Precise theoretical prediction on branching fractions and polarizations of $D\to VV$ decays

Abstract

We present a precise and systematic analysis of $D\to VV$ decays within the factorization-assisted topological-amplitude approach, where $D$ denotes the set $\{D^0,D^{+},D_s^{+}\}$ and $V$ represents the vector mesons $\ddot{I},K^{\ast },\ddot{I}‰$, and $\ddot{I}•$. Given the limited current experimental data, the factorization-assisted topological-amplitude approach serves as a available phenomenological framework for predicting charmed meson decays to both vector mesons. In this framework, incorporating flavor SU(3) symmetry breaking effects, we can express nonfactorizable contributions of different modes as a minimal set of universal parameters globally fitted to experimental data. Utilizing 36 experimental data points for $D\to VV$ decays, we precisely extract ten nonfactorizable parameters associated with the $C$ and $E$ topological diagrams with $\ddot{I}{‡}^2/d.o.f.=8.43$. We find that a large strong phase in the longitude $E$ amplitude cause strong destructive interference with the $C$ longitudinal component, yielding $f_{\parallel }>f_L$, contrary to the naive factorization predictions. Additionally, for modes processing exclusively by the $E$ diagram, the amplitude hierarchy $|S|<|D|$ leads to a $D$-wave branching fraction larger than that of the $S$-wave. This explains recent observations that contradict $S$-wave dominance predictions. The predicted branching fractions and polarizations for 28 decay modes are consistent with existing experimental data. Unobserved modes, especially those with branching fractions of order $10^{-3}\sim 10^{-2}$, the $D$-wave dominated modes, and modes exhibiting $f_{\parallel }>f_L$, await measurement by BESIII, STCF, Belle II, and LHCb.

25 pages, 1 figures