SU(3) mass-splittings of heavy-baryons in QCD

We extract directly (for the first time) the charmed (C=1) and bottom (B=−1) heavy-baryons (spin 1/2 and 3/2) mass-splittings due to SU(3) breaking using double ratios of QCD spectral sum rules (QSSR) in full QCD, which are less sensitive to the exact value and definition of the heavy quark mass, to the perturbative radiative corrections and to the QCD continuum contributions than the simple ratios commonly used for determining the heavy baryon masses. Noticing that most of the mass-splittings are mainly controlled by the ratio κ≡〈s¯s〉/〈d¯d〉 of the condensate, we extract this ratio, by allowing 1σ deviation from the observed masses of the Ξc,b and of the Ωc. We obtain: κ=0.74(3), which improves the existing estimates: κ=0.70(10) from light hadrons. Using this value, we deduce MΩb=6078.5(27.4) MeV which agrees with the recent CDF data but disagrees by 2.4σ with the one from D0. Predictions of the ΞQ′ and of the spectra of spin 3/2 baryons containing one or two strange quark are given in Table 2. Predictions of the hyperfine splittings ΩQ∗−ΩQ and ΞQ∗−ΞQ are also given in Table 3. Starting for a general choice of the interpolating currents for the spin 1/2 baryons, our analysis favours the optimal value of the mixing angle b≃(−1/5-0) found from light and non-strange heavy baryons.