Revisiting the Annihilation Corrections in Non-leptonic $\bar{B}_s^0$ Decays within QCD Factorization

TL;DR

This paper revisits annihilation corrections in $ar{B}_s^0$ decays within QCD factorization, comparing parameterization and infrared gluon propagator schemes, and highlights discrepancies between theoretical predictions and recent experimental data.

Contribution

It introduces two schemes for handling end-point divergences in $ar{B}_s^0$ decays and analyzes their implications for decay rate predictions, addressing existing experimental-theoretical discrepancies.

Findings

Most predictions agree with data using an infrared finite gluon propagator.

Predicted $ar{B}_s^0 o ext{phi phi}$ decay rates are larger than $ar{B}_s^0 o K^{*0}ar{K}^{*0}$, contrary to experimental results.

The pattern $ ext{BR}(ar{B}_s^0 o ext{phi phi}) > ext{BR}(ar{B}_s^0 o K^{*0}ar{K}^{*0})$ persists across theoretical frameworks.

Abstract

Motivated by the recent measurements of non-leptonic $\bar{B}_s^0$ decays by CDF and LHCb collaborations, especially the large ${\cal B}(\bar{B}_s^0\to\pi^+\pi^-)$, we revisit the hard spectator and annihilation corrections in $\bar{B}_s^0$ decays within QCD factorization approach with two schemes for the possible parameters for the known end-point divergence appeared in the estimation of the hard spectator and annihilation diagrams. The first one is to conservatively estimate the possible contributions by parameterization (scheme I); another one uses an infrared finite gluon propagator (scheme II) to regulate the end-point singularity. In scheme I, with the constraints from the measured $\bar{B}_s^0\to PP (VV)$ decays, two (four) restricted solutions of the parameters spaces are found. In scheme II, we find that most of the theoretical predictions agree well with the experimental data with single parameter $m_{g}\sim 0.5{\rm GeV}$. However, within both schemes, ${\cal B}(\bar{B}_s^0\to\phi\phi)$ are always much larger than ${\cal B}(\bar{B}_s^0\to K^{\ast 0}\bar{K}^{\ast 0})$ in contrast to the experimental results ${\cal B}(\bar{B}_s^0\to\phi\phi)\simeq{\cal B}(\bar{B}_s^0\to K^{\ast 0}\bar{K}^{\ast 0})$. It is noted that the pattern ${\cal B}(\bar{B}_s^0\to\phi\phi)>{\cal B}(\bar{B}_s^0\to K^{\ast 0}\bar{K}^{\ast 0})$ also persists in other theoretical framework, thus the present experimental result ${\cal B}(\bar{B}_s^0\to\phi\phi) \simeq {\cal B}(\bar{B}_s^0\to K^{\ast 0}\bar{K}^{\ast 0})$ rises a challenge to theoretical approaches for B non-leptonic decays. Further refined measurements and theoretical studies are called for to resolve such a possible anomaly.