Related papers: Parity violating pion electroproduction off the nu…
We present a pion photoproduction model on the free nucleon based on an Effective Lagrangian Approach (ELA) which includes the nucleon resonances ($\Delta(1232)$, N(1440), N(1520), N(1535), $\Delta (1620)$, N(1650), and $\Delta (1700)$), in…
Parity violating (PV) effects in neutron-deuteron radiative capture are studied using Desplanques, Donoghue, and Holstein (DDH) and effective field theory weak potentials. The values of PV effects are calculated using wave functions,…
Parity violation in low-energy nuclear observables is included in the pionless effective field theory. The model-independent relation between the parity-violating asymmetry in polarized np -> d gamma and the non-nucleon part of the deuteron…
Photoproduction of two pions on nucleon and deuteron is studied for photon energies from threshold up to $E_\gamma = 1.5$ GeV. For the elementary operator an effective Lagrangean approach is used with resonance and Born contributions. The…
We show that polarized gamma p -> \pi^+ n in the threshold region is an excellent candidate for measuring the leading parity-violating pion-nucleon coupling h_{\pi NN}^{(1)} to an uncertainty of 20% if it has a natural size from dimensional…
The confirmation of the existence of GZK cut-off was tortuous, leading to activities to explore new physics, such as the cosmic-ray new components, unidentified cosmic-ray origins, unknown propagation mechanism, and the modification of…
In this work, an improved quark model approach to the $\omega$ meson photoproduction with an effective Lagrangian is reported. The {\it t}-channel {\it natural} parity exchange is consistently taken into account through the Pomeron…
We study the effects of the $\Delta$(1232) resonance as an effective degree of freedom for charged and neutral pion photo-production on nucleons. Different observables have been calculated for these processes by using relativistic chiral…
We shall review here our current knowledge and new frontiers of the pion photoproduction study, from threshold through the Delta resonance region, emphasizing the hadron physics program, of interest to a 250 MeV, high duty factor electron…
The electroweak interaction at the level of quarks and gluons are well understood from precision measurements in high energy collider experiments. Relating these fundamental parameters to Hadronic Parity Violation in nuclei however remains…
Phenomenological Lagrangians and dimensional power counting are used to assess isospin violation in the nucleon-nucleon force. The $\pi NN$ coupling constants (including the Goldberger-Treiman discrepancy), charge-symmetry breaking, and…
We construct the complete SU(2) parity-violating (PV) $\pi, N, \Delta$ interaction Lagrangian with one derivative, and calculate the chiral corrections to the PV Yukawa $NN\pi$ coupling constant $h_\pi$ through ${\cal O}(1/\Lambda_\chi^3)$…
Pion-nucleon scattering, pion photoproduction, and nucleon Compton scattering are analyzed within a scheme based on the chiral Lagrangian. Partial-wave amplitudes are obtained by an analytic extrapolation of subthreshold reaction amplitudes…
In this work, the $\eta^\prime$ meson photoproduction near threshold is studied in the quark model framework. A pseudovector effective Lagrangian is introduced for the $\eta^\prime NN$ coupling and the newly published data from the SAPHIR…
Particle production of an Abelian vector boson field with an axial coupling is investigated. The conditions for the generation of scale invariant spectra for the vector field transverse components are obtained. If the vector field…
In this report we have studied the implication of a parity and charge-parity (PCP) violating interaction in varying alpha theory. Due to this interaction, the state of photon polarization can change when it passes through a strong…
We present a detailed quark-model study of pion photoproduction within the effective Lagrangian approach. Cross sections and single-polarization observables are investigated for the four charge channels, $\gamma p\to \pi^+ n$, $\gamma n\to…
We report on parity-violating asymmetries in the nucleon resonance region measured using $5 - 6$ GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry…
In this work, we perform a study of nucleon resonance production in the $\gamma p \to p\eta\phi$ reaction within an effective Lagrangian approach. In our model, we consider the excitation of the $N^*(1535)$, $N^*(1650)$, $N^*(1710)$ and…
Polarization transfer (PT) observables in the single pion production induced by the charged current interaction of the neutrino with the nucleon are examined. The polarization components of the final nucleon and the charged lepton are…