相关论文: Electroexcitation of nucleon resonances

The multipole amplitudes for the N - Delta electromagnetic transition are computed in the framework of the linear sigma model and the chiral chromodielectric model for small and moderate photon virtualities. The models include quark and…

For half a century, the Roper resonance has defied understanding. Discovered in 1963, it appears to be an exact copy of the proton except that its mass is 50% greater. The mass is the first problem: it is difficult to explain with any…

The sensitivity of the deuteron form factor to contributions from the excited states of the nucleon is explored using a simple model of the nucleon-nucleon interaction which employs a tower of charged nucleon resonances. The model is…

In this paper, we study the nucleon energy spectrum in the ground-state (with orbital momentum L=0) and the first excited state (L=1). The aim of this study is to find the mass and mixing angles of excited nucleons using a potential model…

Superscaling analyses of few-GeV inclusive electron scattering from nuclei are extended to include not only quasielastic processes, but now also into the region where $\Delta$-excitation dominates. It is shown that, with reasonable…

The 2H(p,n) charge exchange reaction at T_p=790 MeV is used to study the Delta(1232)-nucleon interaction in the Delta resonance excitation energy region. For the Delta-N potential, a meson exchange model is adopted where pi, rho, omega, and…

The $\Delta-N$ electromagnetic transition form factors are calculated in the Poincar\'e covariant quark model in three forms of relativistic kinematics. Addition of $D-$state components to pure $S-$state model wave functions, chosen so as…

New cross sections for the reaction $ep \to e'\eta p$ are reported for total center of mass energy $W$=1.5--2.3 GeV and invariant squared momentum transfer $Q^2$=0.13--3.3 GeV$^2$. This large kinematic range allows extraction of new…

The differential cross section for the process p(e,e'p)eta has been measured at Q^2 = 2.4 and 3.6 (GeV/c)^2 at center-of-mass energies encompassing the S11(1535) resonance. The latter point is the highest-Q^2 exclusive measurement of this…

We present a leading-order pQCD calculation of the helicity-flip $\Delta\to N\gamma^*$ matrix element $G_0$ (Coulomb quadrupole amplitude $C2$), taking into account the transverse momenta of the quarks and the contribution from the gluons.…

The so-called second resonance region of the nucleon comprises the states P11(1440), D13(1520) and S11(1535). During the last few years photoproduction experiments have largely contributed to a better understanding of these states, but the…

Two superconducting quarter-wave resonator (QWR) prototypes have been fabricated and tested. They operate at 80.5 MHz and 161 MHz and are optimised for beta = 0.085 and beta = 0.16, respectively. The prototypes are simplified versions…

We report a Cu $K$-edge resonant inelastic x-ray scattering (RIXS) study of charge-transfer excitations in the 2-8 eV range in the structurally simple compound HgBa$_2$CuO$_{4+\delta}$ at optimal doping ($T_{\rm c} = 96.5 $ K). The spectra…

Spectra of p-p and pi-p scattering at beam momenta between 6 and 30 GeV/c have been reanalysed. These show strong excitation of N* resonances, the strongest one corresponding to the "scalar" P11 excitation (breathing mode) at m_o= 1400+-10…

Electron-impact vi->vf vibrational excitations cross sections, involving rovibrationally excited N_{2}(v_{i}, J) and NO(v_{i}, J) molecules (fixed J), are calculated for collisions occurring through the nitrogen resonant electronic state…

We study electromagnetic transitions of excited baryons in a deformed oscillator quark model, where baryon excited states are described as rotational bands of deformed intrinsic states. We describe all necessary tools to compute transition…

We study the excited-state potential and the gluonic excitation in the static three-quark (3Q) system using SU(3) lattice QCD with $16^3\times 32$ at $\beta$=5.8 and 6.0 at the quenched level. For about 100 different patterns of…

Neutral current photon emission reactions with nucleons and nuclei are studied. These processes are important backgrounds for nu_mu to nu_e (bar(nu)_mu to bar(nu)_e) appearance oscillation experiments where electromagnetic showers…

We explore some properties of twin kilohertz quasiperiodic oscillations (QPOs) in a simple toy-model consisting of two oscillation modes coupled by a general nonlinear force. We examine resonant effects by slowly varying the values of 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…