Usually, effective field theories (EFTs) for axion-like particles (ALPs) are built assuming a shift symmetry for the ALP due to the global U(1) Peccei-Quinn (PQ) symmetry that is at the heart of the axion mechanism. However, it is generally believed that global symmetries, in particular axion shift symmetries, can only be approximate. Therefore, it is important to include shift-breaking...

In view of the latest experimental results recently released by the ATOMKI collaboration, we critically re-examine the possible theoretical interpretation of the observed anomalies in terms of a new BSM boson X with mass ∼ 17 MeV. Employing a multipole expansion method, we estimate the range of values of the nucleon couplings to the new light state in order to match the experimental...

We explore the potential of the ratios $R^{\tau \mu}$ in the decays $B \to K \ell \ell$ and $B \to K^* \ell \ell$ ($\ell=\mu,\tau$) as a means to probe new physics effects within the $\tau-\mu$ sector.We find that these ratios deviate from their SM predictions even for universal couplings. This indicates that the observed deviation of these ratios from their SM predictions alone is...

The rare $B \to K^{(*)} \bar{\ell} \ell$ decays exhibit a long-standing tension with Standard Model (SM) predictions, which can be attributed to a lepton-universal short-distance $b \to s \bar{\ell} \ell$ interaction.

We present two novel methods to disentangle this effect from long-distance dynamics: one based on the determination of the inclusive $b \to s \bar{\ell} \ell$ rate at high...