First Measurement of Polarizations in the Decay D0 → ωφ

Using a data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at a center-of-mass energy root s = 3.773 GeV by the BESIII detector, the decay D-0 -> omega phi is observed for the first time. The branching fraction is measured to be (6.48 +/- 10.9 +/- 1 0.40) x 10(-4) with a significance of 6.3 sigma, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the phi and omega mesons from the D-0 -> omega phi decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

Automated summary

In this study, the decay D-0 -> ωφ is observed for the first time using the BESIII detector, with a measured branching fraction and significance. An angular analysis reveals that the φ and ω mesons from the decay are transversely polarized. Additionally, the upper limit of the longitudinal polarization fraction is found to be less than 0.24, which challenges current theoretical expectations and understanding of charm meson decays.