Off-shell effects in the energy dependence of the 7Be(p, γ)8B astrophysical S factor

Low-lying continuum structures in8Band8Liin a microscopic model

“…For example, in Ref. [7] we noted that our microscopic 4 He + 3 He + p cluster model also seemed to indicate the presence of a 1 + resonance at around 1.5 MeV.…”

“…The solid curve shows the M1 cross section coming from the 1 + initial states in the present model. The dot-dashed curve is an E1 cross section whose energy dependence is taken from [6,7] and its absolute normalization is fitted (by eye) to the low-energy Filippone data. The dotted curve is the sum of the two.…”

“…As we mentioned, the precise reproduction of the known 1 + state in 8 B (and in 8 Li) is a first priority. In most of our previous calculations for 8 B [6,7] we used the Minnesota (MN) force. However, it turned out that this interaction gave an incorrect channel spin ratio for the 1 + 1 state of 8 Be [17], which is a member of a T = 1 triplet together with the 1 + states of 8 B and 8 Li.…”

Few-Body Resonances in Light Nuclei

“…Although astrophysically only the very low-energy (practically E = 0) cross sections are important, these values can be substantially influenced by the higher-energy continuum structures present in 8 Li and 8 B. For example, the extrapolation of the astrophysical S factor S(E) of the 7 Be(p, γ) 8 B reaction could be affected by the existence of a second 1 + state at low energies [37]. With this motivation, we searched for low-energy 1 + states in 8 Li and 8 B [10].…”

Effects of 8B size on the low-energy 7Be(p,γ)8B cross section

“…Refs. [13,11,14]). Its absolute value, however, depends onc and has thus to be determined experimentally.…”