On the ultimate precision of meson mixing observables

TL;DR

This paper assesses the limits of theoretical precision in meson mixing observables, proposing a model for duality violations and exploring their implications for new physics detection and charm sector discrepancies.

Contribution

It introduces a simple model for duality violations in meson mixing and provides bounds on these effects, highlighting their impact on interpreting experimental results.

Findings

Bounds on duality violation effects in mixing observables

Potential signals of new physics in future measurements

Explanation of D-mixing discrepancies with modest duality violation

Abstract

Meson mixing is considered to be an ideal candidate for new physics searches. Current experimental precision has greatly increased over the recent years, excelling in several cases the theoretical precision. A possible limit in the theoretical accuracy could be a hypothetical breakdown of quark-hadron duality. We propose a simple model for duality violations and give stringent bounds on such effects for mixing observables, indicating regions, where future measurements of $\Delta \Gamma_d$, $a_{sl}^d$ and $a_{sl}^s$ would be clear signals of new physics. Finally, we turn our attention to the charm sector, and reveal that already a modest duality violation of about $20 \%$ could explain the huge difference between HQE predictions for D-mixing and experimental data.