Mark Brettell | Search arXiv

arXiv2026

Probing Matter Unification through Higgs Physics at the LHC

We investigate the Higgs sector phenomenology of the minimal low scale quark-lepton unification theory. In addition to the Standard Model-like Higgs boson, the theory predicts a new CP-even neutral Higgs, a CP-odd neutral Higgs, and two charged Higgses, together with heavy right-handed neutrinos and leptoquarks. We analyze the scalar spectrum, the Yukawa structure responsible for charged-fermion masses, and the neutrino sector realized through an inverse-seesaw mechanism, emphasizing that the couplings of the new Higgs bosons are directly tied to the structure of matter unification and therefore lead to characteristic decay patterns dominated by third-generation fermions. We compute the branching ratios and production cross sections of the new Higgs states at the Large Hadron Collider (LHC) and assess their impact on present and future collider measurements. We find that current LHC data probe significant regions of parameter space for the neutral heavy Higgs bosons, with the strongest sensitivity arising from channels involving tau leptons, tops, and related final states, while the charged Higgs remains less constrained because of its electroweak production mechanism. Our results show that Higgs measurements provide a powerful and complementary probe of low-scale matter unification beyond direct leptoquark searches and open a new avenue for testing quark-lepton unification at present and future colliders, with discovery potential in high-luminosity LHC running.

hep-ph↗

arXiv2025

Sterile-active resonance: A global qualitative picture

In the $ν$SM extended by adding an eV-scale sterile state, the $(3+1)$ model, the sterile-active level crossing entails the MSW resonance, here referred as the sterile-active (SA) resonance. In this paper, we construct an effective theory of SA resonance which involves only the sterile-active mixing angles and $Δm^2_{41}$, thanks to the given environment of high matter potential which freezes the $ν$SM oscillations. We give our first attempt at an analytic treatment of the effective theory to illuminate the global picture of the SA resonance at a glance. We formulate a perturbative framework in which the structure of ``texture zeros'' of the $S$ matrix in the flavor space and the suppression by the small parameters $\sin θ_{j 4}$ ($j=1,2,3$) allows us to reveal the flavor$-$event-type hierarchy of the resonance-effect strength in the probabilities. We have shown that the cascade events dominantly comes from the three paths through $P(ν_{e} \rightarrow ν_{e})$, $P(\barν_{e} \rightarrow \barν_{e})$, and $P(\barν_μ \rightarrow \barν_τ)$, and a three-component fit is suggested to disentangle the SA resonance generation mechanisms.

hep-ph↗