Investigation of the conjectured nucleon deformation at low momentum transfer.
作者信息
Sparveris N F, Alarcon R, Bernstein A M, Bertozzi W, Botto T, Bourgeois P, Calarco J, Casagrande F, Distler M O, Dow K, Farkondeh M, Georgakopoulos S, Gilad S, Hicks R, Holtrop M, Hotta A, Jiang X, Karabarbounis A, Kirkpatrick J, Kowalski S, Milner R, Miskimen R, Nakagawa I, Papanicolas C N, Sarty A J, Sato Y, Sirca S, Shaw J, Six E, Stave S, Stiliaris E, Tamae T, Tsentalovich G, Tschalaer C, Turchinetz W, Zhou Z-L, Zwart T
机构信息
Institute of Accelerating Systems and Applications and Department of Physics, University of Athens, Athens, Greece.
出版信息
Phys Rev Lett. 2005 Jan 21;94(2):022003. doi: 10.1103/PhysRevLett.94.022003. Epub 2005 Jan 20.
We report new precise H(e,e(')p)pi(0) measurements at the Delta(1232) resonance at Q(2)=0.127 (GeV/c)(2) obtained at the MIT-Bates out-of-plane scattering facility which are particularly sensitive to the transverse electric amplitude (E2) of the gamma(*)N-->Delta transition. The new data have been analyzed together with those of earlier measurements to yield precise quadrupole to dipole amplitude ratios: Re(E(3/2)(1+)/M(3/2)(1+))=(-2.3+/-0.3(stat+syst)+/-0.6(model))% and Re(S(3/2)(1+)/M(3/2)(1+))=(-6.1+/-0.2(stat+syst)+/-0.5(model))% for M(3/2)(1+)=(41.4+/-0.3(stat+syst)+/-0.4(model))(10(-3)/m(pi(+))). The derived amplitudes give credence to the conjecture of deformation in hadrons favoring, at low Q2, the dominance of mesonic effects.
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