Chiral Effective Theories

These are the proceedings of the workshop on ``Chiral Effective Theories'' held at the Physikzentrum Bad Honnef of the Deutsche Physikalische Gesellschaft, Bad Honnef, Germany from November 30 to December 4, 1998. The workshop concentrated on Chiral Perturbation Theory in its various settings and its relations with lattice QCD and dispersion theory. Included are a short contribution per talk and a listing of some review papers on the subject.Comment: Miniproceedings of the meeting on Chiral Effective Theories, Bad Honnef, Germany, Nov. 30-Dec. 4, 1998, LaTeX2e, 51 page

Isospin dependence of the three-nucleon force

We classify $A$--nucleon forces according to their isospin dependence and discuss the most general isospin structure of the three--nucleon force. We derive the leading and subleading isospin--breaking corrections to the three--nucleon force using the framework of chiral effective field theory.Comment: 21 pages, 6 figure

Dynamically Generated Resonances in the Chiral Unitary Approach to Meson Baryon Interaction

In this talk we report on the use of a chiral unitary approach for the interaction of the octets of meson and baryon and the octet of mesons with the decuplet of baryons. Two octets of $J^{\pi}=1/2^-$ baryon states and a singlet are generated dynamically in the first case, resulting in the case of strangeness $S=-1$ in two poles of the scattering matrix close to the nominal $\Lambda(1405)$ resonance. In the second case many resonances are also generated, among them an exotic baryon with S=1 corresponding to a $\Delta K$ resonance. We make suggestions of experiments which could show evidence for the existence of these states.Comment: Talk at the MENU04 Symposium, Beijing, September 200

QCD Accurately Predicts the Induced Pseudoscalar Coupling Constant

Using chiral Ward identities of QCD, we derive a relation for the induced pseudoscalar coupling constant which is accurate within a few percent, $g_P = 8.44 \pm 0.16$.Comment: 5pp, LaTeX, CRN-94/1

Towards a precise determination of the scattering amplitudes of the charmed and light-flavor pseudoscalar mesons

We study the scattering of the light-flavor pseudoscalar mesons ($\pi, K, \eta$) off the ground-state charmed mesons ($D,D_s$) within chiral effective field theory. The recent lattice simulation results on various scattering lengths and the finite-volume spectra both in the moving and center-of-mass frames, most of which are obtained at unphysical meson masses, are used to constrain the free parameters in our theory. Explicit formulas to include the $S$- and $P$-wave mixing to determine the finite-volume energy levels are provided. After a successful reproduction of the lattice data, we perform a chiral extrapolation to predict the quantities with physical meson masses, including phase shifts, inelasticities, resonance pole positions and the corresponding residues from the scattering of the light pseudoscalar and charmed mesons.Comment: 32 pages, 9 figure

Small Momentum Evolution of the Extended Drell--Hearn--Gerasimov Sum Rule

We investigate the momentum dependence of the extended Drell-Hearn-Gerasimov sum rule. An economical formalism is developed which allows to express the extended DHG sum rule in terms of a single virtual Compton amplitude in forward direction. Rigorous results for the small momentum evolution are derived from chiral perturbation theory within the one-loop approximation. Furthermore, we evaluate some higher order contributions arising from $\Delta(1232)$ intermediate states and relativistic corrections. (2 figures available upon request).Comment: 12 pages, TeX, BUTP-92/51 and CRN-92-5

The Nucleon Anapole Moment and Parity-Violating ep Scattering

Parity-violating (PV) interactions among quarks in the nucleon induce a PV $\gamma NN$ coupling, or anapole moment (AM). We compute electroweak gauge-independent contributions to the AM through {\cal O}(1/\lamchis) in chiral perturbation theory. We estimate short-distance PV effects using resonance saturation. The AM contributions to PV electron-proton scattering slightly enhance the axial vector radiative corrections, R_A^p, over the scale implied by the Standard Model when weak quark-quark interactions are neglected. We estimate the theoretical uncertainty associated with the AM contributions to R_A^p to be large, and discuss the implications for the interpretation PV of ep scattering.Comment: RevTex 29 pages + 8 PS figures, references and discussions added, to appear in Phys. Rev.