Phenomenological studies on the $\bar{B}^0\rightarrow [K^-\pi^+]_{S/V}[\pi^+\pi^-]_{V/S} \rightarrow K^-\pi^+\pi^+\pi^-$ decay

TL;DR

This paper investigates the CP violation and branching ratios in a specific four-body B meson decay using a quasi-two-body decay model, considering various resonances and their dynamical functions, providing theoretical predictions for CP asymmetries and decay rates.

Contribution

It introduces a detailed phenomenological analysis of the four-body decay $ar{B}^0 ightarrow K^- extpi^+ extpi^+ extpi^-$ incorporating multiple resonances and models, offering new predictions within the QCD factorization framework.

Findings

Predicted CP asymmetry range: [-0.383, 0.421]

Branching fraction range: [7.36, 199.69] x 10^{-8}

Calculated CP asymmetries and branching ratios for two-body and four-body decays.

Abstract

Within the quasi-two-body decay model, we study the localized $CP$ violation and branching fraction of the four-body decay $\bar{B}^0\rightarrow [K^-\pi^+]_{S/V}[\pi^+\pi^-]_{V/S} \rightarrow K^-\pi^+\pi^-\pi^+$ when $K^-\pi^+$ and $\pi^-\pi^+$ pair invariant masses are $0.35<m_{K^-\pi^+}<2.04 \, \mathrm{GeV}$ and $0<m_{\pi^-\pi^+}<1.06\, \mathrm{GeV}$, with the pairs being dominated by the $\bar{K}^*_0(700)^0$, $\bar{K}^*(892)^0$, $\bar{K}^*(1410)^0$, $\bar{K}^*_0(1430)$ and $\bar{K}^*(1680)^0$, and $f_0(500)$, $\rho^0(770)$ , $\omega(782)$ and $f_0(980)$ resonances, respectively. When dealing with the dynamical functions of these resonances, $f_0(500)$, $\rho^0(770)$, $f_0(980)$ and $\bar{K}^*_0(1430)$ are modeled with the Bugg model, Gounaris-Sakurai function, Flatt$\acute{\mathrm{e}}$ formalism and LASS lineshape, respectively, while others are described by the relativistic Breit-Wigner function. Adopting the end point divergence parameters $\rho_A\in[0,0.5]$ and $\phi_A\in[0,2\pi]$, our predicted results are $\mathcal{A_{CP}}(\bar{B}^0\rightarrow K^-\pi^+\pi^+\pi^-)\in[-0.383,0.421]$ and $\mathcal{B}(\bar{B}^0\rightarrow K^-\pi^+\pi^+\pi^-)\in[7.36,199.69]\times10^{-8}$ based on the hypothetical $q\bar{q}$ structures for the scalar mesons in the QCD factorization approach. Meanwhile, we calculate the $CP$ violating asymmetries and branching fractions of the two-body decays $\bar{B}^0\rightarrow SV(VS)$ and all the individual four-body decays $\bar{B}^0\rightarrow SV(VS) \rightarrow K^-\pi^+\pi^-\pi^+$, respectively. Our theoretical results for the two-body decays $\bar{B}^0\rightarrow \bar{K}^*(892)^0$$f_0(980)$, $\bar{B}^0\rightarrow \bar{K}^*_0(1430)^0$$\omega(782)$, $\bar{B}^0\rightarrow \bar{K}^*(892)^0f_0(980)$, $\bar{B}^0\rightarrow\bar{K}^*_0(1430)^0\rho$,