Heavy meson hyperfine splitting: A Complete 1/m(Q) calculation

Abstract The hyperfine splittings Δ d = (m d s ∗ − m nd s ) − (m d ∗+ − m d + ) and Δ d = (m b s ∗ − m b s ) − (m b ∗0 − m b 0 ) are analyzed in the framework of an effective lagrangian possessing chiral, heavy flavour and spin symmetries, explicitly broken by a complete set of first order terms. Among these terms, those responsible for the difference between the couplings gp ∗ p ∗ π and gp ∗ p π are evaluated in the QCD sum rules approach. Their contribution to Δ d and to Δ b appears to quantitatively balance previously estimated chiral effects, in nice agreement with the experimental data, solving a suspected puzzle for heavy quark theory.