Are there any narrow $K^-$- nuclear states?
We performed self-consistent calculations of $K^-$-nuclear quasi-bound states using a single-nucleon $K^-$ optical potential derived from chiral meson-baryon coupled-channel interaction models, supplemented by a phenomenological $K^-$ multinucleon potential introduced recently to achieve good fits to kaonic atom data [1]. Our calculations show that the effect of $K^-$ multinucleon interactions on $K^-$ widths in nuclei is decisive. The resulting widths are considerably larger than corresponding binding energies. Moreover, when the density dependence of the $K^-$-multinucleon interactions derived in the fits of kaonic atoms is extended to the nuclear interior, the only two models acceptable after imposing as additional constraint the single-nucleon fraction of $K^-$ absorption at rest do not yield any kaonic nuclear bound state in majority of considered nuclei.