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

Abstract

In the standard model the CP asymmetries in B → ψK S and B → ψK L are equal in magnitude and opposite in sign to very good approximation. We compute the order ǫ K corrections to each of these CP asymmetries and find that they give a deviation from sin 2β at the half percent level, which may eventually be measurable. However, the correction to a CP (B → ψK S )+a CP (B → ψK L ) due to ǫ K is further suppressed. The dominant corrections to this sum, at the few times 10 −3 level, come from the B lifetime difference, and CP violation in B − B mixing and B → ψK decay. New physics could induce a significant difference in the sin(∆m B t) time dependence in the asymmetries if and only if the "wrong-flavor" amplitudes B → ψK or B → ψK are generated. A scale of new physics that lies well below the weak scale would be required. Potential scenarios are therefore highly constrained, and do not appear feasible. A direct test is proposed to set bounds on such effects. * On leave of absence from the

Bound on the Ratio of Decay Amplitudes forB¯0→J/ψK*0andAubert1, Barate2, Boutigny3 et al. 2004Phys. Rev. Lett.

“…Together with theoretical information on the relation between the matrix elements for B 0 → J/ψ K 0 and B 0 → J/ψ K * 0 [3], the results presented here can be used to set a limit on the difference between A CP (J/ψ K 0 S ) and −A CP (J/ψ K 0 L ). We are grateful for the excellent luminosity and machine conditions provided by our PEP-II colleagues, and for the substantial dedicated effort from the computing organizations that support BABAR.…”

“…In this framework, the CP asymmetries in the proper-time distributions of neutral B decays to J/ψ K 0 S and J/ψ K 0 L are directly related to the CP -violation parameter sin2β [2]. The time-dependent CP asymmetries for J/ψ K 0 S and J/ψ K 0 L are of opposite sign and, to a very good approximation, equal in magnitude [3]. The decay…”

“…The so-called wrong-flavor B 0 decay amplitude to the opposite strangeness final state B 0 → J/ψ K 0 is expected to be negligible in the Standard Model [3]. Interference between a wrong-flavor amplitude and the favored amplitude can alter the relation between the CP asymmetries, A CP , for the J/ψ K 0 S and J/ψ K 0 L final states.…”

“…Interference between a wrong-flavor amplitude and the favored amplitude can alter the relation between the CP asymmetries, A CP , for the J/ψ K 0 S and J/ψ K 0 L final states. In general, a difference between A CP (J/ψ K 0 S ) and −A CP (J/ψ K 0 L ) of more than a few times 10 −3 requires a wrong-flavor amplitude [3]. A limit on the CPodd part of the phase difference between the wrong-flavor amplitude and the favored amplitude can be derived from the measured values of sin2β from B decays to the J/ψ K 0 S and J/ψ K 0 L final states.…”

“…The matrix elements, and therefore the ratio of wrong-flavor to favored amplitudes, are expected to be similar for B 0 → J/ψ K * 0 and B 0 → J/ψ K 0 [3]. In this Letter we present a measurement of the ratio of wrong-flavor to favored amplitude for the decay B 0 → J/ψ K * 0 , from the time-dependent asymmetry, where we use K * 0 → K + π − to identify the strangeness of the final state.…”