Strangeness measurements of kaon pairs, CP violation and Bell inequalities

TL;DR

This paper reviews how neutral kaon pairs can be used to test quantum nonlocality and Bell inequalities, highlighting the unique features and differences from photon-based systems, and discussing two types of Bell inequalities related to kaon properties.

Contribution

It introduces two types of Bell inequalities tailored for kaon systems, considering their time evolution and internal symmetries, advancing quantum nonlocality tests in high energy physics.

Findings

Kaon pairs can test quantum nonlocality in high energy physics.

Violation of CP symmetry relates to Bell inequality violations.

Two Bell inequalities are proposed for kaon systems.

Abstract

The nonlocal property of quantum mechanics can be nicely tested in high energy physics; in particular, the neutral kaon pairs as produced at DA$\Phi$NE, Frascati, are very well suited. The analogies of kaons as compared to polarized photons or spin--1/2 particles --the kaonic qubit feature-- are reviewed. However, there are also fundamental differences which occur due to the kaon time evolution and due to internal symmetries; in particular, the violation of CP symmetry is related to the violation of Bell inequalities. Two type of Bell inequalities for kaons are presented, one for the variation of the ``quasi--spin'' and the other for different detection times of the kaon.