相关论文: N Delta - Transition Form Factors at Low Momentum …
The proton to $\Delta^+$ resonance transitional gravitational form factors are calculated to leading one-loop order using chiral perturbation theory in our recent work [1]. We take into account the leading electromagnetic and strong…
The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be…
Within Chiral Perturbation Theory (CHPT) we compute the form factors A, V and $\gamma = A/V$ in the $\pi \to \nu l \gamma$ decay to $O(p^6)$. A and $\gamma$ obtain corrections of order 25%.
We calculate the electromagnetic form factors of the nucleon up to fourth order in manifestly Lorentz-invariant chiral perturbation theory with vector mesons as explicit degrees of freedom. A systematic power counting for the renormalized…
The form factors for the $B-->\pi$ transition are evaluated in the entire momentum transfer range by using the constraints obtained in the framework combining the heavy quark expansion and chiral symmetry for light quarks and the quark…
Previous calculations of the polarizabilities of the nucleon within the framework of heavy baryon chiral perturbation theory have included the contribution of the $\Delta$(1232) only its effect on various contact terms or have been…
The magnetic form factors of $^2$H, $^3$H, and $^3$He, deuteron photodisintegration cross sections at low energies, and deuteron threshold electrodisintegration cross sections at backward angles in a wide range of momentum transfers, are…
The exact form of the form-factor associated with a meson-photon-photon vertex is not known. Different suggestions exist, based on constraints from QCD and on recent experiments. Four different form-factors are studied in this article. We…
We analyze the low-$Q^2$ behavior of the axial form factor $G_A(Q^2)$, the induced pseudoscalar form factor $G_P(Q^2)$, and the axial nucleon-to-$\Delta$ transition form factors $C^A_5(Q^2)$ and $C^A_6(Q^2)$. Building on the results of…
I give a very short introduction to Chiral Perturbation Theory and an overview of the next-to-next-to-leading order three-flavour calculations done. I discuss those relevant for an improvement in the accuracy of the measurement of $V_{us}$…
We analyze the longest-range two-pion exchange contributions to the three-nucleon force at leading-loop order in the framework of heavy-baryon chiral effective field theory with explicit $\Delta(1232)$ degrees of freedom. All relevant…
We investigate the electromagnetic transition form factors of the baryon decuplet to the baryon octet, based on the self-consistent SU(3) chiral quark-soliton model, taking into account the effects of explicit breaking of flavor SU(3)…
The electromagnetic and axial form factors of the nucleon and its lowest positive parity excitations, the Delta(1232) and the N*(1440), are calculated with constituent-quark models that are specified by simple algebraic representations of…
We investigate the light-front zero-mode contribution to the weak transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. In particular, we discuss the form factors…
The transition form factor of a gamma into three pions $F_{3\pi}$ are studied in a framework of nonlocal chiral quark model. In local limit the result is agreement with chiral perturbative theory and reproduce Wess-Zumino-Witten anomaly.…
A systematic calculation for the transition form factors of heavy to light mesons ($B,B_s,D,D_s \to \pi, K, \eta, \rho, K^*, \omega, \phi$) is carried out by using light-cone sum rules in the framework of heavy quark effective field theory.…
A quark model relation between the neutron charge form factor and the N->Delta charge quadrupole form factor is used to predict the C2/M1 ratio in the N->Delta transition from the elastic neutron form factor data. Excellent agreement with…
I discuss recent work on nucleon form factors, magnetic strangeness in the nucleon and the isovector nucleon-delta transition based on the broken chiral symmetry of QCD, utilizing recent theoretical developments in ChPT.
Using the CLEO-II detector, we have measured the form factors associated with the electromagnetic transitions $\gamma^*\gamma \to $ meson. We have measured these form factors in the momentum transfer ranges from 1.5 to 9, 20, and 30 GeV^2…
We discuss form factors and coupling constants for the $\gamma^* \pi^0 \gamma$, $\rho\pi\pi$ and $\gamma \pi \rho$ interactions generated by a model field theory that produces finite size $\bar{q}q$ meson modes. The approach implements…