Learning from Radiation at a Very High Energy Lepton Collider

TL;DR

This paper explores how high-energy lepton colliders can probe short-distance physics through Electroweak radiation patterns, emphasizing the importance of resummed theoretical predictions and the interplay with new physics signals.

Contribution

It introduces a method to incorporate radiation effects at double logarithmic order and demonstrates how radiation patterns can improve sensitivity to new physics at future colliders.

Findings

Resummed radiation effects are crucial for accurate predictions.

Radiation patterns can reveal short-distance physics influences.

Combined measurements enhance sensitivity to new interactions.

Abstract

We study the potential of lepton collisions with about $10\text{ TeV}$ center of mass energy to probe Electroweak, Higgs and Top short-distance physics at the $100\text{ TeV}$ scale, pointing out the interplay with the long-distance ($100\text{ GeV}$) phenomenon of Electroweak radiation. On one hand, we find that sufficiently accurate theoretical predictions require the resummed inclusion of radiation effects, which we perform at the double logarithmic order. On the other hand, we notice that short-distance physics does influence the emission of Electroweak radiation. Therefore the investigation of the radiation pattern can enhance the sensitivity to new short-distance physical laws. We illustrate these aspects by studying Effective Field Theory contact interactions in di-fermion and di-boson production, and comparing cross-section measurements that require or that exclude the emission of massive Electroweak bosons. The combination of the two types of measurements is found to enhance the sensitivity to the new interactions. Based on these results, we perform sensitivity projections to Higgs and Top Compositeness and to minimal $Z'$ new physics scenarios at future muon colliders.