Infrared regularization for spin-1 fields

We extend the method of infrared regularization to spin-1 fields. As applications, we discuss the chiral extrapolation of the rho meson mass from lattice QCD data and the pion-rho sigma term.Comment: 22 pp, 5 fig

A formalism for the study of K+π ΣK^{+}\pi\,\Sigma photoproduction in the Λ∗(1405)\Lambda^{\ast}(1405) region

We present a formalism for the low-energy analysis of the $\gamma p\rightarrow K^{+}\pi\Sigma$ photoproduction reaction in the $\Lambda^{\ast}(1405)$ resonance region. In particular, the constraints arising from unitarity, gauge invariance and chiral perturbation theory are discussed in some detail