Spectrum and Structure of Excited Baryons with CLAS

Abstract

In this contribution we discuss recent results in light quark baryon spectroscopy involving CLAS data and higher level analysis results from the partial wave analysis by the Bonn-Gatchina group. New baryon states were discovered largely based on the open strangeness production channels $\gamma p\to K^{+}\Lambda$ and $\gamma p\to K^{+}{\Sigma }^0$. The data illustrate the great potential of the kaon-hyperon channel in the discovery of higher mass baryon resonances in s-channel production. Other channels with discovery potential, such as $\gamma p\to p\omega$ and $\gamma p\to \varphi p$ are also discussed. In the second part I will demonstrate on data the sensitivity of meson electroproduction to expose the active degrees of freedom underlying resonance transitions as a function of the probed distance scale. For several of the prominent excited states in the lower mass range the short distance behavior is described by a core of three dressed-quarks with running quark mass, and meson-baryon contributions make up significant parts of the excitation strength at large distances. Finally, an outlook is given of baryon resonance physics at the 12 GeV CEBAF electron accelerator.

arXiv comment11 pages, 21 figures

References in corpus (45)

• Big-Bang Nucleosynthesis
• Excited state baryon spectroscopy from lattice QCD
• Properties of baryon resonances from a multichannel partial wave analysis
• Explanation and Prediction of Observables using Continuum Strong QCD
• Differential Cross Sections for gamma + p --> K+ + Y for Lambda and Sigma0 Hyperons
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Nucleon resonances within a dynamical coupled-channels model of pi N and gamma N reactions
• Additional Strange Hadrons from QCD Thermodynamics and Strangeness Freeze-out in Heavy Ion Collisions
• Electroexcitation of nucleon resonances
• Hyperon Photoproduction in the Nucleon Resonance Region
• Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab
• First Measurement of Beam-Recoil Observables Cx and Cz in Hyperon Photoproduction
• Disentangling the dynamical origin of P11 Nucleon Resonances
• A study of the $P_{11}(1440)$ and $D_{13}(1520)$ resonances from CLAS data on $ep\to e^{\prime }{\pi }^{+}{\pi }^{-}{p}^{\prime }$
• Nucleon and $\Delta$ elastic and transition form factors
• Completing the picture of the Roper resonance
• Hybrid Baryons in QCD
• The melting and abundance of open charm hadrons
• New Results from the Studies of the $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ Resonances in Exclusive $ep\to e^{\prime }{p}^{\prime }{\pi }^{+}{\pi }^{-}$ Electroproduction with the CLAS Detector
• Differential cross sections and recoil polarizations for the reaction gamma p -> K+ Sigma0
• Dynamical Coupled-Channels Effects on Pion Photoproduction
• Photocouplings at the Pole from Pion Photoproduction
• Electroexcitation of the Roper resonance for 1.7 < Q2 < 4.5 GeV2 in ep -> enpi+
• Nucleon electromagnetic form factors and electroexcitation of low lying nucleon resonances in a light-front relativistic quark model
• A systematic study of longitudinal and transverse helicity amplidutes in the hypercentral Constituent Quark Model
• Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction $\gamma p\to \varphi p$
• Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS
• Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega
• Cross sections and beam asymmetries for $\vev{e}p \to enπ^+$ in the nucleon resonance region for $1.7\le Q^2\le 4.5(GeV{)}^2$
• Photoproduction of $\Lambda$ and ${\Sigma }^0$ hyperons using linearly polarized photons
• A consistent explanation of the Roper phenomenology
• Empirical transverse charge densities in the nucleon-to-P11(1440) transition
• Measurements of $ep\to e^{\prime }{\pi }^{+}n$ at W = 1.6 - 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS
• Partial wave analysis of the reaction gamma p -> p omega$ and the search for nucleon resonances
• Do the $P_c^{+}$ Pentaquarks Have Strange Siblings?
• Electroproduction of p π^{+} π^{-} off protons at 0.2<Q^{2}<0.6 GeV^{2} and 1.3<W<1.57 GeV with CLAS
• Electroproduction of the Roper resonance on the proton: the role of the three-quark core and the molecular N-sigma component
• Electroproduction of the $N^{\ast }(1535)$ nucleon resonance in QCD
• $\varphi$-meson photoproduction on Hydrogen in the neutral decay mode
• Electromagnetic transition form factors of the Roper resonance in effective field theory
• Electroexcitation of the Delta(1232)3/2+ and Delta(1600)3/2+ in a light-front relativistic quark model
• Extracting meson-baryon contributions to the electroexcitation of the $N(1675){\frac{5}{2}}^{-}$ nucleon resonance
• Strangeness in the proton and N*(1535)
• Diquark Substructure in $\varphi$ Photoproduction
• Configuration mixings and light-front relativistic quark model predictions for the electroexcitation of the Delta(1232)3/2+, N(1440)1/2+, and Delta(1600)3/2+

Cited by in corpus (5)

• Photon beam asymmetry $\Sigma$ for $\eta$ and ${\eta }^{\prime }$ photoproduction from the proton
• Transition form factors and helicity amplitudes for electroexcitation of negative- and positive parity nucleon resonances in a light-front quark model
• Measurements of the ${\gamma }_{v}p\to p^{\prime }{\pi }^{+}{\pi }^{-}$ cross section with the CLAS detector for $0.4$ GeV${}^2$ $<Q^2<$ $1.0$ GeV${}^2$ and $1.3$ GeV $<W<$ $1.825$ GeV
• Photon beam asymmetry $\Sigma$ in the reaction $\vec{\gamma }p\to p\omega$ for $E_{\gamma }$ = 1.152 to 1.876 GeV
• New graphical criterion for the selection of complete sets of polarization observables and its application to single-meson photoproduction as well as electroproduction