Diquark-antidiquark states with hidden or open charm and the nature of $X(3872)$

Diquark-antidiquark states with hidden or open charm and the nature of $X (3872)$

L. Maiani, F. Piccinini, A. D. Polosa, and V. Riquer

Phys. Rev. D 71, 014028 – Published 31 January 2005

Abstract

Heavy-light diquarks can be the building blocks of a rich spectrum of states which can accommodate some of the newly observed charmoniumlike resonances not fitting a pure $c \bar{c}$ assignment. We examine this possibility for hidden and open charm diquark-antidiquark states deducing spectra from constituent quark masses and spin-spin interactions. Taking the $X (3872)$ as input we predict the existence of a $2^{++}$ state that can be associated to the $X (3940)$ observed by Belle and reexamine the state claimed by SELEX, $X (2632)$ . The possible assignment of the previously discovered states $D_{s} (2317)$ and $D_{s} (2457)$ is discussed. We predict $X (3872)$ to be made of two components with a mass difference related to $m_{u} - m_{d}$ and discuss the production of $X (3872)$ and of its charged partner $X^{\pm}$ in the weak decays of $B^{+, 0}$ .