The study of quasifree Compton scattering on the neutron in the energy range of Eγ=0.75–1.5 GeV is presented. The data reveal a narrow peak at W~1.685 GeV. This result, being considered in conjunction with the recent evidence for a narrow structure at W~1.68 GeV in η photoproduction on the neutron, suggests the existence of a nucleon resonance with unusual properties: a mass M~1.685GeV, a narrow width Γ⩽30 MeV, and the much stronger photoexcitation on the neutron than on the proton.
V. Kuznetsov, M. V. Polyakov, V. Bellini, T. Boiko, S. Chebotaryov, H.-S. Dho, G. Gervino, F. Ghio, A. Giusa, A. Kim, W. Kim, F. Mammoliti, E. Milman, A. Ni, I. A. Perevalova, C. Randieri, G. Russo, M. L. Sperduto, C. M. Sutera, A. N. Vall (2011)
Physical Review C – February 2011, Vol. 83, Issue 2, pp. 022201-1-022201-4, ISSN: 0556-2813, doi: 10.1103/PhysRevC.83.022201.
Physical Review C (PRC) contains research articles reporting experimental and theoretical results in all aspects of nuclear physics, including the nucleon-nucleon interaction, few-body systems, nuclear structure, nuclear reactions, relativistic nuclear collisions, hadronic physics and QCD, electroweak interaction, symmetries, and nuclear astrophysics.