Searches for Contact Interactions at HERA

TL;DR

This paper reports on searches for contact interactions at HERA, analyzing high Q^2 scattering events to test for physics beyond the Standard Model, setting limits on various new physics models.

Contribution

It provides the first comprehensive limits on contact interactions, leptoquarks, extra dimensions, and quark charge radius using HERA data.

Findings

No significant deviations from Standard Model predictions.

Limits set on compositeness scale and other new physics parameters.

Constraints on models with large extra dimensions and quark substructure.

Abstract

The H1 and ZEUS collaborations at HERA have searched for signatures of physics beyond the Standard Model with high Q^2 neutral current deep inelastic electron-proton and positron-proton scattering events. No significant deviations from Standard Model predictions were observed. Various eeqq contact nteraction models have been considered. Limits on the compositeness scale in general eeqq contact interaction models, mass to the Yukawa coupling ratio for heavy leptoquarks, the effective Planck mass scale in models with large extra dimensions and the effective quark charge radius are presented.