Analysis of the B --> \pi \ell^+ \ell^- Decay in the Standard Model with Fourth Generation

TL;DR

This paper explores how a hypothetical fourth quark generation could affect B meson decay properties, providing potential indirect evidence for new physics beyond the Standard Model.

Contribution

It analyzes the impact of fourth-generation quarks on B --> pi l+ l- decay observables, highlighting their dependency on new quark masses and mixing parameters.

Findings

Branching ratios are strongly affected by fourth-generation parameters.

CP asymmetry and lepton polarization depend on the fourth-generation quark mass.

Results can help search for fourth-generation quarks through loop effects.

Abstract

We investigate the influence of the fourth generation quarks on the branching ratio and the CP-asymmetry in B -->\pi \ell^+ \ell^- decay. Taking the |V_{t'd}V_{t'b}| ~ 0.001 with phase about 10 degree, which is consistent with the sin2\phi_1 of the CKM and the B_d mixing parameter \Delta m_{B_d}, we obtain that for both muon and tau channels the branching ratio, the magnitude of CP-asymmetry and lepton polarization depict strong dependency on the 4th generation quarks mass and mixing parameters. These results can serve as a good tool to search for new physics effects, precisely, to search for the fourth generation quarks($t', b')$ via its indirect manifestations in loop diagrams.