Possibility of large lifetime differences in neutral B meson systems

Abstract

We investigate new physics models that can increase the lifetime differences in the B_q−B̅_q systems (q=d, s) above their standard model values. If both B_q as well as B̅_q can decay to a final state through flavor dependent new physics interactions, the so-called Grossman bound may be evaded. As examples, we consider the scalar leptoquark model and λ''-type R-parity violating supersymmetry. We find that models with a scalar leptoquark can enhance ΔΓ_s/Γ_s all the way up to its experimental upper bound and ΔΓ _d/Γ _d to as much as ~2.5%, at the same time allowing the CP violating phase β_s to vary between −45° and 20°. R-parity violating supersymmetry models cannot enhance the lifetime differences significantly, but can enhance the value of β_s up to ~±20°. This may bring the values of ΔΓ_q/Γ_q as well as β_s within the measurement capabilities of B factories and the B physics experiment at the Large Hadron Collider (LHCb). We also obtain bounds on combinations of these new physics couplings, and predict enhanced branching ratios of B_s/d→τ⁺τ ⁻.