Proton-Proton Weak Capture in Chiral Effective Field Theory
- Pisa U., INFN-Pisa
- Old Dominion U., JLAB
- INFN-Pisa
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 (LEC's) 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 $$\beta$$ 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 $$S(0)=(4.030 \pm 0.006)\times 10^{-23}$$ MeV fm$^2$, with a $$P$$-wave contribution of $$0.020\times 10^{-23}$$ MeV fm$^2$. The theoretical uncertainty is due to the fitting procedure of the LEC's and to the cutoff dependence. It is shown that polynomial fits to parametrize the energy dependence of the $$S$$-factor are inherently unstable.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1079208
- Report Number(s):
- JLAB-THY-13-1699; DOE/OR/23177-2495; arXiv:1303.3124
- Journal Information:
- Phys. Rev. Lett., Vol. 110, Issue 19
- Country of Publication:
- United States
- Language:
- English
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