A new B-flavour anomaly in Bd,s → $$ {K}^{\ast 0}{\overline{K}}^{\ast 0} $$: anatomy and interpretation

In the context of the recently measured non-leptonic decays Bd→$$ {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ K ∗ 0 K ¯ ∗ 0 and Bs→$$ {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ K ∗ 0 K ¯ ∗ 0 we analyse the anatomy of the LVV observable that compares the longitudinal components of Bs→VV and Bd→VV decays. This observable is cleaner than the longitudinal polarisation fraction as it is afflicted only at subleading order in a 1/mb expansion by the theoretical uncertainties arising in the transverse components entering the polarisation fraction. Focusing on the particular case of Bd→$$ {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ K ∗ 0 K ¯ ∗ 0 and Bs→$$ {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ K ∗ 0 K ¯ ∗ 0 , we discuss the main sources of hadronic uncertainty in the SM. We find for the SM prediction $$ {L}_{K^{\ast }{\overline{K}}^{\ast }}={19.5}_{-6.8}^{+9.3} $$ L K ∗ K ¯ ∗ = 19.5 − 6.8 + 9.3 , which implies a 2.6σ tension with respect to the most recent data, pointing to a deficit in the b→s transition of the non-leptonic decay versus the corresponding b→d transition. We discuss possible New Physics explanations for this deviation, first at the level of the Weak Effective Theory and we identify that the two Wilson coefficients $$ {\mathcal{C}}_4 $$ C 4 and $$ {\mathcal{C}}_{8g} $$ C 8 g can play a central role in explaining this anomaly. Finally, we briefly explore two different simplified New Physics models which can explain the anomaly through a contribution either in $$ {\mathcal{C}}_4 $$ C 4 (Kaluza-Klein gluon) or in $$ {\mathcal{C}}_{8g} $$ C 8 g , with a significant amount of fine tuning, but possible connections to the b→sℓℓ anomalies.

EXTRACTING THE CKM PHASE ANGLE γ(≡ φ3) FROM ISOSPIN ANALYSIS IN B → Kπ DECAY

We propose a new method to extract the CKM phase angle γ(≡ φ3) from the isospin analysis in B → Kπ decays only. Unlike previously proposed methods, we do not employ flavor SU (3) symmetry, so that this method is free from the hadronic uncertainty coming from the SU (3) breaking effect. Neither we adopt any Dalitz-plot analysis, which may involve multiple strong phases and large final state interactions. Since no theoretical assumption, except the isospin relations, is imposed on B → Kπ decays, this method will work well, regardless of possible new physics effects unless the isospin relations do not hold. Since the mixing induced CP asymmetry SKSπ0 plays a crucial role in this method, more precise measurement on SKSπ0 in future experiments will be greatly helpful to extract γ accurately. Using current experimental data for B → Kπ including SKSπ0, we extract γ within [Formula: see text] or [Formula: see text].