CP Violation in Charmless $b \to s\bar qq$ Transitions

With the study of CP violation in $b\to d$ transitions seemingly in good agreement with Standard Model (SM) expectations, the subject of CPV studies in charmless $b\to s$ transitions (including $b\bar s \leftrightarrow s\bar b$) is the current frontier of heavy flavor research. Because there is little CPV weak phase in the controlling product of CKM matrix elements for loop-induced $b\to s$ transitions, $V_{ts}^*V_{tb}$, any observed deviation could indicate New Physics. As transitions between $3\to 2$ generation quarks, the subject also has $\tau\to \mu$ transition echoes in the lepton sector, an interesting subject covered in Chap. 9. More generally, with the Sakharov conditions [1] that link CPV with the Baryon Asymmetry of the Universe (BAU), i.e., why there is no trace of antimatter in our Universe, we do expect NP sources for CPV. It is well known that the three generation SM falls short by many orders of magnitude from the CPV that is needed to generate the observed BAU, a point that we will elaborate in Chap. 10. This certainly has been one of the strongest motivations to search for New Physics in CP violation.