7 research outputs found

    High energy solar neutrinos and p-wave contributions to ^3He(p,\nue^+)^4He

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    High energy solar neutrinos can come from the hep reaction ^3He(p,\nue^+)^4He with a large end point energy of 18.8 MeV. Understanding the hep reaction may be important for interpreting solar neutrino spectra. We calculate the contribution of the axial charge transition 3P0→1S0^3P_0\to ^1S_0 to the hep thermonuclear S factor using a one-body reaction model involving a nucleon moving in optical potentials. Our result is comparable to or larger than previous calculations of the s-wave Gamow Teller contribution. This indicates that the hep reaction may have p-wave strength leading to an enhancement of the S factor.Comment: 4 pages, 1 ps figure, very minor changes, Phys. Rev. C in pres

    Realistic Calculation of the hep Astrophysical Factor

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    The astrophysical factor for the proton weak capture on 3He is calculated with correlated-hyperspherical-harmonics bound and continuum wave functions corresponding to a realistic Hamiltonian consisting of the Argonne v18 two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vector and axial-vector components, that include one- and many-body terms. All possible multipole transitions connecting any of the p-3He S- and P-wave channels to the 4He bound state are considered. The S-factor at a p-3He center-of-mass energy of 10 keV, close to the Gamow-peak energy, is predicted to be 10.1 10^{-20} keV b, a factor of five larger than the standard-solar-model value. The P-wave transitions are found to be important, contributing about 40 % of the calculated S-factor.Comment: 8 pages RevTex file, submitted to Phys. Rev. Let

    Modern theories of low-energy astrophysical reactions

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    We summarize recent ab initio studies of low-energy electroweak reactions of astrophysical interest, relevant for both big bang nucleosynthesis and solar neutrino production. The calculational methods include direct integration for np radiative and pp weak capture, correlated hyperspherical harmonics for reactions of A=3,4 nuclei, and variational Monte Carlo for A=6,7 nuclei. Realistic nucleon-nucleon and three-nucleon interactions and consistent current operators are used as input.Comment: 29 pages, 4 figure

    Exchange currents in low-energy nucleon capture by 3He

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    Electrical Engineering, Mathematics and Computer Scienc
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