NewCP-violating parameters in cascade decays

Abstract

We consider decay chains of the type P→M ϩ•••→ f ϩ•••, where M is a neutral meson that may mix with its antiparticle M , before decaying into the final state f. Here P may be either a heavier neutral meson or a charged meson. We perform a rephasing-invariant analysis of the quantities that show up in such cascade decays. If the decay P→M ϩ••• ͑or the decay P→M ϩ•••) is forbidden, we find the usual f parameters describing the interference between the mixing of a neutral meson system and the decay from that system into the final state f. However, when both the P→M ϩ••• and P→M ϩ••• decays are allowed, we find a new class of rephasing-invariant parameters, i , which measure the interference between the mixing of a neutral meson system and the decay from the initial state into that system. We show that the quantities f and i are necessary and sufficient to describe all the interference effects present in the most general cascade decay. We discuss the various cascade decays in turn, highlighting the special features of each one.

Can the CP asymmetries in B→ψKS and B→ψKL differ?

“…To study the effect of kaon mixing, it is most convenient to use the cascade mixing formalism [3,9,10,11,12]. In particular, to obtain the total B → ψK → ψππ amplitude a coherent sum is performed over the physical B and K mass eigenstate contributions,…”

Impact ofD0−D0¯mixing on the experimental determi

“…Otherwise, new physics effects in the D 0 − D 0 system could be misidentified as new physics in the B d system. In fact, Meca and Silva [7] have used x D ∼ 10 −2 to argue that these effects could be of order 10% in B ± → f D K ± decays, and they may be as large as 100% in [8]. The main objective of our article is to study in detail the effect of D 0 − D 0 mixing on the measurement of γ in B ± → DX ± decays.…”

“…We should stress that the D 0 − D 0 mixing effects might be of order unity, or even dominate, in the B ± → Dπ ± and B ± → Dρ ± decays, becauseǫ π ∼ 0.004 [8]. As a result, even SM values around x D ∼ y D ∼ 10 −3 , would lead to a 10% effect in these channels [8].…”

“…As a result, even SM values around x D ∼ y D ∼ 10 −3 , would lead to a 10% effect in these channels [8].…”

Quantum coherent measurements

“…Studies of the effects of both D mixing [36,37,38,39,40,41] and D CP violation [42,43,44,45] seem to be essentially complete now. In general, one can include effects where relevant in the γ analyses.…”