相关论文: The Nucleon Structure in the Resonance Region
Results of the recently developed unitary isobar model (MAID) are presented for the spin asymmetries, structure functions and relevant sum rules in the resonance region. The model describes the presently available data for single-pion…
Electroproduction of neutral pions in exclusive reaction $p(e,e'\pi^0)p$ is studied above the resonance region, $\sqrt{s}>2$ GeV. The reaction amplitude is described by exchanges of vector $\omega(782)$, $\rho(770)$ and axial-vector…
Dimuon production has been studied in a series of fixed-target experiments at Fermilab during the last two decades. Highlights from these experiments, together wih recent results from the Fermilab E866 experiment, are presented. Future…
We summarize the experimental program of Jefferson Lab that studies the nucleon spin structure at low $Q^2$. This program completes the precise experimental mapping of the nucleon spin structure functions $g_1(\nu, Q^2)$ and $g_2(\nu, Q^2)$…
The concepts of Generalized Parton Distributions (GPD) are reviewed in an introductory and phenomenological fashion. These distributions provide a rich and unifying picture of the nucleon structure. Their physical meaning is discussed. The…
A pedagogical summary of current and past experimental results of spin-dependent nucleon structure prior to the arrival of the Electron-Ion Collider is attempted. After an introduction, results from fixed-target experiments at SLAC,…
Photo- and electroproduction of pions and eta-mesons is studied on the nucleon. The formalism of such reactions is presented including polarization degrees of freedom and theoretical approaches are discussed. In particular, the threshold…
Exploiting the isobar model, kaon photo- and electroproduction on the proton in the resonance region comes under scrutiny. An upgrade of our previous model, comprising higher-spin nucleon and hyperon exchanges in the consistent formalism,…
A large fraction of the world data on both polarized and unpolarized inclusive $ep$ scattering at large Bjorken $x$ lies in the resonance region where a correspondence with the deep inelastic regime, known as Bloom and Gilman's duality, was…
The single-differential and fully integrated cross sections for quasifree $\pi^{+}\pi^{-}$ electroproduction off protons bound in deuterium have been extracted for the first time. The experimental data were collected at Jefferson Laboratory…
The current status of global QCD analysis of parton distribution functions of the nucleon is reviewed. Recent progress made in determining various features of the parton structure of the nucleon, as well as outstanding open questions are…
Differences in the photoproduction of mesons on the free proton and on nuclei are expected to reveal changes in the properties of hadrons. Inclusive studies of nuclear photoabsorption have provided evidence of medium modifications. However,…
At the energies of present and future electron accelerators designed to study the structure of hadrons, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process in QCD. The process is not the…
Physics perspectives are shown for future experiments in electron or positron scattering on nucleons, towards a deep and comprehensive understanding of the angular momentum structure of the nucleon in the context of Quantum Chromodynamics.…
High quality polarized electron beams at Jefferson Lab make possible precision measurements of hadronic properties in the regime of strongly interacting QCD. We will describe a few programs at Jefferson Lab that are making measurements that…
Over the past decade, new data from HERMES, Jefferson Lab, Fermilab, and RHIC that connect to parton propagation and hadron formation have become available. Semi-inclusive DIS on nuclei, the Drell-Yan reaction, and heavy-ion collisions all…
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has been greatly improved by performing double polarization experiments, in…
Exclusive electroproduction of a K or K* meson on the nucleon can give a Theta+ pentaquark in the final state. This reaction offers an opportunity to investigate the structure of pentaquark baryons at parton level. We discuss the…
The exclusive electroproduction process $ep \rightarrow e'p'\pi^{0}$ was measured in the range of photon virtualities $Q^{2} = 0.4 - 1.0$~GeV$^{2}$ and the invariant mass range of the $p\pi^{0}$ system of $W = 1.1 - 1.8$~GeV. These…
This document outlines major directions in theoretical support for the measurement of nucleon resonance transition form factors at the JLab 12 GeV upgrade with the CLAS12 detector. Using single and double meson production, prominent…