Anomalies in Hadronic B Decays

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• Flavor SU(3) symmetry is a theoretical framework used to analyze decays of B mesons into pairs of pseudoscalar mesons (B→PP).
• Individual fits to decays with ΔS=0 or ΔS=1 are generally good, suggesting the symmetry holds in certain contexts.

Purpose of the Study:

• To test the validity of flavor SU(3) symmetry in combined fits of B→PP decays.
• To quantify the discrepancy between experimental data and theoretical predictions within the Standard Model assuming SU(3)_{F}.

Main Methods:

• Performing combined fits to B→PP decays (B={B^{0},B^{+},B_{s}^{0}}, P={π,K}) under the assumption of flavor SU(3) symmetry.
• Analyzing the impact of SU(3)_{F}-breaking effects and QCD factorization on the fits.

Main Results:

• A poor combined fit to B→PP decays was observed, revealing a 3.6σ disagreement with the Standard Model assuming SU(3)_{F} (SM_{SU(3)_{F}}).
• Resolving this discrepancy requires substantial SU(3)_{F}-breaking effects (around 1000%).
• Incorporating QCD factorization assumptions further increased the discrepancy to 4.4σ.

Conclusions:

• The assumption of flavor SU(3) symmetry is significantly challenged by the combined analysis of B→PP decays.
• Large SU(3)_{F}-breaking effects are necessary to reconcile theoretical predictions with experimental observations.
• The results highlight potential limitations of current theoretical models in describing these particle decays.