Contribution of the inelastic channels K − p → Yπ to the shift of the ground-state energy level of kaonic hydrogen

Abstract

The contribution of the inelastic channels K{sup -}p {sup {yields}} Y{pi}, where Y{pi} = {sigma}{sup -}{pi}{sup +}, {sigma}{sup +}{pi}{sup -}, {sigma}{sup 0}{pi}{sup 0}, or {lambda}{sup 0}{pi}{sup 0}, kinematically allowed at the K{sup -}p threshold to the S-wave scattering length of elastic K{sup -}p scattering, as well as the shift of the ground-state energy of kaonic hydrogen, is calculated. The result, {delta}a{sub 0}{sup K-p} = -0.037 {+-} 0.010 fm and {delta}{epsilon}{sub 1s} = 15 {+-} 4 eV, will be important for the theoretical analysis of the expected data from the experiments scheduled by the DEAR and SIDDHARTA Collaborations at the end of 2006.