Search for $\chi_{c_J}(2P)$ from Higher Charmonim E1 Transitions and X,Y,Z States

TL;DR

This paper calculates E1 transition widths of higher vector charmonium states to 2P states, aiming to identify these states and clarify the nature of X,Y,Z states, with implications for experimental detection at electron-positron colliders.

Contribution

It provides theoretical predictions for E1 transition widths and branching ratios of higher charmonium states, exploring their potential to identify and distinguish X,Y,Z states.

Findings

Calculated branching ratios for $ o o o$ transitions are in the range of $10^{-4}-10^{-3}$.

Transition widths are sensitive to 3S-2D mixing angles of $ o$ states.

Experimental measurements can constrain mixing angles and identify charmonium states.

Abstract

We calculate the E1 transition widths of higher vector charmonium states into the spin-triplet 2P states in three typical potential models, and discuss the possibility to detect these 2P states via these E1 transitions. We attempt to clarify the nature of some recently observed X,Y,Z states by comparing them with these 2P charmonium states in these E1 transitions. In particular, the calculated branching ratios of $\psi(4040),\psi(4160)\to \chi^{'}_{c_J}\gamma$ (J=0,1,2) are found to be in the range of $10^{-4}-10^{-3}$, and sensitive to the 3S-2D mixing of $\psi(4040)$ and $\psi(4160)$. The mixing angle may be constrained by measuring $\psi(4040),\psi(4160)\to Z(3930)\gamma$, if Z(3930) is identified with the $\chi^{'}_{c_2}$ state, and then be used in measuring $\chi^{'}_{c_{0,1}}$ states. These processes can be studied experimentally at $e^+e^-$ colliders such as BEPCII/BESIII and CESR/CLEO.