Status of the N * program at Jefferson Lab
Recent results in electromagnetic excitation of nucleon resonance are presented, and confronted with theoretical predictions. Preliminary data in the search for missing states are discussed as well. Resonance electroproduction has rich applications in nucleon structure studies at intermediate and large distances. Resonances play an important role in understanding the spin structure of the nucleon. More than 80% of the helicity-dependent integrated total photoabsorption cross-section difference (GDH integral) is a result of the excitation of the {Delta}(1232). At Q{sup 2} = 1 GeV{sup 2}, about 40% of the first moment {Lambda}{sub 1}{sup P}(Q{sup 2}) = {integral}{sub 0}{sup 1} g{sub 1}(x, Q{sup 2})dx for the proton is due to contributions of the resonance region at W < 2 GeV. Conclusions regarding the nucleon spin structure for Q{sup 2} < 2 GeV{sup 2} must therefore be regarded with some scepticism if contributions of baryon resonances are not taken into account.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 1040775
- Report Number(s):
- JLAB-PHY-02-195; DOE/ER/40150-4961; TRN: US1202553
- Journal Information:
- The European Physical Journal, A, Vol. 17, Issue 3; ISSN 1434-6001
- Country of Publication:
- United States
- Language:
- English
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