First Measurement of Polarizations in the Decay D^{0}→ωφ

Area of Science:

• Particle Physics
• High Energy Physics
• Quantum Chromodynamics

Background:

• Charm meson decays are crucial for testing the Standard Model.
• Understanding the dynamics of D0 decays provides insights into fundamental particle interactions.

Purpose of the Study:

• To report the first observation of the D0→ωϕ decay.
• To measure the branching fraction and analyze the polarization of the resulting ϕ and ω mesons.
• To compare experimental findings with theoretical predictions for charm meson decays.

Main Methods:

• Analysis of a data sample collected by the BESIII detector at a center-of-mass energy of 3.773 GeV.
• Measurement of the branching fraction for D0→ωϕ using 2.93 fb⁻¹ of integrated luminosity.
• Angular analysis to determine the polarization states of the ϕ and ω mesons.

Main Results:

• The D0→ωϕ decay was observed for the first time with a significance of 6.3σ.
• The branching fraction was measured as (6.48±0.96±0.40)×10⁻⁴.
• The ϕ and ω mesons were found to be transversely polarized.
• An upper limit on the longitudinal polarization fraction was set at <0.24 (95% confidence level).

Conclusions:

• The observed transverse polarization of ϕ and ω mesons in D0→ωϕ decay is inconsistent with theoretical expectations.
• These results challenge current understanding of the dynamics governing charm meson decays.
• Further theoretical and experimental investigations are needed to reconcile the findings.