Excited Heavy Mesons and Kaon Loops in Chiral Perturbation Theory

Abstract

We consider the effects of excited states on the $SU(3)$ breaking chiral loop corrections to heavy meson properties. In particular, we compare the size of kaon loops in which an excited heavy meson appears to the size of previously calculated loops with heavy mesons in the ground state. We find that the new effects may indeed be of the same magnitude as the old ones, but that there is a strong dependence on the unknown masses and coupling constants of the new states. As a result, we argue that the ground state loops alone may not be a trustworthy guide to $SU(3)$ corrections, and that the appropriate cutoff for a heavy-light chiral lagrangian which omits excited heavy mesons may be considerably smaller than the na\"ıve expectation of $Λ_χ\approx 1\gev$.