Poulose Poulose

We study the theoretical constraints on the scalar sector of the alternative left-right model (ALRM), an E 6 -motivated extension of the Standard Model based on the gauge group S U ( 3 ) c ⊗ S U ( 2 ) L ⊗ S U ( 2 ) R ′ ⊗ U ( 1 ) B − L , supplemented by a global U ( 1 ) S symmetry. We derive the complete set of tree-level perturbative unitarity constraints on the model, resulting in 14 independent conditions on the quartic scalar couplings. When combined with the boundedness-from-below conditions and the requirement of positive-definite scalar mass-squared eigenvalues, this yields significantly more stringent restrictions on the parameter space than either set alone. We then perform a one-loop renormalization group analysis, evolving the model parameters up to a high-energy cutoff scale, and requiring that the vacuum stability, the unitarity, and the perturbativity conditions are preserved throughout. The renormalization group evolution is found to restrict the allowed parameter space considerably beyond the tree-level bounds, with the constraints on the quartic couplings becoming more stringent as the cutoff scale is raised. Consequently, the physical scalar masses in the model acquire upper bounds. For the right-hand symmetry breaking scale, v R = 10 TeV and requiring theoretical consistency up to 10 16 GeV , we obtain m H 1 ± ≲ 6.5 TeV , m H 2 ± ≲ 1.5 TeV , and m H 1 0 ≃ m A 1 ≲ 1.5 TeV , with all bounds scaling with v R . These findings offer a predictive and falsifiable framework for searches of the extended Higgs sector of the ALRM at the current and future collider experiments.

We propose a novel framework for low-scale leptogenesis within an extension of the Standard Model that includes three S U ( 2 ) singlet right-handed neutrinos, a singlet vectorlike neutral fermion, and a real scalar field. In this setup, the C P asymmetry arises through a rich interplay of mechanisms, including two-body decays of the lightest right-handed neutrino into leptons and Higgs boson or into dark-sector particles, as well as multiple 2 → 2 scattering processes involving visible and dark sector particles. Crucially, the C P -violating phases originate not only from conventional vertex and self-energy corrections of the decay of the right-handed neutrinos but also from novel interference effects in the scattering processes mediated by the dark sector, which significantly enrich the sources of asymmetry. A distinctive feature of our framework is the direct connection between the dark sector and leptogenesis, providing a unified explanation for both the matter–antimatter asymmetry and Dark Matter abundance. Moreover, the viable parameter range including the mass spectrum is within the range that Large Hadron Collider can explore.

We explore constraints on the parameter space of the alternative left-right model originating from the leptonic sector. Our analyses focuses on both lepton-flavor-conserving observables, particularly the anomalous magnetic moment of the muon, and lepton-flavor-violating processes like μ → e γ decay and μ − e conversions in nuclei. While contributions to the anomalous magnetic moment fall below the measured values at 2 σ , current and future experimental sensitivities to flavor-violating branching rations of the Standard Model leptons are expected to impose lower bounds on the mass of the peculiar S U ( 2 ) R gauge boson of the model. This provides complementary constraints relative to existing limits, which are indirect and derived from collider bounds on the mass of the associated neutral gauge boson Z ′ . Published by the American Physical Society 2025

The Alternative Left-Right Model is an attractive variation of the usual Left-Right Symmetric Model because it avoids flavour-changing neutral currents, thus allowing the additional Higgs bosons in the model to be light. We show here that the model predicts several dark matter candidates naturally, through introduction of an R-parity similar to the one in supersymmetry, under which some of the new particles are odd, while all the SM particles are even. Dark matter candidates can be fermionic or bosonic. We present a comprehensive investigation of all possibilities. We analyze and restrict the parameter space where relic density, direct and indirect detection bounds are satisfied, and investigate the possibility of observing fermionic and bosonic dark matter signals at the LHC. Both the bosonic and fermionic candidates provide promising signals, the first in LHC at 300 fb⁻¹, the second at higher luminosity, 3000 fb⁻¹. Signals from bosonic candidates are indicative of the presence of exotic d′ quarks, while fermionic candidates imply the existence of charged Higgs bosons, all with masses in the TeV region.

We investigate an Alternative Left-Right Model (ALRM) with SU(2)_L as well as SU(2)_R gauge groups, but unlike the traditional left-right symmetric models (LRSM) is not symmetric under the exchange of the fermion content. Interestingly, it can be embedded in E₆, while its low energy Higgs structure resembles the LRSM, involving Higgs doublets χ_L,R and one Higgs bidoublet Φ. We analyze the scalar potential and the vacuum structure of the theory analytically to ensure the stability of scalar potential via bounded from below (BFB) and copositivity criteria, accompanied by a numerical study. We establish the necessary criteria for electric charge-preserving vacua, yielding constraints on various coupling parameters of the theory. Finally we obtain constraints on the parameters of the model from collider data on the masses of the Higgs scalars.