The astrophysical S factor for proton-proton weak capture is calculated in chiral effective field theory over the center-of-mass relative-energy range 0–100 keV. The chiral two-nucleon potential derived up to next-to-next-to-next-to leading order is augmented by the full electromagnetic interaction including, beyond Coulomb, two-photon and vacuum-polarization corrections. The low-energy constants entering the weak current operators are fixed so as to reproduce the A=3 binding energies and magnetic moments and the Gamow-Teller matrix element in tritium β decay. Contributions from S and P partial waves in the incoming two-proton channel are retained. The S factor at zero energy is found to be S(0)=(4.030±0.006)×10⁻²³ MeV fm², with a P-wave contribution of 0.020×10⁻²³ MeV fm². The theoretical uncertainty is due to the fitting procedure of the low-energy constants and to the cutoff dependence.
Proton-Proton Weak Capture in Chiral Effective Field Theory
MARCUCCI, LAURA ELISA;
2013-01-01
Abstract
The astrophysical S factor for proton-proton weak capture is calculated in chiral effective field theory over the center-of-mass relative-energy range 0–100 keV. The chiral two-nucleon potential derived up to next-to-next-to-next-to leading order is augmented by the full electromagnetic interaction including, beyond Coulomb, two-photon and vacuum-polarization corrections. The low-energy constants entering the weak current operators are fixed so as to reproduce the A=3 binding energies and magnetic moments and the Gamow-Teller matrix element in tritium β decay. Contributions from S and P partial waves in the incoming two-proton channel are retained. The S factor at zero energy is found to be S(0)=(4.030±0.006)×10⁻²³ MeV fm², with a P-wave contribution of 0.020×10⁻²³ MeV fm². The theoretical uncertainty is due to the fitting procedure of the low-energy constants and to the cutoff dependence.File | Dimensione | Formato | |
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PhysRevLett.110.192503.pdf
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