Width of exotics from QCD sum rules : tetraquarks or molecules?

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We investigate the widths of the recently observed charmonium like resonances X(3872), Z(4430) and Z_2(4250) using QCD sum rules.

• Extending previous analyses regarding these states as diquark-antiquark states or molecules of D mesons, we introduce the Breit-Wigner function in the pole term.
• We find that introducing the width increases the mass at small Borel window region.
• Using the OPE up to dimension eight, we find that the sum rules based on interpolating current with molecular components give a stable Borel curve from which both the masses and widths of these resonances can be well obtained.