Two-roton bound state in helium II
Blagoveshchenskii M.M. , Dokukin E.B. , Kozlov Zh.A. , Parfenov V.A.
Results of an experiment in the neutron scattering in helium II at Τ = 1.2 К in the energy transfer region e~2 A are discussed. Experimental data indicate the presence in the excitation spectrum of He4 branch of a two-roton bound state.