Measurement of the lifetime difference of Bd mesons: possible and worthwhile?

Abstract

We estimate the decay width difference ∆Γ d /Γ d in the B d system including 1/m b 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 B d decaying to a single final state isotropically can only be sensitive to quadratic terms in ∆Γ d /Γ d , 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 ∆Γ d /Γ d measurement through them. The measurement of ∆Γ d 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 B d -B d mixing phase. We also derive an upper bound on the value of ∆Γ d /Γ d in the presence of new physics, and point out some differences in the phenomenology of width differences in the B s and B d systems.

Fluctuating annihilation cross sections and the generation of density perturbations

“…4 was calculated in [24] and Γ (1) 3 was calculated in [21] and [10]. • Lattice determination of dimension 7 operators for Γ 4…”

CP violation in the Bs0 system

“…1/m b corrections for the sub-leading CKM structures in Γ s 12 (Dighe et al, 2002) and 1/m 2 b corrections for ∆Γ s (Badin et al, 2007) were also determined; their numerical effect is small. A commonly used Standard Model prediction for ∆Γ s was given by ∆Γ SM,2011…”

Lifetime differences in heavy mesons with time independent measurements

“…As was shown in Eqns. (4,5), the states of interest can be decomposed into the coherent sum of products of flavor (or CP) eigenstates. Using Eqn.…”

“…In the case of B 0 d , x = 0.730 ± 0.029 [3] and y is small, of the order of 0.3% [4]. It is possible that at future B-factories there would be enough statistics to measure y.…”