New spectra in the HEIDI Higgs models

TL;DR

This paper investigates HEIDI models, which extend the standard model with higher-dimensional scalar fields, analyzing their spectral densities and compatibility with LEP-2 data, revealing potential multi-peak Higgs spectra and strong higher-dimensional interactions.

Contribution

It introduces an extended HEIDI model with a higher-dimensional mixing parameter, analyzing spectral densities and their experimental implications, especially regarding multiple Higgs peaks.

Findings

Spectral densities can have one, two, or no peaks plus a continuum.

The new mass scale is approximately 56 GeV with a 12 GeV uncertainty.

Higher-dimensional coupling constant indicates strong interactions.

Abstract

We study the so-called HEIDI models, which are renormalizable extensions of the standard model with a higher dimensional scalar singlet field. As an additional parameter we consider a higher-dimensional mixing mass parameter. This leads to enriched possibilities compared to a previous study. We find effective spectral densities of the Higgs propagator, consisting of one, two or no particle peaks, together with a continuum. We compare with the LEP-2 data and determine for which range of the model parameters the data can be described. Assuming two peaks to be present we find for the new mass scale $\nu\approx 56\pm12 \gev$, largely independent of the dimension. In the limiting case of $d\rightarrow 6$ and two peaks we find a higher dimensional coupling constant $\alpha_6=0.70 \pm 0.18$, indicative of strong interactions among the higher dimensional fields. The LHC will not be able to study this Higgs field.