相关论文: N Delta - Transition Form Factors at Low Momentum …
We consider the electromagnetic transition form factors of the Roper resonance in the framework of an effective field theory of pions, nucleons and delta and Roper resonances as explicit degrees of freedom. Due to the lack experimental data…
We report a new measurement of the exclusive electroproduction reaction gamma* p -> pi0 p to explore the evolution from soft non-perturbative physics to hard processes via the Q2 dependence of the magnetic (M1+), electric (E1+) and scalar…
A covariant quark model, based both on the spectator formalism and on vector meson dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra…
We review the description of the lowest-energy nucleon excitation -- the $\Delta$(1232)-resonance. Much of the recent experimental effort has been focused on the precision measurements of the nucleon-to-$\Delta$ transition by means of…
The four N to $\Delta$ axial transition form factors are evaluated using quenched QCD, using two flavors of dynamical Wilson fermions and using domain wall valence fermions on three-flavor MILC configurations for pion masses down to 360…
Within the framework of QCD light-cone sum rules (LCSR), we calculate the form factor for $B{\to}D l\tilde{\nu}$ transitions with chiral current correlator. The resulting form factor depends on the distribution amplitude(DA) of the…
The low-energy chiral effective field theory of vector mesons and Goldstone bosons in external gravitational field is considered. The energy-momentum tensor is obtained and the gravitational form factors of the $\rho$-meson are calculated…
Using dispersion theory, the electromagnetic Sigma-to-Lambda transition form factors are expressed as the product of the pion electromagnetic form factor and the $\Sigma\bar{\Lambda}\to\pi\pi$ scattering amplitudes with the latter estimated…
Lattice results on the N to Delta electromagnetic, axial-vector and pseudoscalar form factors are evaluated using dynamical staggered sea quarks and domain wall valence quarks for pion masses in the range of 580-350 MeV, as well as,…
The gravitational form factors of the transition from the proton to the $\Delta^+$ resonance are calculated to leading one-loop order using a manifestly Lorentz-invariant formulation of chiral perturbation theory. We take into account the…
We employ the quark part of the symmetric energy-momentum tensor current to calculate the transition gravitational form factors of the $N(1535) \rightarrow N$ by means of the light cone QCD sum rule formalism. In numerical analysis, we use…
The $\Delta(1232) \to \gamma^\ast N$ magnetic dipole form factor ($G_M^\ast$) is described here within a new covariant model that combines the valence quark core together with the pion cloud contributions. The pion cloud term is…
Weak transition form factors among heavy pseudoscalar mesons are investigated within a relativistic quark model formulated on the light-front. It is shown that the light-front result derived in the time-like region for the matrix elements…
We study the form factors for semileptonic decays of $D$-mesons. That is, we consider the matrix element of the weak left-handed quark current for the transitions $D \rightarrow P$ and $D \rightarrow V$, where $P$ and $V$ are light…
We develop a methodology that enables us to extract accurately the electromagnetic Delta form factors and their momentum dependence. We test our approach in the quenched approximation as a preparation for a study using dynamical fermions.…
We have studied the $P\to\gamma^\star\gamma^\star$ form factor in Resonance Chiral Theory, with $P = \pi^0,\eta,\eta'$, to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic…
The EM ratio for a free Delta electromagnetic transition is discussed within the frame work of nonrelativistic approach. Such an approach gives a good account of data for a free Delta but is less important for an intrinsically relativistic…
We calculate magnetic moments of light baryons and N -> Delta gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a cloud of…
We evaluate the N to Delta axial transition form factors in lattice QCD in the quenched theory, with two degenerate flavors of dynamical Wilson fermions and using domain wall valence fermions with staggered sea quark configurations. We…
We study the transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing the light-front calculation in the $q^+ =0$ frame in parallel with the manifestly…