- Accepted Paper
Polarization fractions and helicity-dependent asymmetries in , and decays
Phys. Rev. D - Accepted 2 November, 2026
DOI: https://doi.org/10.1103/qt5g-qyrm
Phys. Rev. D - Accepted 2 November, 2026
DOI: https://doi.org/10.1103/qt5g-qyrm
In this paper, we present a phenomenological analysis of and decays using state-of-the-art perturbative QCD (pQCD) calculations. Our study is primarily motivated by recent polarization measurements from the LHCb and Belle II collaborations, which have significantly improved the precision of polarization fractions and enabled the first full determination of polarization-dependent CP asymmetries. This work extends the comprehensive pQCD study of charmless two-body decays reported in our previous paper [Chin. Phys. C 46 (2022) 123103], with a particular focus on polarization observables, especially the CP asymmetries in each helicity state, which reflect distinct orbital angular momentum configurations between the two vector mesons. Our predictions for the branching ratios and longitudinal polarization fractions in the and modes are in good agreement with the new experimental data. However, the calculated longitudinal polarization fraction for is significantly larger than the LHCb measurement. Moreover, the predicted (helicity-dependent) CP asymmetries in are about smaller than the observed values. These discrepancies point to a rich interplay between different topological amplitudes, highlighting the need for further theoretical investigation to resolve the long-standing polarization puzzle in two-body decays into vector mesons.
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