Kaonic helium atoms in relation to kaonic nuclear bound states

A long-standing problem of K-4He atom, an abnormal 2p level shift due to strong interaction, is investigated from coupled-channel point of view. An anomalous upward shift of ΔEcc2p = -11 eV and Γcc2p = 21 eV is obtained. The concept of 'proximity shift' is introduced, and the effect of centrifugal repulsion in the decay channel is discussed. The atomic 2p-level shift measurement will provide a crucial information concerning p-wave kaonic nuclear bound state, which reinforces the picture that the So(3115) and S+(3140) tribaryons are dense K nuclei. (author)