Non-perturbative Effects on Electroweakly Interacting Massive Particles at Hadron Collider

TL;DR

This paper investigates how non-perturbative effects influence the detection of electroweakly interacting massive particles at hadron colliders, revealing significant impacts on cross section predictions near the EWIMP threshold.

Contribution

The study introduces a non-relativistic effective field theory approach to quantify non-perturbative effects on EWIMP signals in Drell-Yan processes.

Findings

Non-perturbative effects significantly alter the differential cross section near the EWIMP threshold.

Bound states of EWIMPs can form, affecting collider signatures.

Finite energy resolution smears the observable effects at the LHC.

Abstract

Electroweakly Interacting Massive Particles (EWIMPs), in other words, new massive particles that are charged under the electroweak interaction of the Standard Model (SM), are often predicted in various new physics models. EWIMPs are probed at hadron collider experiments not only by observing their direct productions but also by measuring their quantum effects on Drell-Yan processes for SM lepton pair productions. Such effects are known to be enhanced especially when the di-lepton invariant mass of the final state is close to the EWIMP threshold, namely twice the EWIMP mass. In such a mass region, however, we have to carefully take non-perturbative effects into account, because the EWIMPs become non-relativistic and the prediction may be significantly affected by e.g., bound states of the EWIMPs caused by the electroweak interaction. We study such non-perturbative effects using the non-relativistic effective field theory of the EWIMPs, and found that those indeed affect the differential cross section of the Drell-Yan processes significantly, though the effects are smeared due to the finite energy resolution of the lepton measurement at the Large Hadron Collider experiment.