arXiv subjects

N. Wies

Publications and source records attributed to N. Wies.

3 recordsLinked to original sources

arXiv2006

Magnetic dipole moment of the $Δ(1232)$ in chiral perturbation theory

The magnetic dipole moment of the $Δ(1232)$ is calculated in the framework of manifestly Lorentz-invariant baryon chiral perturbation theory in combination with the extended on-mass-shell renormalization scheme. As in the case of the nucleon, at leading order both isoscalar and isovector anomalous magnetic moments are given in terms of two low-energy constants. In contrast to the nucleon case, at next-to-leading order the isoscalar anomalous magnetic moment receives a (real) loop contribution. Moreover, due to the unstable nature of the $Δ(1232)$, at next-to-leading order the isovector anomalous magnetic moment not only receives a real but also an imaginary loop contribution.

hep-ph↗

arXiv2006

Consistency of the $πΔ$ interaction in chiral perturbation theory

We analyze the constraint structure of a spin-3/2 particle interacting with a pseudoscalar. Requiring the self consistency of the considered effective field theory imposes restrictions on the possible interaction terms. In the present case we derive two constraints among the three lowest-order $πΔ$ interaction terms. From these constraints we find that the total Lagrangian is invariant under the so-called point transformation. On the other hand, demanding the invariance under the point transformation alone is less stringent and produces only classes of relations among the coupling constants.

hep-ph↗

arXiv2005

Including the $Δ(1232)$ resonance in baryon chiral perturbation theory

Baryon chiral perturbation theory with explicit $Δ(1232)$ degrees of freedom is considered. Using the extended on-mass-shell renormalization scheme, a manifestly Lorentz-invariant effective field theory with a systematic power counting is obtained. As applications we discuss the mass of the nucleon, the pion-nucleon sigma term, and the pole of the $Δ$ propagator.

hep-ph↗