D*D and B*B (1⁺⁺) molecules at N2LO from QSSR

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We use QCD spectral sum rules (QSSR) and the factorization properties of molecule currents to estimate the masses and couplings of the D*D and B*B (1⁺⁺) 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 MS-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.