XYZ-SU3 Breakings from Laplace Sum Rules at Higher Orders

Abstract

We present new compact integrated expressions of SU3 breaking corrections to QCD spectral functions of heavy-light molecules and four-quark XYZ-like states at lowest order (LO) of perturbative (PT) QCD and up to d=8 condensates of the OPE. Including N2LO PT corrections in the chiral limit and NLO SU3 PT corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results for the XYZ-like masses and decay constants from QCD spectral sum rules. Systematic errors are estimated from a geometric growth of the higher order PT corrections and from some partially known d=8 non-perturbative contributions. Our optimal results, based on stability criteria, are summarized in Tables 18 to 21 and compared with some LO results in Table 22. In most channels, the SU3 corrections on the meson masses are tiny: < 10% (resp. <3%) for the c (resp. b)-quark channel but can be large for the couplings (< 20%). Within the lowest dimension currents, most of the 0^{++} and 1^{++} states are below the physical thresholds while our predictions cannot discriminate a molecule from a four-quark state. A comparison with the masses of some experimental candidates indicates that the 0^{++} X(4500) might have a large D^*_{s0}D^*_{s0} molecule component while an interpretation of the 0^{++} candidates as four-quark ground states is not supported by our findings. The 1^{++} X(4147) and X(4273) are compatible with the D^*_{s}D_{s}, \bar D^*_{s0}D_{s1} molecules and/or with the axial-vector A_c four-quark ground state. Our results for the 0^{-\pm}, 1^{-\pm} and for different beauty states can be tested in the future data. Finally, we revisit our previous estimates [1] for the D^*_{0}D^*_{0} and D^*_{0}D_{1} and present new results for the D_1D_1.