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We show that chiral symmetry and gauge invariance enforce relations between the short-distance physics that occurs in a number of electroweak and pionic reactions on light nuclei. Within chiral perturbation theory this is manifested via the appearance of the same axial isovector two-body contact term in pi- d -> n n gamma, p-wave pion production in NN collisions, tritium beta decay, pp fusion, nu d scattering, and the hep reaction. Using a Gamow-Teller matrix element obtained from calculations of pp fusion as input we compute the neutron spectrum obtained in pi- d -> n n gamma. With the short-distance physics in this process controlled from p p -> d e+ nu_e the theoretical uncertainty in the nn scattering length extracted from pi- d -> n n gamma is reduced by a factor larger than three, to <~0.05 fm.
We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation w
Background: Modern ab initio theory combined with high-quality nucleon-nucleon (NN) and three-nucleon (3N) interactions from chiral effective field theory (EFT) can provide a predictive description of low-energy light-nuclei reactions relevant for as
The existence of superfluidity of the neutron component in the core of a neutron star, associated specifically with triplet $P-$wave pairing, is currently an open question that is central to interpretation of the observed cooling curves and other neu
We have performed the first high precision measurement of the coherent neutron scattering length of deuterium in a pure sample using neutron interferometry. We find b_nd = (6.665 +/- 0.004) fm in agreement with the world average of previous measureme
We study excited-state properties of neutron-rich calcium isotopes based on chiral two- and three-nucleon interactions. We first discuss the details of our many-body framework, investigate convergence properties, and for two-nucleon interactions benc