相关论文: Electromagnetic structure of the nucleon and the R…
A parameter-free evaluation of the $N - P_{11}(1440)$ electromagnetic transition form factors is performed within a light-front constituent quark model, using for the first time the eigenfunctions of a mass operator which generates a large…
The application of relativistic constituent quark models to the evaluation of the electromagnetic properties of the nucleon and its resonances is addressed. The role of the pair creation process in the Feynmann triangle diagram is discussed…
We study electromagnetic properties of the nucleon and Roper resonance in a chiral quark-diquark model including two kinds of diquarks needed to describe the nucleon: scalar and axial-vector diquarks. The nucleon and Roper resonance are…
The Roper resonance is considered as a mixed state of a three-quark core configuration and a hadron molecular component N+sigma. Based on this ansatz we study electroproduction of the Roper resonance. The strong and electromagnetic…
Recent measurements of nucleon resonance transition form factors with CLAS at Jefferson Lab are discussed. The new data resolve a long-standing puzzle of the nature of the Roper resonance, and confirm the assertion of the symmetric…
Current matrix elements and observables for electro- and photo-excitation of baryons from the nucleon are studied in a light-front framework. Relativistic effects are examined by comparison to a nonrelativistic model and can typically be of…
The momentum distributions of the constituent quarks inside the nucleon and the prominent electroproduced nucleon resonances are investigated in the two most sophisticated, available quark potential models, based respectively on the…
The second excitation of the nucleon, the Roper, has properties differentiated from other low-lying nucleon resonances. Their properties challenge our understanding of the structure of the baryons in terms of the degrees of freedom from…
We compute the Euclidean hadronic tensor from charge density operators and extract elastic and resonance structures by employing exponential fits to the four-point correlator, as well as a Bayesian reconstruction inverse algorithm to obtain…
We calculate the electroweak properties of nucleons and hyperons in a relativistic constituent quark model using the light-front formalism. The parameters of the model, namely the constituent quark mass and the confinement scale, can be…
We present an improved study of the electromagnetic form factors of the nucleon and of the Roper-nucleon transition using an extended version of the effective action of soft-wall AdS/QCD. We include novel contribution from additional…
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…
The elastic and transition electromagnetic form factors of mesons are investigated within a light-front constituent quark model. The general formulae for the space-like matrix elements of the one-body component of the electromagnetic…
We perform a calculation of the relativistic corrections to the electromagnetic elastic form factors of the nucleon obtained with various Constituent Quark Models. With respect to the non relativistic calculations a substantial improvement…
We study the elastic electric and magnetic form factors of the proton, neutron and the charged roper resonance ($G_E^p$, $G_M^p$, $G_E^n$, $G_M^n$, $G_E^R$ and $G_M^R$) systematically in a constituent quark model. Three ingredients are…
The recently proposed mechanism for the formation of the Roper resonance, in which a dynamically generated state as well as a genuine three-quark resonant state play an equally important role, is confronted with the model proposed almost…
The electroweak properties of nucleons and hyperons are calculated in a relativistic constituent quark model. The baryons are treated as three quark bound states, and the diagrams of perturbation theory are considered on the light front.…
The electromagnetic form factors of the $\rho$ meson are evaluated adopting a relativistic constituent quark model based on the light-front formalism, and using a meson wave function with the high-momentum tail generated by the…
We compute nucleon and Roper e.m. elastic and transition form factors using a symmetry-preserving treatment of a contact-interaction. Obtained thereby, the e.m. interactions of baryons are typically described by hard form factors. In…
We investigate the electric form factors of the nucleon and Roper resonance using a quark-diquark model. We find that the charge radii of the nucleon and Roper resonance are almost the same in size.