Nucleon resonance electrocouplings in the non-perturbative regime
There is an extensive search for baryon resonances using the CLAS detector in Hall B of JLab. Extracting the transition helicity amplitudes (or the {gamma}{sub v}NN* photo- and electrocouplings) sheds light on nature of the non-perturbative strong interaction. We have extended the data on differential cross sections to Q{sup 2} = 6.0 GeV{sup 2} for the {pi}N electroproduction channel. Electroproduction data were also collected on the two-charged-pion channel off protons, which provides nine independent differential {pi}{sup +}{pi}{sup -}p cross sections at Q{sup 2} up to 1.5 GeV{sup 2}. The two-pion results, moreover, are consistent with those from independent {pi}N electroproduction analyses, where the background contributions in the two-pion channel are completely different from that of the single-pion one. A phenomenological approach developed at Jefferson Lab - Moscow State University is employed for separating the resonant and non-resonant contributions to the final state. The Q{sup 2}-dependent electrocouplings were then obtained for the P{sub 11}(1440) and D{sub 13}(1520) excited baryon states. The new data will be discussed in light of these new developments in systematically exploring the affects of meson-baryon dressing on the transition helicity amplitudes as a function of Q{sup 2}.
- 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:
- 1049373
- Report Number(s):
- JLAB-PHY-12-1616; DOE/OR/23177-2304; NSF Grant PHY-0855661; TRN: US1204809
- Journal Information:
- Proceedings of Science, Vol. QNP2012; Conference: QNP 2012, April 16-20, 2012, Palaiseau, France
- Country of Publication:
- United States
- Language:
- English
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