The $B^{+}\to K^{+}\nu \bar{\nu }$ decay as a search for the QCD axion

Abstract

We introduce a model-independent framework to reinterpret Belle II results using only public data, analytically reconstructing the mapping between true and reconstructed kinematic variables within the statistically dominant Inclusive Tagging Analysis. This enables rare-decay measurements to probe light invisible particles -- such as the QCD axion or axion-like particles, collectively denoted $a$ -- without relying on internal simulations. Applying the method to $B^{+}\to K^{+}\nu \bar{\nu }$ yields the strongest bound on the branching fraction for $B^{+}\to K^{+}a$, improving existing limits by about a factor of nine and constraining the axion's fundamental flavour-changing coupling to $b$ and $s$ quarks. The approach establishes $B^{+}\to K^{+}\nu \bar{\nu }$ as a dual probe -- simultaneously testing short-distance new physics and light invisible states, the two probes working independently to an excellent approximation -- and provides a general strategy for model-independent reinterpretation of collider data.

arXiv comment10 pages, 6 figures. Matches journal version

References in corpus (23)

• Axion Cosmology
• New experimental approaches in the search for axion-like particles
• The landscape of QCD axion models
• Astrophysical Axion Bounds
• Invisible Axion Search Methods
• Two-Loop Electroweak Corrections for the K -> pi nu anti-nu Decays
• Recent Progress in the Physics of Axions and Axion-Like Particles
• Quark Flavor Phenomenology of the QCD Axion
• On the Standard Model prediction for BR(B{s,d} to mu+ mu-)
• The Search for Feebly-Interacting Particles
• The Full Event Interpretation -- An exclusive tagging algorithm for the Belle II experiment
• Evidence for $B^{+}\to K^{+}\nu \bar{\nu }$ decays
• Revisiting $B\to K^{(\ast )}\nu \bar{\nu }$ decays in the Standard Model and beyond
• Effects of theta on the deuteron binding energy and the triple-alpha process
• Standard Model predictions for $B\to K{\ell }^{+}{\ell }^{-}$, $B\to K{\ell }_1^{-}{\ell }_2^{+}$ and $B\to K\nu \bar{\nu }$ using form factors from $N_f=2+1+1$ lattice QCD
• Dispersive Analysis of $B\to K^{(\ast )}$ and $B_s\to \varphi$ Form Factors
• Search for $B^{+}\to K^{+}\nu \bar{\nu }$ decays using an inclusive tagging method at Belle II
• Track Finding at Belle II
• Search for $B^{+}\to {\mu }^{+}{\nu }_{\mu }$ and $B^{+}\to {\mu }^{+}N$ with inclusive tagging
• Decoding the $B\to K\nu \nu$ excess at Belle II: kinematics, operators, and masses
• Displaced or invisible? ALPs from $B$ decays at Belle II
• Some Remarks on Anthropic Approaches to the Strong CP Problem
• Impact of new invisible particles on $B\to K^{(\ast )}{E}_{\mathrm{miss}}$ observables

Cited by in corpus (1)

• Lecture notes on Machine Learning applications for global fits