Eur. Phys. J. C (2009) 59: 675-681
https://doi.org/10.1140/epjc/s10052-008-0812-2

Regular Article - Theoretical Physics

Possible tetraquark states in the π ⁺ χ _c1 invariant-mass distribution

¹ Department of Physics, North China Electric Power University, Baoding, 071003, China
² Kavli Institute for Theoretical Physics China, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100080, China

^* e-mail: wangzgyiti@yahoo.com.cn

Received: 7 August 2008
Revised: 5 November 2008
Published online: 28 November 2008

Abstract

In this article, we assume that there exist hidden charmed tetraquark states with spin–parity J ^P=1⁻, and we calculate their masses with the QCD sum rules. The numerical result indicates that the masses of the vector hidden charmed tetraquark states are about M _Z =(5.12±0.15) GeV or M _Z =(5.16±0.16) GeV, which are inconsistent with the experimental data on the π ⁺ χ _c1 invariant-mass distribution. The hidden charmed mesons Z ₁, Z ₂ or Z may be scalar hidden charmed tetraquark states, hadro-charmonium resonances or molecular states.