相关论文: Dressing the electromagnetic nucleon current
A didactic and systematic derivation of Noether point symmetries and conserved currents is put forward in special relativistic field theories, without a priori assumptions about the transformation laws. Given the Lagrangian density, the…
Photo- and electroproduction of pions and eta-mesons is studied on the nucleon. The formalism of such reactions is presented including polarization degrees of freedom and theoretical approaches are discussed. In particular, the threshold…
Mathematical ambiguities in partial-wave analysis present a significant challenge to the extraction of resonance properties in hadronic reactions. Recent work has shown that while linear photon polarization can resolve continuous…
Low-energy eta photoproduction on the nucleon is studied in an effective Lagrangian approach that contains Born terms, vector meson and nucleon resonance contributions. The resonance sector includes the $S_{11}(1535)$, $P_{11}(1440)$ and…
Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, $\Delta$ isobars, and pions up to N$^2$LO, {\it i.e.} ignoring loop corrections, are used in a study of neutron radiative…
The parity and time-reversal invariant effective lagrangian for a heavy fermion interacting with an abelian gauge field, i.e., NRQED, is constructed through order $1/M^4$. The implementation of Lorentz invariance in the effective theory…
Recently, we have derived a two--nucleon potential and consistent nuclear electromagnetic currents in chiral effective field theory with pions and nucleons as explicit degrees of freedom. The calculation of the currents has been carried out…
We investigate photoproduction of the scalar mesona off the nucleon, using the effective Lagrangians and the Regge approach. We first study $f_0(980)$ photoproduction, replacing the Feynman propagator with the Regge ones for the…
A new operator for pion photo- and electroproduction has been developed for nuclear applications at photon equivalent energies up to 1 GeV. The model contains Born terms, vector mesons and nucleon resonances ($P_{33}(1232)$, $P_{11}(1440)$,…
We show how effectively effective quantum field theories work in nuclear physics. Using the physically transparent cut-off regularization, we study the simplest nuclear systems of two nucleons for both bound and scattering states at a…
The meson-exchange current in nuclei, a long-standing problem in nuclear physics, is described in modern theory of strong interactions, namely, QCD expressed in terms of effective chiral Lagrangian field theory. Some old results are given a…
We present a comparative study of the pion induced production of $K^0 \Lambda$ and $D^- \Lambda_c^+$ off the nucleon. A hybrid framework is utilized by combining an effective Lagrangian method with a Regge approach. We consider the…
A nonrelativistic effective theory to describe the electroproduction reaction of a single pion on the nucleon at leading order in the electromagnetic coupling is constructed. The framework is tailored to accurately describe the cusp…
A field-theoretic parametrization is proposed for nucleon electromagnetic form factors at momentum transfer less than 600 MeV. The parametrization is part of a larger effective field theory lagrangian that is Lorentz covariant and chirally…
A dynamical model based on effective Lagrangians is proposed to describe the bremsstrahlung reaction $ \pi N \to \pi N \gamma$ at low energies. The $\Delta(1232)$ degrees of freedom are incorporated in a way consistent with both,…
The photo- and electroproduction of eta, eta-prime mesons on nucleons are investigated within a relativistic chiral unitary approach based on coupled channels. The s-wave potentials for electroproduction and meson-baryon scattering are…
A model for the description of photonuclear reactions in the multi-GeV range is described that combines the coherent initial state interactions (shadowing) of the incoming photon with an incoherent coupled channel description of final state…
Pionless effective field theory with dibaryon fields is reexamined for observables involving the deuteron. The electromagnetic form factors of the deuteron and the total cross sections of radiative neutron capture on the proton, $np \to…
Meson production on the proton is described in a coupled channels K-matrix approach. Both hadronic and photonic scenarios are taken into account on the same theoretical footing. At tree-level the Born amplitudes are obtained from an…
The quasielastic charged current (CCQE) $\nu_e n \rightarrow e^- p$ scattering is the dominant mechanism to detect appearance of a $\nu_e$ in an almost $\nu_\mu$ flux at the 1 GeV scale. Actual experiments show a precision below 1% and…