E1 strength of the subthreshold 3/2+ state in 15O studied by Coulomb excitation

Yamada, Kazunari; Motobayashi, T.; Akiyoshi, H.; Aoi, N.; Fülöp, Zs.; Gomi, T.; Higurashi, Y.; Imai, N.; Iwasa, N.; Iwasaki, H.; Iwata, Y.; Kobayashi, Hiroshi; Kurokawa, M.; Liu, Z.; Minemura, T.; Ozawa, Shogo; Sakuraï, H.; Serata, M.; Shimoura, S.; Takeuchi, Satoshi; Teranishi, Takashi; Yanagisawa, Y.; Yoshida, Kôichi; Ishihara, M.

doi:10.1016/j.physletb.2003.11.024

Cited by 43 publications

(41 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is worth noting that a reliable extrapolation of the LUNA data to the solar Gamow peak requires combining low-energy with high-energy data, namely the results of the LENA experiment at TUNL (Runkle et al 2005). Additional information is provided by experiments that used indirect methods, such as the Doppler shift attenuation method (Bertone et al 2001;Schürmann et al 2008), Coulomb excitation (Yamada et al 2004), and asymptotic normalization coefficients (ANC; Mukhamedzhanov et al 2003). It is worth noting that the uncertainty on data at high energy affects the low energy extrapolation.…”

Section: Reaction Rate Uncertaintiesmentioning

confidence: 99%

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Cristallo

Leva

Imbriani

et al. 2014

A&A

View full text Add to dashboard Cite

Context. The origin of fluorine is a longstanding problem in nuclear astrophysics. It is widely recognized that asymptotic giant branch (AGB) stars are among the most important contributors to the Galactic fluorine production. Aims. In general, extant nucleosynthesis models overestimate the fluorine production by AGB stars with respect to observations. Although those differences are rather small at solar metallicity, low metallicity AGB stellar models predict fluorine surface abundances up to one order of magnitude larger than the observed ones. Methods. As part of a project devoted to reducing the uncertainties in the nuclear physics that affect the nucleosynthesis in AGB stellar models, we review the relevant nuclear reaction rates involved in the fluorine production or destruction. We perform this analysis on a model with initial mass M = 2 M and Z = 0.001. Results. We found that the major uncertainties are due to the 13 C(α,n) 16 O, the 19 F(α,p) 22 Ne, and the 14 N(p,γ) 15 O reactions. A change in the corresponding reaction rates within the present experimental uncertainties implies surface 19 F variations at the AGB tip lower than 10%, thus much smaller than observational uncertainties. For some α capture reactions, however, cross sections at astrophysically relevant energies are determined on the basis of nuclear models, in which some low-energy resonance parameters are very poorly known. Thus, larger variations in the rates of those processes cannot be excluded. That being so, we explore the effects of the variation in some α capture rates well beyond the current published uncertainties. The largest 19 F variations are obtained by varying the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions. Conclusions. The currently estimated uncertainties of the nuclear reaction rates involved in the production and destruction of fluorine produce minor 19 F variations in the ejecta of AGB stars. Analysis of some α capture processes that assume a wider uncertainty range determines 19 F abundances in better agreement with recent spectroscopic fluorine measurements at low metallicity. In the framework of this scenario, the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions show the strongest effects on fluorine nucleosynthesis. The presence of poorly known low-energy resonances make such a scenario possible, even if it is unlikely. We plan to measure these resonances directly.

show abstract

Section: Reaction Rate Uncertaintiesmentioning

confidence: 99%

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Cristallo

Leva

Imbriani

et al. 2014

A&A

View full text Add to dashboard Cite

show abstract

“…Then for the total radiative width we get two values: 0.026 eV and 3.75 eV. The first value is too low compared to the measurements in [25][26][27]. The higher value does not contradict to [27] but significantly exceeds the results obtained in [25,26].…”

Section: Examplesmentioning

confidence: 55%

“…The first value is too low compared to the measurements in [25][26][27]. The higher value does not contradict to [27] but significantly exceeds the results obtained in [25,26]. Because the higher value of the total radiative width corresponds to the constructive interference of the internal and channel radiative width amplitudes, the channel radiative width 0.79±0.24 eV provides the low limit of the radiative width.…”

Section: Examplesmentioning

confidence: 58%

See 1 more Smart Citation

Asymptotic normalization coefficients and radiative widths

Mukhamedzhanov

Pang

2015

Phys. Rev. C

View full text Add to dashboard Cite

Asymptotic normalization coefficent (ANC) is important quantity in calculation of the radiative width amplitudes providing limits on the radiative width. Here we present some examples showing connection between the ANC and radiative width. In particular, the radiative width of the E1Phys. A 217, 29 (1973) ] is (1.2 ± 0.2) × 10 −2 eV. Meantime the ANC for the first excited state in 17 F puts a low limit on the radiative width, which is (3.4 ± 0.50) × 10 −2 eV. Such a strong disagreement between the measured radiative width and the low limit imposed by the ANC calls for a new measurement of this radiative widh. Other examples are also considered.

show abstract

“…After the year 2000, the R-matrix results of Schröder et al [20] have been revised by several works, on theoretical [24], indirect [25,26,27,28] and direct experimental [22,29] grounds. The most dramatic revision was for capture to the ground state in 15 O; the following section focuses on this particular transition.…”

Section: Which Nuclear Energy Range Is Of Astrophysical Interest?mentioning

confidence: 99%

CNO hydrogen burning studied deep underground

et al. 2006

Self Cite

View full text Add to dashboard Cite

Abstract. In stars, four hydrogen nuclei are converted into a helium nucleus in two competing nuclear fusion processes, namely the proton-proton chain (p-p chain) and the carbon-nitrogen-oxygen (CNO) cycle. For temperatures above 20 million kelvin, the CNO cycle dominates energy production, and its rate is determined by the slowest process, the 14 N(p, γ) 15 O radiative capture reaction. This reaction proceeds through direct and resonant capture into the ground state and several excited states in 15 O. High energy data for capture into each of these states can be extrapolated to stellar energies using an R-matrix fit. The results from several recent extrapolation studies are discussed. A new experiment at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in Italy's Gran Sasso laboratory measures the total cross section of the 14 N(p, γ) 15 O reaction with a windowless gas target and a 4π BGO summing detector, down to center of mass energies as low as 70 keV. After reviewing the characteristics of the LUNA facility, the main features of this experiment are discussed, as well as astrophysical scenarios where cross section data in the energy range covered have a direct impact, without any extrapolation. PACS

show abstract

E1 strength of the subthreshold 3/2+ state in 15O studied by Coulomb excitation

Cited by 43 publications

References 22 publications

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Asymptotic normalization coefficients and radiative widths

CNO hydrogen burning studied deep underground

Contact Info

Product

Resources

About

E1 strength of the subthreshold 3/2+ state in 15O studied by Coulomb excitation

Cited by 43 publications

References 22 publications

Effects of nuclear cross sections on19F nucleosynthesis at low metallicities

Effects of nuclear cross sections on19F nucleosynthesis at low metallicities

Asymptotic normalization coefficients and radiative widths

CNO hydrogen burning studied deep underground

Contact Info

Product

Resources

About

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities