Bounds on the Conformal Scale of a Minimally Coupled Dilaton and Multi-Leptonic Signatures at the LHC

TL;DR

This paper investigates the potential to discover a dilaton with mass 200-500 GeV at the LHC within a scale-invariant extension of the Standard Model, analyzing production, decay channels, and current experimental bounds.

Contribution

It provides a detailed analysis of dilaton production and decay at the LHC, extending previous bounds on the conformal scale and exploring detection prospects with early data.

Findings

A conformal scale of 5 TeV is consistent with current data.

Dilaton production via gluon-gluon fusion can lead to multi-leptonic signatures.

Early LHC data (~20 fb$^{-1}$) can probe the allowed parameter space.

Abstract

We explore the potential for the discovery of a dilaton $\mathcal{O}(200-500)$ GeV in a classical scale/conformal invariant extension of the Standard Model by investigating the size of the corresponding breaking scale $\Lambda$ at the LHC, extending a previous analysis. In particular, we address the recent bounds on $\Lambda$ derived from Higgs boson searches. We investigate if such a dilaton can be produced via gluon-gluon fusion, presenting rates for its decay either into a pair of Higgs bosons or into two heavy gauge bosons, which can give rise to multi-leptonic final states. A detailed analysis via PYTHIA-FastJet has been carried out of the dominant Standard Model backgrounds, at a centre of mass energy of 14 TeV. We show that early data of $\sim 20$ fb$^{-1}$ can certainly probe the region of parameter space where such a dilaton is allowed. A conformal scale of 5 TeV is allowed by the current data, for almost all values of the dilaton mass investigated.