engleski

First measurement of the K− n →Λ π− non-resonant transition amplitude below threshold

We present the analysis of K^− absorption processes on ^4He leading to Λπ^− final states, measured with the KLOE spectrometer at the DAPhiNE e+e− collider and extract, for the first time, the modulus of the non- resonant K^−n → Λπ^− direct production amplitude about 33 MeV below the KN threshold. This analysis also allows to disentangle the K^− nuclear absorption at-rest from the in-flight capture, for K^− momenta of about 120 MeV. The data are interpreted with the help of a phenomenological model, and the modulus of the non-resonant K^−n → Λπ^− amplitude for K^− absorption at-rest is found to be |A_(K^−n→ Λπ^−)| =(0.334 ± 0.018stat +0.034 −0.058 syst) fm.

Strong interaction ; Strangeness nuclear physics ; Antikaon interactions in nuclear matter

nije evidentirano