Joachim Kambor

Heavy baryon chiral perturbation theory with light deltas

We demonstrate how heavy mass methods, previously applied to chiral perturbation theory calculations involving the interactions of nucleons and pions, can be generalized to include interactions with the ∆(1232).

Systematic 1/M expansion for spin 3/2 particles in baryon chiral perturbation theory

Abstract Starting from a relativistic formulation of the pion-nucleon-delta system, the most general structure of 1 M corrections for a heavy baryon chiral lagrangian including spin 3 2 resonances is given. The heavy components of relativistic nucleon and delta fields are integrated out and their contributions to the next-to-leading order lagrangians are constructed explicitly. The effective theory obtained admits a systematic expansion in terms of soft momenta, the pion mass mπ and the delta-nucleon mass difference Δ. As an application, we consider neutral pion photoproduction at threshold to third order in this small scale expansion.

Decay constants, light quark masses, and quark mass bounds from light quark pseudoscalar sum rules

The flavor

Strange quark mass from flavor breaking in hadronic τ decays

ud

Delta(1232) and the polarizabilities of the nucleon

and

On the longitudinal contributions to hadronic tau decay

us

Dispersion relations and soft pion theorems for K→ππ

pseudoscalar correlators are investigated using families of finite energy sum rules (FESRs) known to be very accurately satisfied in the isovector vector channel. It is shown that the combination of constraints provided by the full set of these sum rules is sufficiently strong to allow determination of both the light quark mass combinations

Dispersive approach to semileptonic form-factors in heavy to light meson decays

m_u+m_d

K(S)-)GAMMA-GAMMA, K(L)- )PI(0)GAMMA-GAMMA AND UNITARITY

,

A note on the dispersive treatment of K→ππ with the kaon off-shell

m_s+m_u