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Related papers: Reaction rate for two--neutron capture by $^4$He

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It has been suggested that hydrogen ingestion into the helium shell of massive stars could lead to high $^{13}$C and $^{15}$N excesses when the shock of a core-collapse supernova passes through its helium shell. This prediction questions…

Carbon-enhanced metal-poor (CEMP) r/s-stars show surface-abundance distributions characteristic of the so-called intermediate neutron capture process (i-process) of nucleosynthesis. We previously showed that the ingestion of protons in the…

Solar and Stellar Astrophysics · Physics 2021-10-27 S. Goriely , L. Siess , A. Choplin

We present new calculations of the astrophysical $S-$factor and reaction rate for the $^{6}$Li$(p,\gamma )^{7}$Be reaction at energies of 10 keV to 5 MeV in the framework of a modified potential cluster model with forbidden states,…

Recent observations of heavy elements produced by rapid neutron capture (r-process) in the halo have shown a striking and unexpected behavior: within a single star, the relative abundances of r-process elements heavier than Eu are the same…

Astrophysics · Physics 2009-11-06 Brian D. Fields , James W. Truran , John J. Cowan

Some metal-poor stars have abundance patterns which are midway between the slow (s) and rapid (r) neutron capture processes. We show that the helium shell of a fast rotating massive star experiencing a jet-like explosion undergoes two…

Solar and Stellar Astrophysics · Physics 2020-07-22 A. Choplin , N. Tominaga , B. S. Meyer

Nuclear reaction rate ($\lambda$) is a significant factor in the process of nucleosynthesis. A multi-layer directed-weighted nuclear reaction network in which the reaction rate as the weight, and neutron, proton, $^4$He and the remainder…

Nuclear Theory · Physics 2020-10-13 H. L. Liu , D. D. Han , P. Ji , Y. G. Ma

The astrophysical $^7{\rm Be}(p, \gamma)^8{\rm B}$ direct capture process is studied in the framework of a two-body single-channel model with potentials of the Gaussian form. A modified potential is constructed to reproduce the new…

Nuclear Theory · Physics 2021-10-25 E. M. Tursunov , S. A. Turakulov , A. S. Kadyrov , L. D. Blokhintsev

Exclusive and inclusive $(\nu_\mu, \mu^-), (\nu_e, e^-)$ cross-sections and $\mu^-$-capture rates are calculated for ^{12}C and ^{16}O using the consistent random phase approximation (RPA) and pairing model. After a pairing correction is…

Nuclear Theory · Physics 2016-09-08 N. Auerbach , N. Van Giai , O. K. Vorov

We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of $Z\lesssim 10^{-3}\,Z_\odot$. We find that for progenitors of $\sim 11$--$15\,{\rm M}_\odot$, the neutrons…

Solar and Stellar Astrophysics · Physics 2016-03-16 Projjwal Banerjee , Yong-Zhong Qian , Alexander Heger , Wick Haxton

A new mechanism of nuclear excitation via two-photon electron transitions (NETP) is proposed and studied theoretically. As a generic example, detailed calculations are performed for the $E1E1$ $1s2s\,^1S_0 \rightarrow 1s^2\,^1S_0$…

Atomic Physics · Physics 2016-12-09 A. V. Volotka , A. Surzhykov , S. Trotsenko , G. Plunien , Th. Stöhlker , S. Fritzsche

$^{192}$Pt is produced solely by the slow neutron capture (\textit{s}) nucleosynthesis process and hence an accurate ($n$,$\gamma $) reaction rate for this nuclide would allow its use as an important calibration point near the termination…

Nuclear Experiment · Physics 2015-06-17 P. E. Koehler , K. H. Guber

Correlations of back-to-back coincident $\Lambda d$ and $\Lambda t$ pairs from the stopped $K^-$ reaction on $^4$He had been investigated, thereby $\Lambda d$ and $\Lambda t$ branches of non-mesonic three- and four-nucleon absorption…

During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of…

Astrophysics · Physics 2007-05-23 John J. Cowan , Christopher Sneden

The present status of the nuclear reaction rates determining the solar neutrino flux is discussed. This includes the reaction rates for the two branching ratios of the three pp-chains involving the reactions 3He(3He,2p)4He and…

Nuclear Theory · Physics 2008-11-26 H. Oberhummer , A. N. Ivanov , N. I. Troitskaya , M. Faber

Background: The breakout from the hot Carbon-Nitrogen-Oxigen (CNO) cycles can trigger the rp-process in type I x-ray bursts. In this environment, a competition between $^{15}\text{O}(\alpha,\gamma){^{19}\text{Ne}}$ and the two-proton…

Nuclear Theory · Physics 2016-12-01 J. Casal , E. Garrido , R. de Diego , J. M. Arias , M. Rodríguez-Gallardo

The rates of electron neutrino capture on neutron, electron anti-neutrino capture on proton, and their reverse processes are important for understanding the production of heavy elements in the supernova environment above the protoneutron…

Astrophysics · Physics 2009-11-11 Huaiyu Duan , Yong-Zhong Qian

While the high-entropy wind (HEW) of Type II supernovae remains one of the more promising sites for the rapid neutron-capture (r-) process, hydrodynamic simulations have yet to reproduce the astrophysical conditions under which the latter…

Solar and Stellar Astrophysics · Physics 2009-11-13 K. Farouqi , K. -L. Kratz , L. I. Mashonkina , B. Pfeiffer , J. J Cowan , F. -K. Thielemann , J. W. Truran

Standard Big Bang Nucleosynthesis (BBN) predicts the abundances of the light elements in the early universe. Even if the overall agreement with the experimental data is good, still some discrepancies exist on the relic abundances of…

Nuclear Theory · Physics 2020-12-16 Alex Gnech

New measurements and reaction model calculations are reported for single neutron pickup reactions onto a fast \nuc{22}{Mg} secondary beam at 84 MeV per nucleon. Measurements were made on both carbon and beryllium targets, having very…

The structure of neutron-rich $\Lambda$ hypernucleus, $^7_{\Lambda}$He is studied within the framework of an $\alpha +\Lambda +n+n$ four-body cluster model. We predict second $3/2^+$ and $5/2^+$ states, corresponding to a $0s$ $\Lambda$…

Nuclear Theory · Physics 2015-06-11 E. Hiyama , M. Isaka , M. Kamimura , T. Myo , T. Motoba