Study of Open-Charm Decays and Radiative Transitions of the X(3872)

Area of Science:

• Particle Physics
• Hadron Spectroscopy
• Quantum Chromodynamics

Background:

• The X(3872) is an exotic hadron whose internal structure remains debated.
• Understanding its decay modes provides crucial insights into its quark composition and formation mechanisms.

Purpose of the Study:

• To investigate the decay processes of the X(3872) particle.
• To measure branching ratios and set limits on specific decay channels, including X(3872)→D*0D0bar+c.c., γJ/ψ, γψ(2S), and γD+D-.

Main Methods:

• Analysis of a 9.0 fb⁻¹ data sample collected with the BESIII detector.
• Searched for specific decay signatures of the X(3872) at center-of-mass energies between 4.178 and 4.278 GeV.

Main Results:

• Observed the decay X(3872)→D*0D0bar+c.c. with a statistical significance of 7.4σ.
• Found evidence for X(3872)→γJ/ψ with a statistical significance of 3.5σ.
• Set an upper limit on the relative branching ratio R_{γψ} < 0.59 at 90% confidence level for X(3872)→γψ(2S).

Conclusions:

• The results confirm the presence of the X(3872)→D*0D0bar+c.c. decay and provide evidence for the X(3872)→γJ/ψ decay.
• The lack of significant signals for other channels and the established upper limit help constrain theoretical models of the X(3872) structure.