A two-nucleon potential and consistent electromagnetic currents are derived in chiral effective field theory (chi EFT) at, respectively, Q^2 (or N2LO) and eQ (or N3LO), where Q generically denotes the low-momentum scale and e is the electric charge. Dimensional regularization is used to renormalize the pion-loop corrections. A simple expression is derived for the magnetic dipole (M1) operator associated with pion loops, consisting of two terms, one of which is determined, uniquely, by the isospin-dependent part of the two-pion-exchange potential. This decomposition is also carried out for the M1 operator arising from contact currents, in which the unique term is determined by the contact potential. Finally, the low-energy constants entering the N2LO potential are fixed by fits to the np S-and P-wave phase shifts up to 100 MeV laboratory energies.
Electromagnetic currents and magnetic moments in chiral effective field theory (chi EFT)
GIRLANDA, Luca;
2009-01-01
Abstract
A two-nucleon potential and consistent electromagnetic currents are derived in chiral effective field theory (chi EFT) at, respectively, Q^2 (or N2LO) and eQ (or N3LO), where Q generically denotes the low-momentum scale and e is the electric charge. Dimensional regularization is used to renormalize the pion-loop corrections. A simple expression is derived for the magnetic dipole (M1) operator associated with pion loops, consisting of two terms, one of which is determined, uniquely, by the isospin-dependent part of the two-pion-exchange potential. This decomposition is also carried out for the M1 operator arising from contact currents, in which the unique term is determined by the contact potential. Finally, the low-energy constants entering the N2LO potential are fixed by fits to the np S-and P-wave phase shifts up to 100 MeV laboratory energies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
