Resonance parameters of the first 1/2+ state in 9Be and astrophysical implications

• Spectra of the Be-9(e, e') reaction have been measured at the Superconducting Darmstadt Electron Linear Accelerator at an electron energy of E-0 = 73 MeV and scattering angles of 93 degrees and 141 degrees with high-energy resolution up to excitation energies of E-x = 8 MeV. The astrophysically relevant resonance parameters of the first excited 1/2(+) state of Be-9 have been extracted in a one-level approximation of R-matrix theory, resulting in resonance energy E-R = 1.748(6) MeV and width Gamma(R) = 274(8) keV, which are in good agreement with the latest Be-9(gamma, n) experiment but with considerably improved uncertainties. However, the reduced B(E1) transition strength deduced from an extrapolation of the (e, e') data to the photon point is smaller by a factor of two. Implications of the new results for possible production of C-12 in neutron-rich astrophysical scenarios are discussed.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

momentum-transfers

isospin-forbidden electroexcitation

spectrometer

r-process

inelastic electron-scattering

excitation

dalinac

shell-model

supernova bubble

low

light-nuclei

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