Strangeness modes in nuclei tested by antineutrinos

Abstract

Production of negative strangeness in reactions of inelastic anti-neutrino scattering on a nucleus provides information on the modification of strange degrees of freedom in nuclear matter. We calculate cross-sections of the reaction channelsν e(µ) → e + (µ + ) + K − andν e(µ) + p → Λ + e + (µ + ) and investigate their sensitivity to the medium effects. In particular, we consider effects induced by the presence of a low-energy excitation mode in the K − spectrum, associated with the correlated Λ-particle and proton-hole states, and the renormalization of the weak interaction in medium. In order to avoid double counting, various contributions to anti-neutrino scattering are classified with the help of the optical theorem, formulated within the non-equilibrium Green's function technique.

Negative kaons in dense baryonic matter

“…Here, we find contributions to the K − polarization operator from the hyperon poles in the K − N scattering amplitude determined by (15,16,17). Relying on explicit calculations of Refs [6,15] we can easily incorporate scalar and vector mean-fields acting on baryons.…”

“…In principle, this information could be extracted from the data on multi-strange hyper-nuclei, which, however, are rather poor, if not absent. In the work [15] the Landau-Migdal parameter f ′ Λ was estimated in line with Refs. [57], where Landau-Migdal parameters of the nucleon-nucleon interaction were calculated within Ericson-Ericson-Lorentz-Lorenz approach.…”

“…Relying on explicit calculations of Refs [6,15] we can easily incorporate scalar and vector mean-fields acting on baryons. The scalar field is taken into account with the help of the replacement m B → m * B and the baryon vector potentials are included in the pole terms by the shift of the kaon frequency ω → ω + δv iH , with δv iH = V i − V H , i = {n, p}, H = {Λ, Σ} , that immediately follows from the difference of the baryon energies, see (3).…”

“…Compared to [15] we obtained a smaller value of the corresponding parameter C 0 f ′ Λ ≃ 0.6/m 2 π , since we included here the form-factors mentioned above [77].…”

“…The momentum dependence of kaon yields is experimentally measured [18]. Also, the multi-branch K − spectrum can be tested viaν-scattering on atomic nuclei [15]. Peculiarities of the K − -nucleon interaction near mass shell are of great importance for the physics of K − atoms [19,20].…”