相关论文: $\gamma N \to N^*(1535)$ transition in soft-wall A…
The helicity amplitudes of the $N(1520)$ and $N(1535)$ resonances in the $\gamma^*p\to N^*$ electromagnetic transition are studied in the constituent quark model using the impulse approximation, with the proton and resonances assumed to be…
We investigate the helicity amplitudes of the $N(1520)$ and $N(1535)$ resonances in the electromagnetic transition process $\gamma^*p\to N^*$, where the $N(1520)$ and $N(1535)$ are assumed to include both the $L=1$ three-quark and $L=0$…
The helicity amplitudes $A^{p}_{1/2}$ and $S^{p}_{1/2}$ for the electromagnetic transition $\gamma^{*} N\to N^{*}(1535)$ are calculated in the quark model that is extended to include the lowest lying $qqqq\bar{q}$ components in addition to…
The form factors, as well as the helicity amplitudes for the $\gamma^\ast N \to N(1535)$ transition are calculated in framework of the QCD light cone sum rules. The contamination coming from diagonal transition is eliminated by considering…
We discuss how electromagnetic properties provide useful tests of the nature of resonances, and we study these properties for the N*(1535) which appears dynamically generated from the strong interaction of mesons and baryons. Within this…
It is shown that the helicity amplitudes A_1/2 and S_1/2 in the gamma N -> N(1535) reaction, can be well related by S_1/2 = -\frac{\sqrt{1+\tau}}{\sqrt{2}} \frac{M_S^2-M^2}{2 M_S Q} A_1/2 in the region Q^2 > 2 GeV^2, where M and M_S are the…
The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7 < Q2 < 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for pi+ electroproduction on…
Using the recent precise measurements of eta photopro- duction in proton and deuteron targets, we extract the ratio of the helicity amplitudes A^n_1/2 / A^p_1/2, for the excitation of N^*(1535), in the effective Lagrangian approach, It is…
A relativistic constituent quark model is applied to the gamma N -> N(1535) transition. The N(1535) wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the S11 resonance.…
We modified the current soft wall model by considering the Non-conformal aspect low energy QCD.
The $\gamma^\ast N \to N^\ast (1520)$ reaction is studied in framework of the light cone QCD sum rules method. The sum rules for the multipole form factors, namely, for the magnetic dipole $G_M(Q^2)$, electric quadrupole $G_E(Q^2)$, and…
A workable basis of quark configurations $s^3$, $s^2p$ and $sp^2$ at light front has been constructed to describe the high-$Q^2$ behavior of transition form factors and helicity amplitudes in the electroproduction of the lightest nucleon…
A covariant spectator quark model is applied to study the gamma N -> N*(1535) reaction in the large Q2 region. Starting from the relation between the nucleon and N*(1535) systems, the N*(1535) valence quark wave function is determined…
Some empirical parametrizations of the $\gamma^\ast N \to N(1535)$ transition amplitudes violates the Siegert's theorem, that relates the longitudinal and the transverse amplitudes, in the pseudo-threshold limit (nucleon and resonance at…
The helicity amplitudes for the transitions $N-S_{11}$ and $N-S_{31}$ are presented. The amplitudes have been obtained within our front-form CQM model, based on hadron eigenstates of a relativistic mass operator and CQ current with Dirac…
We report on the first lattice calculation of light-cone distribution amplitudes of the N*(1535) resonance, which are used to calculate the transition form factors at large momentum transfers using light-cone sum rules. In the region Q^2 >…
We present predictions for the $\gamma^\ast N \to N^\ast$ helicity amplitudes, where $N^\ast$ is a member of the $[70,1^-]$ supermultiplet. We combine the results from the single quark transition model for the helicity amplitudes with the…
The $\gamma^\ast N \to N(1520)$ transition has a property that differs from the other low-lying nucleon resonance amplitudes: the magnitude of the transverse helicity amplitudes.The transition helicity amplitudes are defined in terms of…
We present a study of electroexcitation of nucleon resonances with higher spins, in a soft-wall AdS/QCD model, comparing our results with existing data from the CLAS Collaboration at JLab, from MAMI, and other experiments.
We investigate the electroproduction of eta mesons below a center of momentum energy of 1.6 GeV, with particular emphasis on the roles of the N*(1535) and N*(1520) resonances. Using the effective Lagrangian approach, we show that the…