A roadmap to control penguin effects in B d 0  → J/ψK S 0 and B s 0  → J/ψϕ

Abstract

The theoretical interpretation of the corresponding observables is limited by uncertainties from doubly Cabibbo-suppressed penguin topologies. With continuously increasing experimental precision, it is mandatory to get a handle on these contributions, which cannot be calculated reliably in QCD. In the case of the measurement of sin 2β from B 0 d → J/ψK 0 S , the U -spinrelated decay B 0 s → J/ψK 0 S offers a tool to control the penguin effects. As the required measurements are not yet available, we use data for decays with similar dynamics and the SU(3) flavour symmetry to constrain the size of the expected penguin corrections. We predict the CP asymmetries of B 0 s → J/ψK 0 S and present a scenario to fully exploit the physics potential of this decay, emphasising also the determination of hadronic parameters and their comparison with theory. In the case of the benchmark mode B 0 s → J/ψφ used to determine the B 0 s -B 0 s mixing phase φ s the penguin effects can be controlled through B 0 d → J/ψρ 0 and B 0 s → J/ψK * 0 decays. The LHCb collaboration has recently presented pioneering results on this topic. We analyse their implications and present a roadmap for controlling the penguin effects.

CP violation in the Bs0 system

“…(Fleischer, 1999b)) or B 0 s → J/ψK * (892) (see e.g. (De Bruyn and Fleischer, 2015;Dunietz et al, 2001;Faller et al, 2009a)). In the first decay there is only one vector particle in the final state, while the latter case we have two (K * (892) is a vector meson) as in the case of B 0 s → J/ψφ.…”

“…The corresponding branching ratios have been measured earlier by the LHCb Collaboration (Aaij et al, 2012c,e). (De Bruyn and Fleischer, 2015) discuss some strategies to extract the size of penguin pollution without having the full knowledge about these CP asymmetries. A further drawback of this method is that the size of the hadronic effects due to the exchange of a φ-meson with aK * (892)-meson cannot be quantified from first principles.…”

“…The application of these symmetry is quite widespread, see e.g. (Bhattacharya et al, 2013;Ciuchini et al, 2005Ciuchini et al, , 2011De Bruyn and Fleischer, 2015;Faller et al, 2009a;Fleischer, 1999b;Jung, 2012;Ligeti and Robinson, 2015) for some examples related to B-meson decays. Again a word of caution: it is currently not clear how well the SU (3) F -symmetry is working and how large the corrections are, see e.g.…”

In pursuit of new physics with B s,d 0 → ℓ + ℓ −

“…Current experimental information from B 0 s → J/ψφ and decays with similar dynamics gives the following results [16,18,19]:…”

“…It is impressive to see the impact of the future extraction of γ, allowing a very precise determination of R t . For completeness, in the right panel of figure 4, we show other constraints in theρ-η plane following from ∆M s /∆M d and the determination of the CKM angle β = (21.6 ± 0.9) • through CP violation in B 0 d → J/ψK 0 S decays, taking penguin effects into account [18]. For comprehensive analyses of the UT, the reader is referred to refs.…”