Tripartite entanglement and Bell non-locality in loop-induced Higgs boson decays

TL;DR

This paper investigates quantum entanglement and Bell non-locality in rare three-body Higgs decays within the Standard Model with CP violation, revealing entanglement structures and potential for fundamental tests at colliders.

Contribution

It introduces novel entanglement observables for three-body Higgs decays and analyzes their structure and implications for quantum correlations in high-energy physics.

Findings

Entanglement can be maximized in specific kinematic configurations.

Decay channels show promise for Bell non-locality tests.

CP effects are suppressed by lepton masses in these observables.

Abstract

In this article, we study quantum entanglement properties of the three-body $H\to\gamma l\bar{l}$ decays (for $l=e,\mu,\tau$) within the context of the Standard Model augmented with CP-violating interactions in the lepton Yukawa sector. Our aim is to elucidate the distribution of entanglement between the final photon, lepton and antilepton across the phase-space. These rare Higgs boson decays occur at 1-loop level, presenting a unique opportunity to scrutinize quantum correlations of fundamental interactions in tripartite systems by computing concurrence measures and investigating Bell non-locality. Moreover, we explore post-decay and autodistillation phenomena. Multipartite entanglement measures have much richer structure than those in the bipartite case, thus deserve more attention in collider phenomenology. In this line, we analyze here novel observables for these three-body Higgs boson decays, which can be extended to other multiparticle systems within the high-energy regime. We found that entanglement manifests among final particles, occasionally achieving a maximally entangled state in specific kinematical configurations. Also, these decay channels are promising for Bell non-locality tests but CP-effects are suppressed by lepton masses in this kind of observables.