Visible Effects of Invisible Hidden Valley Radiation

TL;DR

This paper investigates how radiation in a Hidden Valley sector can influence observable collider signatures, affecting the interpretation of particle masses and revealing potential new physics beyond the Standard Model.

Contribution

It introduces a generic SU(N)-like Hidden Valley model implemented in Pythia to study the collider signatures of hidden sector radiation effects.

Findings

Hidden Valley radiation significantly alters visible particle kinematic distributions

Misinterpretation of these effects can lead to incorrect mass inferences

Both e+e- and LHC colliders show observable impacts of hidden sector radiation

Abstract

Assuming there is a new gauge group in a Hidden Valley, and a new type of radiation, can we observe it through its effect on the kinematic distributions of recoiling visible particles? Specifically, what are the collider signatures of radiation in a hidden sector? We address these questions using a generic SU(N)-like Hidden Valley model that we implement in Pythia. We find that in both the e+e- and the LHC cases the kinematic distributions of the visible particles can be significantly affected by the valley radiation. Without a proper understanding of such effects, inferred masses of "communicators" and of invisible particles can be substantially off.