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.
Bibliographical noteFunding Information:
We would like to thank G. Buchalla for many useful discussions and for a reading of the manuscript. We also thank U. Nierste for critical comments, and C. Shepherd-Thermistocleous, Y. Wah and H. Yamamoto for useful discussions concerning the experimental aspects. A.D. would like to thank the CERN Theory Division, where a large fraction of this work was completed. The work of C.S.K. was supported in part by CHEP-SRC Program, Grant No. 20015-111-02-2 and Grant No. R03-2001-00010 of the KOSEF, in part by BK21 Program and Grant No. 2001-042-D00022 of the KRF, and in part by Yonsei Research Fund, Project No. 2001-1-0057. The work of T.Y. was supported in part by the US Department of Energy under Grant No. DE-FG02-97ER-41036.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics