Revisiting Type-II see-saw: Present Limits and Future Prospects at LHC

Ashanujjaman, Saiyad; Ghosh, Kirtiman

doi:10.48550/arxiv.2108.10952

Cited by 5 publications

(7 citation statements)

References 95 publications

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“…The gauge interactions of H ± and H ±± with the SM photon, W and Z bosons in table 1 are relevant for the pair production H ++ H −− and the associated production H ±± H ∓ of the doubly-charged scalar at hadron colliders, as in the Type-II seesaw case [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. The remaining couplings in table 1 are relevant to the decays of H ± and H ±± .…”

Section: Key Parameters and Decay Channels Of H ±± And H ±mentioning

confidence: 99%

Leptonic scalars and collider signatures in a UV-complete model

Dev¹,

Dutta

Ghosh

et al. 2022

J. High Energ. Phys.

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We study the non-standard interactions of neutrinos with light leptonic scalars (ϕ) in a global (B − L)-conserved ultraviolet (UV)-complete model. The model utilizes Type-II seesaw motivated neutrino interactions with an SU(2)L-triplet scalar, along with an additional singlet in the scalar sector. This UV-completion leads to an enriched spectrum and consequently new observable signatures. We examine the low-energy lepton flavor violation constraints, as well as the perturbativity and unitarity constraints on the model parameters. Then we lay out a search strategy for the unique signature of the model resulting from the leptonic scalars at the hadron colliders via the processes H±±→ W±W±ϕ and H±→ W±ϕ for both small and large leptonic Yukawa coupling cases. We find that via these associated production processes at the HL-LHC, the prospects of doubly-charged scalar H±± can reach up to 800 (500) GeV and 1.1 (0.8) TeV at the 2σ (5σ) significance for small and large Yukawa couplings, respectively. A future 100 TeV hadron collider will further increase the mass reaches up to 3.8 (2.6) TeV and 4 (2.7) TeV, at the 2σ (5σ) significance, respectively. We also demonstrate that the mass of ϕ can be determined at about 10% accuracy at the LHC for the large Yukawa coupling case even though it escapes as missing energy from the detectors.

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Section: Key Parameters and Decay Channels Of H ±± And H ±mentioning

confidence: 99%

Leptonic scalars and collider signatures in a UV-complete model

Dev¹,

Dutta

Ghosh

et al. 2022

J. High Energ. Phys.

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“…Let us now turn our attention to the singly-charged scalar, H ± , starting with all the relevant partial decay widths, for the case δm = 0. They are given as [48][49][50][51][52][53]:…”

Section: The Singly Charged Scalarmentioning

confidence: 99%

“…In order to do that let us first discuss all the relevant H 0 /A partial decay widths. Assuming δm = 0 we have that the H 0 decay widths are given as [48][49][50][51][52][53]: where tan(2α) = 2B A−C , N f c is the color factor with N q c = 3 and N c = 1, κ = 2(1) for i = j(i = j). For nonzero mass splitting, in this case one must have δm < 0, and the relevant CP-even decay width is…”

Section: The Neutral Scalarsmentioning

confidence: 99%

Towards deconstructing the simplest seesaw mechanism

Mandal,

Miranda,

Garcia

et al. 2022

Preprint

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The triplet or type-II seesaw mechanism is the simplest way to endow neutrinos with mass in the Standard Model (SM). Here we review its associated theory and phenomenology, including restrictions from S, T , U parameters, neutrino experiments, charged lepton flavour violation as well as collider searches. We also examine restrictions coming from requiring consistency of electroweak symmetry breaking, i.e. perturbative unitarity and stability of the vacuum. Finally, we discuss novel effects associated to the scalar mediator of neutrino mass generation namely, (i) rare processes, e.g. lα → l β γ decays, at the intensity frontier, and also (ii) four-lepton signatures in colliders at the highenergy frontier. These can be used to probe neutrino properties in an important way, providing a test of the absolute neutrino mass and mass-ordering, as well as of the atmospheric octant. They may also provide the first evidence for charged lepton flavour violation in nature. In contrast, neutrino non-standard interaction strengths are found to lie below current detectability.

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“…The decay widths for other new scalars are shown in Ref. [156,157]. For Y = 0 case, the potential parameters can be expressed in terms of physical Higgs mass and mixing angle θ as well as v Σ via the help of Eqs.…”

Section: Production and Detection For Doubly Charged Higgs In The Lep...mentioning

confidence: 99%

Electroweak precision tests for triplet scalars

Yu¹,

He²,

Huang³

et al. 2022

Preprint

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Electroweak precision observables are fundamentally important for testing the standard model (SM) or its extensions. The influences to observables from new physics within the electroweak sector can be expressed in terms of oblique parameters S, T, U. The recently reported W mass excess anomaly by CDF modifies these parameters in a significant way. By performing the global fit with the CDF new W mass measurement data, we obtain S = 0.03 ± 0.03, T = 0.06 ± 0.02 and U = 0.16 ± 0.03 (or S = 0.14 ± 0.03, T = 0.24 ± 0.02 with U = 0) which is significantly away from zero as SM would predict. The CDF excess strongly indicates the need of new physics beyond SM. We carry out a global fit to study the influence of two different cases of simple extensions by a hyper-charge Y = 1 triplet scalar ∆ (corresponding to the type-II seesaw model) and a Y = 0 real triplet scalar Σ on electroweak precision tests to determine parameter space in these models to solve the W mass anomaly and discuss the implications. We find that these triplets can affect the oblique parameters significantly at the tree and loop levels. For Y = 1 case, there are seven new scalars in the model. The tree and scalar loop effects on oblique parameters can be expressed in terms of three parameters, the neutral CP-even mass mH , potential parameter λ4 and triplet vev v∆. Our global fit obtains mH = 296.02 ± 10.18 GeV, λ4 = 2.58 ± 0.09 and v∆ = 4.82 ± 0.34 GeV. These parameter correspondingly results in mass difference ∆m 2 = (197.49 ± 3.45GeV) 2 . Using these fit values, we further obtain m H ++ = 98.09 ± 20.02GeV, which satisfies the current LHC constraints. We also further adopt the phenomenological analysis, such as vacuum stability and perturbative unitarity, Higgs data and triple Higgs self-coupling. Furthermore, we find that the future lepton colliders can feasibly search for doubly charged H ++ via pair production H ++ H −− and decay channel to four W final states. For Y = 0 case, there are four new scalars in the model. The tree and new scalar effects on the oblique parameters can be parameterized by the singly charged mass m H + , the mass difference ∆m = m H + − m H 0 and triplet vev vΣ. Our global fit obtains m H + = 77.16 ± 17.12 GeV, ∆m = −14.27 ± 4.22 GeV and vΣ = 3.20 ± 0.30 GeV. However, these strongly violate the perturbative unitarity of the potential parameter b4, which can only be satisfied within 3σ errors.

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Revisiting Type-II see-saw: Present Limits and Future Prospects at LHC

Cited by 5 publications

References 95 publications

Leptonic scalars and collider signatures in a UV-complete model

Leptonic scalars and collider signatures in a UV-complete model

Towards deconstructing the simplest seesaw mechanism

Electroweak precision tests for triplet scalars

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