Search for effective Lorentz and CPT violation using ZEUS data

TL;DR

This study uses five years of ZEUS data to search for Lorentz and CPT violation effects in quark interactions, finding no evidence but setting new constraints on theoretical coefficients.

Contribution

First-time constraints are placed on 42 coefficients describing CPT and Lorentz violation in light quark interactions using HERA data.

Findings

No sidereal time oscillations observed within uncertainties.

Constraints established on 42 Lorentz and CPT violation coefficients.

Most constraints are reported for the first time.

Abstract

Lorentz and CPT symmetry in the quark sector of the Standard Model are studied in the context of an effective field theory using ZEUS $e^{\pm} p$ data. Symmetry-violating effects can lead to time-dependent oscillations of otherwise time-independent observables, including scattering cross sections. An analysis using five years of inclusive neutral-current deep inelastic scattering events corresponding to an integrated HERA luminosity of $372\; \text{pb}^{-1}$ at $\sqrt{s} = 318$ Gev has been performed. No evidence for oscillations in sidereal time has been observed within statistical and systematic uncertainties. Constraints, most for the first time, are placed on 42 coefficients parameterising dominant CPT-even dimension-four and CPT-odd dimension-five spin-independent modifications to the propagation and interaction of light quarks.