and molecules at N2LO from QSSR

We use QCD spectral sum rules (QSSR) and the factorization properties of molecule currents to estimate the masses and couplings of the and molecules at N2LO of PT QCD. We include in the OPE the contributions of non-perturbative condensates up to dimension-eight. With the Laplace sum rules approach (LSR) and in the -scheme, we obtain MD⁎D=3738(152)MeV, which agrees within the errors with the newly discovered Zc(3900). For the bottom channel, we find MB⁎B=10687(232)MeV in good agreement with the observed Zb(10610). Couplings of these states to the currents are also extracted. Our results are improvements of the LO ones in the existing literature.