Charmless $B_{(s)}\to VV$ Decays in Factorization-Assisted Topological-Amplitude Approach

TL;DR

This paper analyzes 33 charmless B_(s) to VV decays using a factorization-assisted topological amplitude approach, extracting parameters from experimental data to predict decay properties and polarization fractions, with implications for ongoing experiments.

Contribution

It introduces a factorization-assisted topological amplitude method that decomposes decay amplitudes into universal parameters, improving predictions of decay observables over traditional approaches.

Findings

Large branching fractions and longitudinal polarization in tree-dominated decays.

Smaller branching fractions and polarization in color-suppressed decays.

Transverse polarization in penguin decays explained by a single transverse amplitude.

Abstract

Within the factorization-assisted topological-amplitude approach, we studied the 33 charmless $B_{(s)} \to VV$ decays, where $V$ stands for a light vector meson. According to the flavor flows, the amplitude of each process can be decomposed into 8 different topologies. In contrast to the conventional flavor diagrammatic approach, we further factorize each topological amplitude into decay constant, form factors and unknown universal parameters. By $\chi^2$ fitting 46 experimental observables, we extracted 10 theoretical parameters with $\chi^2$ per degree of freedom around 2. Using the fitted parameters, we calculated the branching fractions, polarization fractions, CP asymmetries and relative phases between polarization amplitudes of each decay mode. The decay channels dominated by tree diagram have large branching fractions and large longitudinal polarization fraction. The branching fractions and longitudinal polarization fractions of color-suppressed decays become smaller. Current experimental data of large transverse polarization fractions in the penguin dominant decay channels can be explained by only one transverse amplitude of penguin annihilation diagram. Our predictions of those not yet measured channels can be tested in the ongoing LHCb experiment and the Belle-II experiment in future.