We use QCD sum rules to study the recently observed meson Z+ (4430), considered as a D* D1 molecule with JP = 0-. We consider the contributions of condensates up to dimension eight and work at leading order in αs. We get mZ = (4.40 ± 0.10) GeV in a very good agreement with the experimental value. We also make predictions for the analogous mesons Zs and Zb b considered as Ds* D1 and B* B1 molecules, respectively. For Zs we predict mZs = (4.70 ± 0.06) GeV, which is above the Ds* D1 threshold, indicating that it is probably a very broad state and, therefore, difficult to observe experimentally. For Zb b we predict mZb b = (10.74 ± 0.12) GeV, in agreement with quark model predictions.
|Number of pages||5|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2008 Mar|
Bibliographical noteFunding Information:
This work has been partly supported by FAPESP and CNPq-Brazil, and by the Korea Research Foundation KRF-2006-C00011.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics