We estimate the decay width difference ΔΓd/Γd in the Bd system including 1/mb contributions and part of the next-to-leading order QCD corrections, and find it to be around 0.3%. We explicitly show that the time measurements of an untagged Bd decaying to a single final state isotropically can only be sensitive to quadratic terms in ΔΓd/Γd, and hence the use of at least two different final states is desired. We discuss such pairs of candidate decay channels for the final states and explore the feasibility of a ΔΓd/Γd measurement through them. The measurement of ΔΓd would be essential for an accurate measurement of sin(2β) at the LHC. The nonzero width difference can also be used to identify new physics effects and to resolve a twofold discrete ambiguity in the Bd-B̄d mixing phase. We also derive an upper bound on the value of ΔΓd/Γd in the presence of new physics, and point out some differences in the phenomenology of width differences in the Bs and Bd systems.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics