γvNN^* Transition Amplitudes and Excited Baryon Structure from CLAS
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Studying excited nucleon structure through exclusive-meson electroproduction reactions is key for understanding the nature of the strong interaction in the non-perturbative regime. With its nearly complete coverage of the final-state phase space, the CLAS detector at JLab has provided the lion's share of the world's meson-electroproduction data for differential cross sections and the asymmetries arising from single- and double-polarization observables. Electrocouplings for most of the excited nucleon states (N*) in mass range of up to 1.8~GeV have been determined from several analyses of the CLAS data for photon virtualities (Q2) up to 5.0 GeV2 for the pi+n, pi0p, and eta p channels [1,3] as well as for the pi+pi-p reaction for Q2<1.5~GeV2 [2,3]. Physics analyses of these N* electrocouplings [2,3] have revealed that the structure of excited nucleon is formed of an internal core of dressed quarks with an external meson-baryon cloud. Our N*-electrocoupling results afford access to the non-perturbative strong interaction responsible for generating the different N* states and will also provide testing ground for the inspired by QCD quark model predictions. A dedicated experiment will run after the 12 GeV upgrade to JLab on the extraction of the N* electrocouplings in the yet unexplored region of high photon virtualities ranging from 5.0 to 12 GeV2. The anticipated results are of particular importance in providing a understanding of the nature of confinement and dynamical chiral symmetry breaking in baryons based upon the QCD [3].\\[4pt] [1] I.G. Aznauryan and V.D. Burkert, Prog. Part. Nucl. Phys. \textbf{67}, 1 (2012).\\[0pt] [2] V.I. Mokeev \textit{et~al.} (CLAS Collaboration), Phys. Rev. \textbf{C86}, 035203 (2012).\\[0pt] [3] I.G. Aznauryan \textit{et~al.}, ``Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction,'' arXiv:1212.4891[nucl-th].
- Research Organization:
- Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1962061
- Report Number(s):
- JLAB-PHY-13-1871; DOE/OR/23177-5797
- Country of Publication:
- United States
- Language:
- English
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