Estimating the mass of the hidden charm tetraquark state via QCD sum rules

Cong- Feng Qiao; Liang Tang

doi:10.1140/epjc/s10052-014-3122-x

EPJ

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2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2014) 74: 3122
https://doi.org/10.1140/epjc/s10052-014-3122-x

Regular Article - Theoretical Physics

Estimating the mass of the hidden charm $1^+(1^{+})$ tetraquark state via QCD sum rules

Cong- Feng Qiao and Liang Tang^*

Department of Physics, University of Chinese Academy of Sciences, YuQuan Road 19A, Beijing, 100049, China

^* e-mail: tangl@ucas.ac.cn

Received: 4 July 2014
Accepted: 7 October 2014
Published online: 29 October 2014

Abstract

By using QCD sum rules, the mass of the hidden charm tetraquark $[cu][\bar{c}\bar{d}]$ state with $I^{G} (J^{P}) = 1^+ (1^{+})$ (HCTV) is estimated, which presumably will turn out to be the newly observed charmonium-like resonance $$Z_c^+(3900)$$ . In the calculation, contributions up to dimension eight in the operator product expansion (OPE) are taken into account. We find $m_{1^+}^c = (3912^{+306}_{-153}) \, \text {MeV}$ , which is consistent, within the errors, with the experimental observation of . Extending to the b-quark sector, $m_{1^+}^b = (10561^{+395{}^{}}_{-163}) \,\text {MeV}$ is obtained. The calculational result strongly supports the tetraquark picture for the “exotic” states of $$Z_c^+(3900)$$ and $$Z_b^+(10610)$$ .