Measurement of cross sections of p(e,e'pi^+)n for near pion threshold and high-lying resonances at high Q^2
During the last decade, remarkable experimental data have been collected in an extensive programs to study the excitation of nucleon resonance (N*) at Jefferson Laboratory through pion electroproduction using polarized electron beam and unpolarized proton target. The CEBAF Large Acceptance Spectrometer (CLAS) is well suited for the study of a broad range of kinematics in the invariant mass W and photon virtuality Q{sup 2} with nearly complete angular coverage for the hadronic decays. Electron scattering allows us to probe the effective degrees of freedom in excited nucleon states from meson-baryon to dressed quarks in terms of varying the distance scale. The study of nucleon structure allows us to understand these effective degrees of freedom. In this proceeding, I present preliminary cross sections for single pion production in mass range of high-lying resonances as well as near the pion threshold. Analysis of N{pi}{sup +} cross sections together with N{pi}{sup 0} and N {pi}{pi} exclusive electroproduction data, will allow us for the first time to determine electrocouplings of several high-lying excited proton states (W {ge} 1.6 GeV) at photon virtualities that correspond to the transition toward the dominance of quark degrees of freedom. I also present preliminary result on the E{sub 0+} multipole near pion threshold at 2.0 GeV{sup 2} {le} Q{sup 2} {le} 4.5 GeV{sup 2} using exclusive N{pi}{sup +} electroproduction data.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1038684
- Report Number(s):
- JLAB-PHY-11-1495; DOE/OR/23177-2062; TRN: US1201951
- Journal Information:
- AIP Conf. Proc., Vol. 1432; Conference: NSTAR 11, 17-20 May 2011, Newport News, VA
- Country of Publication:
- United States
- Language:
- English
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