Searches for B^{0}→K^{+}π^{-}τ^{+}τ^{-} and B_{s}^{0}→K^{+}K^{-}τ^{+}τ^{-} Decays

Area of Science:

• Particle Physics
• High Energy Physics
• Standard Model

Background:

• Searches for rare B meson decays provide crucial tests of the Standard Model.
• Investigating decays involving tau leptons can reveal new physics phenomena.
• Previous searches for B0→K^{+}π^{-}τ^{+}τ^{-} and B_{s}^{0}→K^{+}K^{-}τ^{+}τ^{-} were limited in scope.

Purpose of the Study:

• To conduct the first searches for B0→K^{+}π^{-}τ^{+}τ^{-} and B_{s}^{0}→K^{+}K^{-}τ^{+}τ^{-} decays.
• To set upper limits on the branching fractions of these rare decays.
• To establish new limits for B0→K^{*}(892)^{0}τ^{+}τ^{-} and B_{s}^{0}→ϕ(1020)τ^{+}τ^{-} decays.

Main Methods:

• Analysis of proton-proton collision data from the LHCb experiment.
• Reconstruction of tau leptons via the τ^{+}→μ^{+}ν[over ¯]_{τ}ν_{μ} decay channel.
• Setting upper limits on branching fractions in bins of K^{+}π^{-} or K^{+}K^{-} mass.

Main Results:

• No significant signal was observed for the searched decays.
• The first upper limits were set for B0→K^{+}π^{-}τ^{+}τ^{-} outside the K^{*}(892)^{0} region and for B_{s}^{0}→K^{+}K^{-}τ^{+}τ^{-}.
• Upper limits were established for B0→K^{*}(892)^{0}τ^{+}τ^{-} (2.8×10^{-4} at 95% CL) and B_{s}^{0}→ϕ(1020)τ^{+}τ^{-} (4.7×10^{-4} at 95% CL).

Conclusions:

• The study provides stringent new constraints on the branching fractions of the investigated B meson decays.
• The improved upper limit for B0→K^{*}(892)^{0}τ^{+}τ^{-} is an order of magnitude stronger than previous results.
• These results contribute to the ongoing search for New Physics beyond the Standard Model.