Lorentz and CPT violation in partons

Abstract

A framework is presented for the factorization of high-energy hadronic processes in the presence of Lorentz and CPT violation. The comprehensive effective field theory describing Lorentz and CPT violation, the Standard-Model Extension, is used to demonstrate factorization of the hadronic tensor at leading order in electroweak interactions for deep inelastic scattering and for the Drell-Yan process. Effects controlled by both minimal and nonminimal coefficients for Lorentz violation are explored, and the equivalent parton-model description is derived. The methodology is illustrated by determining cross sections and studying estimated attainable sensitivities to Lorentz violation using real data collected at the Hadronen-Elektronen Ring Anlage and the Large Hadron Collider and simulated data for the future US-based electron-ion collider.√ 2 (γ 0 + γ 3 ), γ i ⊥ = γ 1 , γ 2 . The ellipses

Quark-sector Lorentz violation in Z-boson production

“…The same considerations apply to the partonic cross sections σ f (ξ, ξ ). These former features can be understood in the context of local and Lorentz observer-invariant operator products [43,45],…”

“…Constraints on heavy quarks are sparse in comparison to light quarks, however, a few bounds have been extracted from e + e − collisions at the Large Electron-Positron Collider (LEP), tt production at the Fermi National Accelerator Laboratory (Fermilab) and the LHC, radiative corrections, and potentially stable top hadrons from astrophysical sources [37][38][39][40][41][42]. Direct probes of minimal and nonminimal effects on initial-state partons can also be made through measurements of the scattering cross section in deep inelastic scattering and the DY process [43][44][45]. Collider processes such as these offer a complementary approach for constraining the space of parton coefficients, as the majority of existing quark-sector bounds from astrophysical sources are limited to the subset of isotropic (rotationally-invariant) coefficients.…”

“…In this work, we extend the recently developed formalism for addressing CPT-and Lorentz-violating effects in the collisions of high-energy hadrons at large momentum transfer [45] to include spin-dependent effects. Precisely, we consider a set of dimensionless, CPT-even, parity-odd, and spin-dependent minimal SME coefficients affecting the propagation and interactions of quarks in the neutral-current DY process.…”

“…The framework for the description of scattering in the presence of flavor-diagonal and spinindependent CPT-and Lorentz-violating operators of arbitrary mass dimension was recently developed in ref. [45]. We extend this approach by including minimal spin-dependent interactions, which requires additional attention.…”

“…W − e f sin 2 θ W , and g f R = −e f sin 2 θ W . At energies much greater than the hadron masses the differential cross section reads [45]. The amplitude has the form…”