SYMMETRY-BREAKING CORRECTIONS TO MESON DECAY CONSTANTS IN THE HEAVY-QUARK EFFECTIVE THEORY

Spin- and flavor-symmetry-breaking corrections to decay constants of heavy mesons are analyzed in next-to-leading order in the 1/m(Q) expansion. The general structure of these corrections is derived in an effective-field-theory approach. The subleading universal form factors, which parametrize the matrix elements of higher-dimensional operators in the effective theory, axe estimated using QCD sum rules. The renormalization-group improvement of these low-energy parameters is discussed in detail. As an application, the spin-symmetry-violating effects responsible for the vector-pseudoscalar mass difference and for the ratio of the corresponding decay constants, f(V)/f(P), are calculated.