Study of Quasi-two-body $B_{(s)}\to \phi (f_0(980)/f_2(1270)\to)\pi\pi$ Decays in Perturbative QCD Approach

TL;DR

This paper investigates quasi-two-body B meson decays involving phi and scalar or tensor mesons using perturbative QCD, providing theoretical predictions for branching fractions, CP asymmetries, and polarization fractions that align with experimental data.

Contribution

The study offers the first comprehensive perturbative QCD calculations of these specific B decay modes, including branching ratios and CP asymmetries, consistent with recent LHCb measurements.

Findings

Calculated branching fractions agree with LHCb data.

CP asymmetries are predicted to be very small.

Predictions for other decay channels are provided for future tests.

Abstract

In 2017, LHCb collaboration reported their first observation of the rare decays $B_s \to \phi (f_0(980)$ $/f_2(1270) \to ) \pi^+\pi^-$ and the evidence of $B^0 \to \phi(f_0(980)/f_2(1270)\to)\pi^+\pi^-$. Motivated by this, we study these quasi-two-body decays in the perturbative QCD approach. The branching fractions, $CP$ asymmetries and the polarization fractions are calculated. We find that within the appropriate two-meson wave functions, the calculated branching fractions are in agreement with the measurements of LHCb. Based on the narrow-width approximation, We also calculate the branching fractions of the quasi-two-body $B_{d,s}\to \phi(f_0(980)/f_2(1270)\to) \pi^0\pi^0$ and $B_{d,s}\to \phi(f_2(1270)\to) K^+K^-$, and hope the predictions to be tested in the ongoing LHCb and Belle II experiments. Moreover, the processes $B_{d,s}\to \phi f_2(1270)$ are also analyzed under this approximation. We note that the $CP$ asymmetries of these decays are very small, because these decays are either penguin dominant or pure penguin processes.