Examining coupled-channel effects in radiative charmonium transitions

Area of Science:

• * Particle Physics
• * Quantum Chromodynamics
• * Heavy Quarkonium Physics

Background:

• * Coupled-channel effects in charmonium transitions are of significant interest but not yet unambiguously established.
• * These effects involve the coupling of charmonia to charmed and anticharmed mesons.

Purpose of the Study:

• * To propose a clean and unambiguous method for examining coupled-channel effects in charmonium transitions.
• * To identify specific charmonium transitions suitable for experimental investigation.

Main Methods:

• * Analyzing hindered M1 radiative transitions from 2P to 1P charmonia.
• * Proposing specific decay ratios for experimental measurement: Γ(h(c)'→χ(cJ)γ)/Γ(χ(cJ)'→χ(cJ)π(0)) and Γ(χ(cJ)'→h(c)γ)/Γ(χ(cJ)'→χ(cJ)π(0)).

Main Results:

• * Hindered M1 radiative transitions from 2P to 1P charmonia are identified as suitable probes.
• * Parameter-free predictions are provided for the suggested decay ratios.

Conclusions:

• * The proposed method offers a clean way to establish coupled-channel effects in charmonium.
• * Experimental measurements of the suggested ratios can test these predictions and the underlying theoretical picture.
• * The findings can be further validated using lattice QCD calculations (both unquenched and quenched).