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The chemical evolution of the Universe and several phases of the stellar life are regulated by minute nuclear reactions. The key point for each of these reactions is the value of cross sections at the energies at which they take place in…

核实验 · 物理学 2022-08-22 F. Ferraro , G. F. Ciani , A. Boeltzig , F. Cavanna , S. Zavatarelli

In this article we review the present status of alpha clustering in nuclear systems. First of all, an important aspect is condensation in nuclear matter. Second, the alpha container model, recently been proposed by…

We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the…

天体物理学 · 物理学 2007-05-23 L. -S. The , M. F. El Eid , B. S. Meyer

The Earth is continuously showered by charged cosmic ray particles, naturally produced atomic nuclei moving with velocity close to the speed of light. Among these are ultra high energy cosmic ray particles with energy exceeding 5x10^19 eV,…

高能天体物理现象 · 物理学 2012-06-18 Kunlaya Soiaporn , David Chernoff , Thomas Loredo , David Ruppert , Ira Wasserman

Double-differential cross sections for light-ion (p, d, t, 3He and alpha) production in carbon induced by 96 MeV neutrons have been measured at eight laboratory angles from 20 degrees to 160 degrees in steps of 20 degrees. Experimental…

The fragmentation of quasi-projectiles from the nuclear reaction $^{40}$Ca+$^{12}$C at 25 MeV/nucleon was used to produce excited states candidates to $\alpha$-particle condensation. Complete kinematic characterization of individual decay…

A proposed setting for thermonuclear (Type Ia) supernovae is a white dwarf that has gained mass from a companion to the point of carbon ignition in the core. In the early stages of carbon burning, called the simmering phase, energy released…

太阳与恒星天体物理 · 物理学 2025-01-29 Brendan Boyd , Alan Calder , Dean Townsley , Michael Zingale

We employ analytical and numerical chemical evolution models to study observed trends in abundance ratios involving carbon, nitrogen, and oxygen. Several sets of published stellar yields for both intermediate-mass and massive stars are…

天体物理学 · 物理学 2009-11-06 R. B. C. Henry , M. G. Edmunds , J. Koeppen

It has long been assumed the Earth's solid inner core started to grow when molten iron cooled to its melting point. However, the nucleation mechanism, which is a necessary step of crystallization, has not been well understood. Recent…

地球物理 · 物理学 2022-01-11 Yang Sun , Feng Zhang , Mikhail I. Mendelev , Renata M. Wentzcovitch , Kai-Ming Ho

We study the $\alpha + \alpha + {}^{3}$He cluster structure of ${}^{11}$C within the microscopic cluster model. The calculations essentially reproduce the energy spectra for both negative and positive parity states, particularly the…

核理论 · 物理学 2025-02-12 Ying-Yu Cao , De-Ye Tao , Bo Zhou , Yu-Gang Ma

The three phase transitions - the GUT, the electro-weak and the quark-hadron, which the universe is assumed to have undergone produce very important physical effects if they are assumed to be of first order. It is also important that enough…

天体物理学 · 物理学 2015-06-24 B. Banerjee , R. V. Gavai

Models of primordial and hyper-metal-poor stars with masses similar to the Sun experience an ingestion of protons into the hot core during the core helium flash phase at the end of their red giant branch evolution. This produces a…

太阳与恒星天体物理 · 物理学 2015-05-20 Simon W. Campbell , Maria Lugaro , Amanda I. Karakas

We show that the reaction-diffusion process 3A -> 4A, 3A -> 2A exhibits a different type of continuous phase transition from an active into an absorbing phase. Because of the upper critical dimension d_c = 4/3 we expect the phase transition…

统计力学 · 物理学 2009-11-07 Kwangho Park , Haye Hinrichsen , In-mook Kim

The structure of the Borromean nucleus $^9$Be ($\alpha+\alpha+n$) is addressed within a three-body approach using the analytical transformed harmonic oscillator method. The three-body formalism provides an accurate description of the…

核理论 · 物理学 2016-04-26 J. Casal , M. Rodríguez-Gallardo , J. M. Arias , I. J. Thompson

We employ the constrained density functional theory to investigate cluster phenomena for the $^{12}$C nucleus. The proton and neutron densities are generated from the placement of three $^{4}$He nuclei (alpha particles) geometrically. These…

核理论 · 物理学 2023-06-28 A. S. Umar , K. Godbey , C. Simenel

Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation…

Our Universe is ruled by quantum mechanics and its extension Quantum Field Theory (QFT). However, the explanations for a number of cosmological phenomena such as inflation, dark energy, symmetry breakings, and phase transitions need the…

高能物理 - 唯象学 · 物理学 2015-03-13 Houri Ziaeepour

An introduction to nucleosynthesis, the creation of the elements in the big bang, in interstellar matter and in stars is given. The two--step process $^4$He(2n,$\gamma$)$^6$He and the reverse photodisintegration $^6$He($\gamma$,2n)$^4$He…

核理论 · 物理学 2007-05-23 H. Oberhummer , W. Balogh , V. D. Efros , H. Herndl , R. Hofinger

I present an ab initio calculation of the spectrum of carbon-12, including also the famous Hoyle state. Its structure is discussed and a new interpretation of clustering in nuclear physics is given.

核理论 · 物理学 2015-05-30 Ulf-G. Meißner

A round up of the present status of the conjecture that n alpha nuclei form an alpha-particle condensate in excited states close to the n alpha threshold is given. Experiments which could demonstrate the condensate character are proposed.…

核理论 · 物理学 2009-11-10 P. Schuck , H. Horiuchi , G. Röpke , A. Tohsaki