Anatomy of the real Higgs triplet model

Abstract In this article, we examine the Standard Model extended by a Y = 0 real Higgs triplet, the ∆SM. It contains a CP-even neutral Higgs (∆0) and two charged Higgs bosons (∆ ± ), which are quasi-degenerate in mass. We first study the theoretical constraints from vacuum stability and perturbative...

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Main Authors: Saiyad Ashanujjaman, Sumit Banik, Guglielmo Coloretti, Andreas Crivellin, Siddharth P. Maharathy, Bruce Mellado
Format: Article
Language:English
Published: SpringerOpen 2025-04-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP04(2025)003
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author Saiyad Ashanujjaman
Sumit Banik
Guglielmo Coloretti
Andreas Crivellin
Siddharth P. Maharathy
Bruce Mellado
author_facet Saiyad Ashanujjaman
Sumit Banik
Guglielmo Coloretti
Andreas Crivellin
Siddharth P. Maharathy
Bruce Mellado
author_sort Saiyad Ashanujjaman
collection DOAJ
description Abstract In this article, we examine the Standard Model extended by a Y = 0 real Higgs triplet, the ∆SM. It contains a CP-even neutral Higgs (∆0) and two charged Higgs bosons (∆ ± ), which are quasi-degenerate in mass. We first study the theoretical constraints from vacuum stability and perturbative unitarity and then calculate the Higgs decays, including the loop-induced modes such as di-photons (γγ) and Zγ. In the limit of a small mixing between the SM Higgs and ∆0, the latter decays dominantly to WW and can have a sizable branching ratio to di-photon. The model predicts a positive definite shift in the W mass, which is compatible with the current global electroweak fit. At the Large Hadron Collider, it leads to a (i) stau-like signature from pp → ∆+∆ − → τ + τ − ν ν ¯ $$ {\tau}^{+}{\tau}^{-}\nu \overline{\nu} $$ , (ii) multi-lepton final states from pp → γ * → ∆+∆ − → W + W − ZZ and pp → W * → ∆ ± ∆0 → W ± ZW + W − as well as (iii) associated di-photon production from pp → W * → ∆ ± (∆0 → γγ). Concerning (i), the reinterpretation of the recent supersymmetric tau partner search by ATLAS and CMS excludes m ∆ ± $$ {m}_{\Delta ^{\pm }} $$ < 110 GeV at 95% CL. From (ii), some of the signal regions of multi-lepton searches lead to bounds close to the predicted cross-section, but electroweak scale masses are still allowed. For (iii), the recast of the associated di-photon searches by ATLAS and a combined log-likelihood fit of signal and background to data find that out of the 25 signal regions, 10 provide relevant limits on Br(∆0 → γγ) at the per cent level. Interestingly, 6 signal regions show weaker than expected limits at around 152 GeV, leading to a preference for a non-zero di-photon branching ratio of about (0.7±0.2)%.
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spelling doaj-art-9029bb0f92ff40569bac36a62d8e1e272025-08-20T01:49:44ZengSpringerOpenJournal of High Energy Physics1029-84792025-04-012025415510.1007/JHEP04(2025)003Anatomy of the real Higgs triplet modelSaiyad Ashanujjaman0Sumit Banik1Guglielmo Coloretti2Andreas Crivellin3Siddharth P. Maharathy4Bruce Mellado5Institut für Theoretische Teilchenphysik, Karlsruhe Institute of TechnologyLaboratory for Particle Physics, PSI Center for Neutron and Muon SciencesLaboratory for Particle Physics, PSI Center for Neutron and Muon SciencesLaboratory for Particle Physics, PSI Center for Neutron and Muon SciencesSchool of Physics and Institute for Collider Particle Physics, University of the WitwatersrandSchool of Physics and Institute for Collider Particle Physics, University of the WitwatersrandAbstract In this article, we examine the Standard Model extended by a Y = 0 real Higgs triplet, the ∆SM. It contains a CP-even neutral Higgs (∆0) and two charged Higgs bosons (∆ ± ), which are quasi-degenerate in mass. We first study the theoretical constraints from vacuum stability and perturbative unitarity and then calculate the Higgs decays, including the loop-induced modes such as di-photons (γγ) and Zγ. In the limit of a small mixing between the SM Higgs and ∆0, the latter decays dominantly to WW and can have a sizable branching ratio to di-photon. The model predicts a positive definite shift in the W mass, which is compatible with the current global electroweak fit. At the Large Hadron Collider, it leads to a (i) stau-like signature from pp → ∆+∆ − → τ + τ − ν ν ¯ $$ {\tau}^{+}{\tau}^{-}\nu \overline{\nu} $$ , (ii) multi-lepton final states from pp → γ * → ∆+∆ − → W + W − ZZ and pp → W * → ∆ ± ∆0 → W ± ZW + W − as well as (iii) associated di-photon production from pp → W * → ∆ ± (∆0 → γγ). Concerning (i), the reinterpretation of the recent supersymmetric tau partner search by ATLAS and CMS excludes m ∆ ± $$ {m}_{\Delta ^{\pm }} $$ < 110 GeV at 95% CL. From (ii), some of the signal regions of multi-lepton searches lead to bounds close to the predicted cross-section, but electroweak scale masses are still allowed. For (iii), the recast of the associated di-photon searches by ATLAS and a combined log-likelihood fit of signal and background to data find that out of the 25 signal regions, 10 provide relevant limits on Br(∆0 → γγ) at the per cent level. Interestingly, 6 signal regions show weaker than expected limits at around 152 GeV, leading to a preference for a non-zero di-photon branching ratio of about (0.7±0.2)%.https://doi.org/10.1007/JHEP04(2025)003Higgs PropertiesMulti-Higgs ModelsNew Light ParticlesOther Weak Scale BSM Models
spellingShingle Saiyad Ashanujjaman
Sumit Banik
Guglielmo Coloretti
Andreas Crivellin
Siddharth P. Maharathy
Bruce Mellado
Anatomy of the real Higgs triplet model
Journal of High Energy Physics
Higgs Properties
Multi-Higgs Models
New Light Particles
Other Weak Scale BSM Models
title Anatomy of the real Higgs triplet model
title_full Anatomy of the real Higgs triplet model
title_fullStr Anatomy of the real Higgs triplet model
title_full_unstemmed Anatomy of the real Higgs triplet model
title_short Anatomy of the real Higgs triplet model
title_sort anatomy of the real higgs triplet model
topic Higgs Properties
Multi-Higgs Models
New Light Particles
Other Weak Scale BSM Models
url https://doi.org/10.1007/JHEP04(2025)003
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AT andreascrivellin anatomyoftherealhiggstripletmodel
AT siddharthpmaharathy anatomyoftherealhiggstripletmodel
AT brucemellado anatomyoftherealhiggstripletmodel