Shi-Lin Zhu

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 O(1/{lambda}{sub {chi}}{sup 2}) 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{sub A}{sup 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{sub A}{sup p} to be large, and discuss the implications for the interpretation PV of ep scattering. (c) 2000 The American Physical Society.

Recoil order chiral corrections to baryon octet axial vector currents

We calculate chiral corrections to the octet axial currents through

Octet baryon charge radii, chiral symmetry and decuplet intermediate states

{\cal O}(p^3)

Strong and electromagnetic decays ofp-wave heavy baryonsΛc1,Λc1*

using baryon chiral perturbation theory (BCPT). The relativistic BCPT framework allows one to sum an infinite series of recoil corrections at a given order in the chiral expansion. We also include SU(3)-breaking operators occuring at

What do we know about the strange magnetic radius

{\cal O}(p^2)

Electroweak radiative corrections to parity-violating electroexcitation of the Delta

not previously considered. We determine the corresponding low-energy constants (LECs) from hyperon semileptonic decay data using a variety of infrared regularization schemes. We find that the chiral expansion of the axial currents does not display the proper convergence behavior, regardless of which scheme is chosen. We explore the implications of our analysis for determinations of the strange quark contribution to the nucleon spin,

Recoil order chiral corrections to baryon octet axial vector currents and large Nc QCD

\Delta s

Chiral symmetry and the parity-violating NN pi Yukawa coupling

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Subleading corrections to parity-violating pion photoproduction

We compute the octet baryon charge radii to O(1/{Lambda}{sub {chi}}{sup 2}M{sub N}) in heavy baryon chiral perturbation theory (HB{chi}PT). We examine the effect of including the decuplet of spin-3/2 baryons explicitly. We find that it does not improve the level of agreement between the HB{chi}PT and experimental values for the {Sigma}{sup -} charge radius.

Off-diagonal Goldberger-Treiman relation and its discrepancy

We first calculate the binding energy, the pionic and electromagnetic couping constants of the lowest lying p-wave heavy baryon doublet