In pursuit of new physics with Bd0→J/ψK0 and Bs0→J/ψϕ decays at the high-precision Frontier

• Published in: Journal of physics. G, Nuclear and particle physics Nuclear and particle physics, 2021-06, Vol.48 (6), p.65002
• Main Authors: Barel, Marten Z, De Bruyn, Kristof, Fleischer, Robert, Malami, Eleftheria
• Format: Article
• Language: English
• Subjects: CP violation; flavour physics; meson decays; penguin topologies
• ISSN: 0954-3899; 1361-6471
• DOI: 10.1088/1361-6471/abf2a2

The decays B d 0 → J / ψ K S 0 and B s 0 → J / ψ ϕ play a key role for the determination of the B q 0 – B ̄ q 0 ( q = d , s ) mixing phases ϕ d and ϕ s , respectively. The theoretical precision of the extraction of these quantities is limited by doubly Cabibbo-suppressed penguin topologies, which can be included through control channels by means of the SU (3) flavour symmetry of strong interactions. Using the currently available data and a new simultaneous analysis, we discuss the state-of-the-art picture of these effects and include them in the extracted ϕ q values. We have a critical look at the standard model predictions of these phases and explore the room left for new physics. Considering future scenarios for the high-precision era of flavour physics, we illustrate that we may obtain signals for physics beyond the standard model with a significance well above five standard deviations. We also determine effective colour-suppression factors of B d 0 → J / ψ K 0 , B s 0 → J / ψ K S 0 and B d 0 → J / ψ π 0 decays, which serve as benchmarks for QCD calculations of the underlying decay dynamics, and present a new method using information from semileptonic B d 0 → π − ℓ + ν ℓ and B s 0 → K − ℓ + ν ℓ decays.