cross sections for unstable nuclei of interest in astrophysics. The information obtained from the measurements can also be used to test nuclear model predictions of half-lives and Pn values for decays of interest in astrophysical network calculations. These comparisons also provide insights into aspects of nuclear structure in particular regions of the nuclear chart.

The quantum-mechanical nuclear-shell structure determines the stability and limits of the existence of the heaviest nuclides with large proton numbers Z  ≳ 100 (refs. 1 – 3 ). Shell effects also affect the sizes and shapes of atomic nuclei, as shown by laser spectroscopy studies in lighter nuclides 4 . However, experimental information on the charge radii and the nuclear moments of the heavy actinide elements, which link the heaviest naturally abundant nuclides with artificially produced superheavy elements, is sparse 5 . Here we present laser spectroscopy measurements along the fermium ( Z  = 100) isotopic chain and an extension of data in the nobelium isotopic chain ( Z  = 102) across a key region. Multiple production schemes and different advanced techniques were applied to determine the isotope shifts in atomic transitions, from which changes in the nuclear mean-square charge radii were extracted. A range of nuclear models based on energy density functionals reproduce well the observed smooth evolution of the nuclear size. Both the remarkable consistency of model prediction and the similarity of predictions for different isotopes suggest a transition to a regime in which shell effects have a diminished effect on the size compared with lighter nuclei. Laser spectroscopy measurements of the fermium isotopic chain show a smooth trend in the nuclear size of heavy actinide elements, and diminishing shell effects on the size evolution compared with lighter nuclei.

Understanding the nuclear properties in the vicinity of 100 Sn, which has been suggested to be the heaviest doubly magic nucleus with proton number Z equal to neutron number N , has been a long-standing challenge for experimental and theoretical nuclear physics. In particular, contradictory experimental evidence exists regarding the role of nuclear collectivity in this region of the nuclear chart. Here, we provide further evidence for the doubly magic character of 100 Sn by measuring the ground-state electromagnetic moments and nuclear charge radii of indium ( Z  = 49) isotopes as N approaches 50 from above using precision laser spectroscopy. Our results span almost the complete range between the two major closed neutron shells at N  = 50 and N  = 82 and reveal parabolic trends as a function of the neutron number, with a clear reduction towards these two closed neutron shells. A detailed comparison between our experimental results and numerical results from two complementary nuclear many-body frameworks (density functional theory and ab initio methods) exposes deficiencies in nuclear models and establishes a benchmark for future theoretical developments. Precision laser spectroscopy of ground-state electromagnetic moments and nuclear charge radii of indium shows that 100 Sn has closed proton and neutron shells. The results serve as a benchmark for future theoretical models.

High-resolution laser spectroscopy can be used to precisely measure atomic hyperfine structures and shifts in spectral lines. These nuclear perturbations of the atomic structure provide insight into the bulk properties of nuclei as well as the intricate details of the nucleon–nucleon interactions inside the atomic nucleus. Collinear laser spectroscopy in particular allows for the extraction of nuclear moments and changes in the mean-square charge radii with high precision. We provide an overview of the manner in which collinear laser spectroscopy is currently implemented at radioactive ion beam facilities. Through examples, we illustrate how this method gives access to direct and nuclear model-independent evidence for changes in nuclear spins, electromagnetic moments and nuclear radii caused by structural changes in atomic nuclei.