Radial sensitivity of kaonic atoms and strongly boundK¯states

Abstract

The strength of the low-energy ${K}^{\ensuremath{-}}$-nucleus real potential has recently received renewed attention in view of experimental evidence for the possible existence of strongly bound ${K}^{\ensuremath{-}}$ states. Previous fits to kaonic atom data led to either ``shallow'' or ``deep'' potentials, where only the former are in agreement with chiral approaches but only the latter can produce strongly bound states. Here we explore the uncertainties of the ${K}^{\ensuremath{-}}$-nucleus optical potentials, obtained from fits to kaonic atom data, using the functional derivatives of the best-fit ${\ensuremath{\chi}}^{2}$ values with respect to the potential. We find that only the deep type of potential provides information that is applicable to the ${K}^{\ensuremath{-}}$ interaction in the nuclear interior.