Displaced or invisible? ALPs from $B$ decays at Belle II

Abstract

At colliders, neutral long-lived particles can be detected through displaced decay products or as missing energy. Which search strategy is better depends on the particle's decay length just as on the detector properties. We investigate the complementarity of displaced and invisible signatures for the Belle II experiment. Focusing on axion-like particles $a$ produced from meson decays, we present a new search strategy for two-body decays $B^{+}\to K^{+}a,a\to E/$ with missing energy $E/$. With $50$ab${}^{-1}$ of data, Belle II can probe light invisible resonances with branching ratio $\mathcal{B}(B^{+}\to K^{+}a)\gtrsim 10^{-7}$ and decay length $c{\tau }_a\gtrsim 1$m. For axion-like particles, we expect the sensitivity of $B^{+}\to K^{+}E/$ to small couplings to improve by up to two orders of magnitude compared to previous searches at collider and fixed-target experiments. For sub-GeV particles, $B^{+}\to K^{+}E/$ at Belle II and searches at beam-dump experiments are most sensitive; for heavier particles, searches for displaced vertices at Belle II, long-lived particle experiments at the LHC, and future fixed-target experiments can probe the smallest couplings.

30 pages, 12 figures, 1 table

References in corpus (26)

• An Introduction to PYTHIA 8.2
• Constraints on Dark Matter from Colliders
• Collider Probes of Axion-Like Particles
• Maverick dark matter at colliders
• Feebly-Interacting Particles:FIPs 2020 Workshop Report
• Revised constraints and Belle II sensitivity for visible and invisible axion-like particles
• The Low-Energy Effective Theory of Axions and ALPs
• Flavor probes of axion-like particles
• Quark Flavor Phenomenology of the QCD Axion
• A New Flavor of Searches for Axion-Like Particles
• The Search for Feebly-Interacting Particles
• Robust cosmological constraints on axion-like particles
• Running in the ALPs
• Heavy axion-like particles and core-collapse supernovae: constraints and impact on the explosion mechanism
• Invisible and displaced dark matter signatures at Belle II
• Minimal Flavor Violation with Axion-like Particles
• Track Finding at Belle II
• Supernova bound on Axion-Like Particles coupled with electrons
• Cosmological constraints on decaying axion-like particles: a global analysis
• Long-lived Dark Higgs and Inelastic Dark Matter at Belle II
• Heavy QCD Axion at Belle II: Displaced and Prompt Signals
• Cosmological Implications of Axion-Matter Couplings
• Unleashing the full power of LHCb to probe Stealth New Physics
• Complete theory of radiative corrections to $K_{\ell 3}$ decays and the $V_{us}$ update
• Higgs portal to dark matter and $B\to K^{(\ast )}$ decays
• $\tau \to \ell +$ invisible through invisible-savvy collider variables

Cited by in corpus (10)

• When Energy Goes Missing: New Physics in $b\to s\nu \nu$ with Sterile Neutrinos
• Phenomenology of axion-like particles with universal fermion couplings -- revisited
• Top Secrets: Long-Lived ALPs in Top Production
• The first limit on invisible decays of $B_s$ mesons comes from LEP
• Search for a long-lived spin-0 mediator in $b\to s$ transitions at the Belle II experiment
• Precise tests of the axion coupling to tops
• ALP-ine quests at the LHC: hunting axion-like particles via peaks and dips in $t\bar{t}$ production
• Resonant ALP-Portal Dark Matter Annihilation as a Solution to the $B^{\pm }\to K^{\pm }\nu \bar{\nu }$ Excess
• The $B^{+}\to K^{+}\nu \bar{\nu }$ decay as a search for the QCD axion
• Systematic analysis of search strategies for $L_{\mu }-L_{\tau }$ gauge bosons at Belle II