We offer a new solution to an old puzzle in the penguin-dominated $B\to \pi K$ decays. The puzzle is the inconsistency among the measurements of the branching ratios and $CP$ asymmetries of the four $B\to \pi K$ decays: $B^{+}\to {\pi }^{+}{K}^0$, $B^{+}\to {\pi }^0{K}^{+}$, $B_d^0\to {\pi }^{-}{K}^{+}$, $B_d^0\to {\pi }^0{K}^0$. We solve the $B\to \pi K$ puzzle by considering the effect of an axionlike particle (ALP) that mixes with the ${\pi }^0$ and has mass close to the ${\pi }^0$ mass. We show that the ALP can also explain the anomalies in the electron and muon anomalous magnetic moments.

• Received 9 April 2021
• Accepted 12 August 2021

DOI:https://doi.org/10.1103/PhysRevD.104.L051701

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society