Enhanced CP asymmetries in $$B \rightarrow K \mu ^+ \mu ^-$$ B → K μ + μ -

Abstract

Abstract We show that the current values of $$R_K^\mathrm {exp}$$ R K exp and $$R_{K^*}^\mathrm {exp}$$ R K ∗ exp can be accommodated by allowing a nonzero New Physics coupling $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ to be complex, both in the scenario in which only $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ is affected, and in the scenario with complex $$\delta C_{9,10}^{\mu \mu }$$ δ C 9 , 10 μ μ satisfying $$\delta C_{9}^{\mu \mu }=-\delta C_{10}^{\mu \mu }$$ δ C 9 μ μ = - δ C 10 μ μ . A presence of the weak CP-violating phase can then be tested by measuring the CP-asymmetry, $$\mathcal {A}_\mathrm {CP}$$ A CP . We show that this asymmetry is enhanced around the peak of each $$c\bar{c}$$ c c ¯ -resonance, and in fact more pronounced in the close vicinity of $$J/\psi $$ J / ψ and $$\psi (2S)$$ ψ ( 2 S ) . Therefore, measuring $$\mathcal {A}_\mathrm {CP}$$ A CP before and after the resonances’ peak could be revelatory of the CP-violation that originates from beyond the Standard Model, or to be a significant constrain when building a realistic scenario of New Physics.