Newly observed X(4630): a new charmoniumlike molecule

Abstract

Very recently, the LHCb Collaboration at the Large Hadron Collider at CERN observed new resonance X(4630). The X(4630) is decoded as a charmoniumlike molecule with hidden-strange quantum number well in the one-boson-exchange mechanism. Especially, the study of its hidden-charmed decays explicitly shows the dominant role of $$J/\psi \phi $$ J / ψ ϕ among all allowed hidden-charmed decays of the X(4630), which enforces the conclusion of X(4630) as a charmoniumlike molecule. The discovery of the X(4630) is a crucial step of constructing charmoniumlike molecule zoo.

Light- and heavy-quark symmetries and the $Y(4230)$, $Y(4360)$, $Y(4500)$, $Y(4620)$ and $X(4630)$ resonances

“…This discovery connects with previous predictions of D * s D * s2 virtual states with a similar mass [26], but it has also been explained as a bound state [27] and there are non-molecular explanations too [28,29].…”

“…This might potentially change our conclusions and indicate that the most promising molecular interpretation of the X(4630) is a 1 −+ D * s Ds1 bound state, which will be in agreement with Ref. [27]. Conversely, if scenario B is correct, this will further cement the conclusion that the X(4630) is better reproduced as a 2 −+ D * s D s1 bound state.…”

“…This means that it is more likely than not that we are underpredicting the amount of attraction of a few configurations of the D * D1 and D * s Ds1 systems. Of particular importance here is the sign of the spin-spin coupling: an attractive spin-spin term will reinforce the conclusion that the X(4630) is a 2 −+ D * s Ds1 molecule, while a repulsive one will favor binding in the 1 −+ D * s Ds1 configuration, which will thus become the preferred interpretation of the X(4630) (as happens in [27,29]). The eventual experimental observation of molecular candidates in these systems together with improved lattice calculations (in the line of Refs.…”

Resonance $X(4630)$

“…These experimental results generated a theoretical activity aimed to explain obtained information in the context of various approaches of high energy physics. Studies were concentrated mainly around the resonances X(4630) and Z cs , in which authors calculated masses, magnetic moments of these states, explored their decay channels [4][5][6][7][8]. Some of new states were explained as threshold effects as well [9].…”

“…Thus, it was considered in Ref. [6] as the molecule D * s D s1 (2536) with required spin-parities. An analysis was performed there using the one-boson-exchange method.…”