Harold W. Fearing

Extension of the chiral perturbation theory meson Lagrangian to order p(6)

We have constructed the most general chirally invariant Lagrangian {ital scrL}{sub 6} for the meson sector at order {ital p}{sup 6}. The result provides an extension of the standard Gasser-Leutwyler Lagrangian {ital scrL}{sub 4} to one higher order, including as well all the odd intrinsic parity terms in the Lagrangian. The most difficult part of the construction was developing a systematic strategy so as to get all of the independent terms and eliminate the redundant ones in an efficient way. The claim to have obtained the most general Lagrangian relies on this systematic construction and on the elimination of redundant quantities using relations of which we are aware, rather than on a general formal proof of either completeness or independence. The {open_quote}{open_quote}equation-of-motion{close_quote}{close_quote} terms, which are redundant in the sense that they can be transformed away via field transformations, are separated out explicitly. The resulting Lagrangian has been separated into groupings of terms contributing to increasingly more complicated processes, so that one does not have to deal with the full result when calculating {ital p}{sup 6} contributions to simple processes. {copyright} {ital 1995 The American Physical Society.}

The form factors of the nucleon at small momentum transfer

Abstract We study the low energy expansion of the nucleons electroweak form factors in the framework of an effective chiral Lagrangian including pions, nucleons and the Δ(1232). We work to third order in the so-called small scale expansion and compare the results with the ones previously obtained in the chiral expansion. In addition, these calculations serve as a first exploratory study of renormalization and decoupling within the small scale expansion.

Induced pseudoscalar coupling of the proton weak interaction

The induced pseudoscalar coupling

Muon capture by a proton in heavy baryon chiral perturbation theory

{g}_{p}

Anomalous chiral perturbation theory meson Lagrangian to order p 6 reexamined

is the least well known of the weak couplings of the protons charged-current interaction. Its size is dictated by chiral symmetry arguments, and its measurement represents an important test of quantum chromodynamics at low energies. Experiments over the past decade have produced a large body of new data relevant to the coupling

Determination of the nucleon pseudoscalar coupling using muon capture by 3He

{g}_{p}.

Field transformations and simple models illustrating the impossibility of measuring off-shell effects

These data include measurements of radiative and nonradiative muon capture on targets ranging from hydrogen and few-nucleon systems to complex nuclei. The authors review the theoretical underpinnings of

Pion production in nuclei: Things known and unknown

{g}_{p},

Field transformations and the classical equation of motion in chiral perturbation theory

the experimental studies, and the procedures and uncertainties in extracting the coupling from data. They also discuss current puzzles and future opportunities.

Delta excitation and exchange corrections for NN bremsstrahlung.

The matrix element for muon capture by a proton is calculated to