Dihadron azimuthal asymmetry and light-quark dipole moments at the Electron-Ion Collider

TL;DR

This paper introduces a new method to measure light-quark dipole moments at the Electron-Ion Collider by analyzing azimuthal asymmetries in hadron pairs, improving sensitivity and enabling $CP$-violation studies.

Contribution

It proposes a novel approach using azimuthal asymmetries to probe light-quark dipole moments, enhancing current constraints and allowing for the measurement of both real and imaginary parts.

Findings

Enhances constraints on light-quark dipole operators by an order of magnitude.

Allows simultaneous determination of real and imaginary dipole couplings.

Provides a new method to investigate $CP$-violating effects at high energies.

Abstract

We propose a novel method to probe light-quark dipole moments by examining the azimuthal asymmetries between a collinear pair of hadrons in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider. These asymmetries provide a means to observe transversely polarized quarks, which arise exclusively from the interference between the dipole and the Standard Model interactions, thereby depending linearly on the dipole couplings. We demonstrate that this novel approach can enhance current constraints on light-quark dipole operators by an order of magnitude, free from contamination of other new physics effects. Furthermore, it allows for a simultaneous determination of both the real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential $CP$-violating effects at high energies.