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

A bstract In the context of recently measured non-leptonic decays B d ? $$ {K}^{\ast 0}{\overline{K}}^{\ast 0} K ? 0 ¯ and s we analyse anatomy L VV observable that compares longitudinal components decays. This is cleaner than polarisation fraction as it afflicted only at subleading order in a 1 /m b expansion by theoretical uncertainties arising transverse entering fraction. Focusing on particular case , discuss main sources hadronic uncertainty SM. We find for SM prediction {L}_{K^{\ast }{\overline{K}}^{\ast }}={19.5}_{-6.8}^{+9.3} L = 19.5 ? 6.8 + 9.3 which implies 2 . 6 ? tension with respect to most recent data, pointing deficit transition decay versus corresponding transition. possible New Physics explanations this deviation, first level Weak Effective Theory identify two Wilson coefficients {\mathcal{C}}_4 C 4 {\mathcal{C}}_{8g} 8 g can play central role explaining anomaly. Finally, briefly explore different simplified models explain anomaly through contribution either (Kaluza-Klein gluon) or significant amount fine tuning, but connections ?? anomalies.