Q2 Dependence of Quadrupole Strength in the gamma*p-->Delta+(1232) --> p pi0 Transition
Journal Article
·
· Physical Review Letters
OSTI ID:838763
Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q{sup 2} dependence of the magnetic (M{sub 1+}), electric (E{sub 1+}), and scalar (S{sub 1+}) multipoles in the {gamma}*p {yields} {Delta}{sup +}(1232) {yields} p{pi}{sup 0} transition. New precision measurements of the ratios E{sub 1+}/M{sub 1+} and S{sub 1+}/M{sub 1+} are reported here over the range Q{sup 2} = 0.4-1.8 GeV{sup 2}. Results are best described by recent unitary models in which the pion cloud plays a dominant role.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 838763
- Report Number(s):
- JLAB-PHY-01-89; DOE/ER/40150-4987; hep-ex/0110007; PRLTAO; TRN: US0501526
- Journal Information:
- Physical Review Letters, Vol. 88, Issue 3; Other Information: PBD: 6 Mar 2002; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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