Status and prospects for CPT and Lorentz invariance violation searches in neutral meson mixing

Jeroen Van Tilburg,Maarten Van Veghel

doi:10.1016/j.physletb.2015.01.036

Abstract

An overview of current experimental bounds on CPT violation in neutral meson mixing is given. New values for the CPT asymmetry in the B0 and Bs0 systems are deduced from published BaBar, Belle and LHCb results. With dedicated analyses, LHCb will be able to further improve the bounds on CPT violation in the D0, B0 and Bs0 systems. Since CPT violation implies violation of Lorentz invariance in an interacting local quantum field theory, the observed CPT asymmetry will exhibit sidereal- and boost-dependent variations. Such CPT-violating and Lorentz-violating effects are accommodated in the framework of the Standard Model Extension (SME). The large boost of the neutral mesons produced at LHCb results in a high sensitivity to the corresponding SME coefficients. For the B0 and Bs0 systems, using existing LHCb results, we determine with high precision the SME coefficients that are not varying with sidereal time. With a full sidereal analysis, LHCb will be able to improve the existing SME bounds in the D0, B0 and Bs0 systems by up to two orders of magnitude.

Highlights

In the weak interaction of the Standard Model, the symmetries under transformations of charge conjugation (C ), parity ( P ), and time reversal (T ) are broken
We present an overview of experimental searches for CPT violation in the four neutral meson systems
We have presented new results on 0 s mixing in both the classical and Standard Model Extension (SME) approach, derived from published BaBar, Belle and LHCb results

Summary

Introduction

In the weak interaction of the Standard Model, the symmetries under transformations of charge conjugation (C ), parity ( P ), and time reversal (T ) are broken. CPT symmetry is required by any Lorentz-invariant, local quantum field theory. As CPT violation implies Lorentz violation in an interacting local quantum field theory [1], any CPT-violating observable must break Lorentz invariance. Extension [2,3] (SME), spontaneous CPT violation and Lorentz invariance violation appear in a low-energy effective field theory. In this sense, small CPT-violating effects at low energies provide a window to the quantum gravity scale [4]. From an experimental point of view, the direction dependence results in a modulation with the sidereal phase Such modulations would provide an unambiguous signature of CPT violation. Further improvements are possible with dedicated analyses on the existing 3 fb−1 data set

Formalism

Experimental results and potential measurements

Neutral kaons

Neutral charm

B0 mesons

Conclusion