The electric dipole moment of the neutron in chiral perturbation theory 1
نویسنده
چکیده
We calculate the electric dipole moments of the neutron and the Λ within the framework of heavy baryon chiral perturbation theory. They are induced by strong CP-violating terms of the effective Lagrangian in the presence of the vacuum angle θ 0. The construction of such a Lagrangian is outlined and we are able to give an estimate for θ 0 .
منابع مشابه
Theta Vacua, QCD Sum Rules, and the Neutron Electric Dipole Moment
We present a detailed study of the electric dipole moment of the neutron induced by a vacuum theta angle within the framework of QCD sum rules. At next-to-next-to leading order in the operator product expansion, we find the result dn(θ) = 1.2 × 10 −16θ̄e · cm, to approximately 40% precision. With the current experimental bound this translates into a limit on the theta parameter of |θ̄| < 6 × 10−1...
متن کاملNucleon Electric Dipole Moments from QCD Sum Rules
The electric dipole moments of nucleons ( NEDM, dN ) are calculated using the method of QCD sum rules. Our calculations are based on the parity ( 6P ) and time reversal ( 6T ) violating parameter θ̄ in QCD and establish a functional dependence of the NEDM on θ̄, without assuming a perturbative expansion of this symmetry breaking parameter. The results obtained from the QCD sum rules approach are ...
متن کاملChiral Estimates of Strong CP Violation Revisited
The effects of the CP violating θ term in the QCD Lagrangian upon low energy hadronic phenomenology are reconsidered. Strong CP violating interactions among Goldstone bosons and octet baryons are incorporated into an effective chiral Lagrangian framework. The θ term’s impact upon the decays η → ππ and π → γγ is then investigated but found to be extremely small. A refined model independent estim...
متن کاملNeutron Electric Dipole Moment on the Lattice: a Theoretical Reappraisal
We present a strategy for a lattice evaluation of the neutron electric dipole moment induced by the strong CP violating term of the QCD Lagrangian. Our strategy is based on the standard definition of the electric dipole moment, involving the charge density operator J0, in case of three flavors with non-degenerate masses. We present a complete diagrammatic analysis showing how the axial chiral W...
متن کاملQCD corrections to the electric dipole moment of the neutron in the MSSM
We consider the QCD corrections to the electric dipole moment of the neutron in the Minimal Supersymmetric Standard Model. We provide a master formula for the Wilson coefficients at the low energy scale including for the first time the mixing between the electric and chromoelectric operators and correcting widely used previous LO estimates. We show that, because of the mixing between the electr...
متن کامل