arXiv subjects

Chung Wen Kao

Publications and source records attributed to Chung Wen Kao.

23 records · Page 2Linked to original sources

arXiv2002

Burkhardt-Cottingham sum rule and forward spin polarizabilities in Heavy Baryon Chiral Perturbation Theory

We study spin-dependent sum rules for forward virtual Compton scattering(VVCS) off the nucleon in heavy baryon chiral perturbation theory at order $O(p^4)$. We show how these sum rules can be evaluated from low energy expansions (in the virtual photon energy) of the forward VVCS amplitudes. We study in particular the Burkhardt -Cottingham sum rule in HBChPT and higher terms in the low energy expansion, which can be related to the generalized forward spin polarizabilities of the nucleon. The dependence of these observables on the photon virtuality $Q^2$ can be accessed, at small and intermediate $Q^2$ values, from existing and forthcoming data at Jefferson Lab.

hep-ph↗

arXiv2001

Quark effects and isospin-violation in ${}1S_0$ NN scattering

We present the results of the effects of various mechanisms on the quark level, including QED-QCD interference effect, on isospin violation in ${}1S_0$ NN scatterings with the new sets of strength parameters obtained by fitting to mass splittings in the baryon isomultiplets listed in the most recent PDG compilation. We also give the matrix elements of the various potential operators which would be useful to study of these charge dependent effects in finite nuclei.

nucl-th↗

arXiv2000

Parity Violation in Polarized-Gamma Proton Compton Scattering

Polarized beam gamma p Compton scattering provides a theoretically clean way to extract the isovector parity violating pion-nucleon coupling constant $h_{πNN}^{(1)}$. This channel is more tractable experimentally than the recently proposed extraction of $h_{πNN}^{(1)}$ from the Bedaque-Savage process --- polarized target gamma p compton scattering. The leading parity violating effect is calculated using Heavy Baryon Chiral Perturbation Theory. The size of the asymmetry is estimated to be ~ 4 10^{-8} for 120 MeV photon energy.

nucl-th↗

arXiv1999

The Pion Electroproduction in the $Δ$(1232) region region

The amplitudes of the pion electroproduction from the nucleon are derived up to third order in the chiral effective theory including explicit $Δ$(1232) >. The Q^2 evolutions of weighted integrals of amplitudes are presented.

nucl-th↗

arXiv1999

The pion photoproduction in the Δ(1232) region

We investigate the pion photoproduction in the Δ(1232) region in the framework of an effective Lagrangian including pions, nulceon and Δ(1232). We work to third order in a small scale expansion with both $m_π$ and $M_Δ-M_N$ treated as light scales. We note that in the $Δ$ region, straightward power counting breaks as the amplitudes become very large, to deal with this problem, we suggest that the appropriate way to compare theoretical calculations with experimental data is via weighted integrals of the amplitudes through the $Δ$ region.

nucl-th↗