Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Transverse spin effects and light-quark dipole moments at colliders

Xin-Kai Wen, Bin Yan, Zhite Yu, C. -P. Yuan

Abstract

In this talk, we present novel methods to investigate light-quark dipole interactions at colliders. Our approach includes: (1) measuring azimuthal asymmetries of a collinear dihadron in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider, and (2) utilizing azimuthal asymmetries of dihadron $(h_1 h_2)$ produced in association with an additional hadron $h^\prime$ at lepton colliders. These asymmetries provide a unique means to observe transversely polarized quarks, which arise from quantum interference and are exclusively sensitive to dipole interactions at the leading power of the new physics scale. Consequently, they exhibit a linear dependence on the dipole couplings, free from contamination by other new physics effects. This approach has the potential to significantly strengthen current constraints by one to two orders of magnitude. By combining all possible channels of $h^\prime$, this novel approach enables the disentanglement of the up- and down-quark dipole moments. Additionally, by controlling the electron's longitudinal polarization and the center-of-mass energy, it separates the contributions mediated by photon and weak boson. Furthermore, it allows for a simultaneous determination of both real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential $CP$-violating effects at high energies.

Transverse spin effects and light-quark dipole moments at colliders

Abstract

In this talk, we present novel methods to investigate light-quark dipole interactions at colliders. Our approach includes: (1) measuring azimuthal asymmetries of a collinear dihadron in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider, and (2) utilizing azimuthal asymmetries of dihadron produced in association with an additional hadron at lepton colliders. These asymmetries provide a unique means to observe transversely polarized quarks, which arise from quantum interference and are exclusively sensitive to dipole interactions at the leading power of the new physics scale. Consequently, they exhibit a linear dependence on the dipole couplings, free from contamination by other new physics effects. This approach has the potential to significantly strengthen current constraints by one to two orders of magnitude. By combining all possible channels of , this novel approach enables the disentanglement of the up- and down-quark dipole moments. Additionally, by controlling the electron's longitudinal polarization and the center-of-mass energy, it separates the contributions mediated by photon and weak boson. Furthermore, it allows for a simultaneous determination of both real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential -violating effects at high energies.
Paper Structure (5 sections, 11 equations, 3 figures)

This paper contains 5 sections, 11 equations, 3 figures.

Table of Contents

  1. Introduction
  2. A Hint from Lepton Dipole Moment
  3. Light Quark Dipole Moment at EIC
  4. Light Quark Dipole Moment at Lepton Colliders
  5. Summary and Prospects

Figures (3)

  • Figure 1: (a) Kinematic configuration of scattering; (b) Chirality-flip EW dipole interaction; (c) and (d) Expected constraints from SSAs on real and imaginary parts of $\Gamma_{Z,\gamma}^{e}$ in opposite-spin case.
  • Figure 2: (a) LO kinematic configuration of the dihadron production in SIDIS; (b) LO cut diagram representation of Eq. \ref{['eq:diXsec_SIDIS']}; (c) and (d) Expected constraints on real and imaginary parts of quark dipole couplings.
  • Figure 3: (a) LO kinematic configuration of associated $(h_1 h_2)h'$ production; (b) LO cut diagram representation in Eq. \ref{['eq:diXsec_SIA']}; (c) and (d) Expected constraints on real and imaginary parts of light-quark dipole couplings.