Exploring open-charm decay mode ${\Lambda }_c{\bar{\Lambda }}_c$ of charmonium-like state $Y(4630)$

Abstract

The newly observed $X,Y,Z$ exotic states are definitely not in the standard $Q{\bar{Q}}^{\prime }$ structures, thus their existence composes a challenge to our understanding on the fundamental principles of hadron physics. Therefore the studies on their decay patterns which are determined by the non-perturbative QCD will definitely shed light on the concerned physics. Generally the four-quark states might be in a molecular state or tetraquark or their mixture. In this work, we adopt the suggestion that $Y(4630)$ is a charmonium-like tetraquark made of a diquark and an anti-diquark. If it is true, its favorable decay mode should be $Y(4630)$ decaying into an open-charm baryon pair, since such a transition occurs via strong interaction and is super-OZI-allowed. In this work, we calculate the decay width of $Y(4630)\to {\Lambda }_c{\bar{\Lambda }}_c$ in the framework of the quark pair creation (QPC) model. Our numerical results on the partial width computed in the tetraquark configuration coincide with the Belle data within a certain error tolerance.

Comments: 8 pages, 4 figures, 1 table. Accepted by Eur. Phys. J. C