Lepton number violating operators with standard model gauge fields: a survey of neutrino masses from 3-loops and their link to dark matter

Gustafsson, M.; No, José Miguel; Rivera, Maximiliano A.

doi:10.1007/jhep11(2020)070

“…. [33,37,38] and more generally effective operators which violate lepton number by two units (∆L = 2) [39][40][41][42][43][44][45][46]. The last option allows for an efficient classification of a large number of models and their phenomenology associated with lepton-number violation.…”

Section: Jhep05(2021)122mentioning

confidence: 99%

The singly-charged scalar singlet as the origin of neutrino masses

Felkl

¹

,

Herrero-García

²

,

Schmidt

³

2021

J. High Energ. Phys.

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We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W-boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet. We also discuss the parameter space that can address the Cabibbo Angle Anomaly.

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“…Our goal in this work is to push this endeavor one step further by constructing a basis of dim-9 operators in SMEFT. Some small subsets of dim-9 operators have previously appeared in the literature focusing on processes of specific interest, including the operators related to Majorana neutrino mass and nuclear neutrinoless double beta decays (0νββ) [24][25][26][27], the operators contributing to neutron-antineutron (n −n) oscillation [28][29][30], and those relevant to rare nucleon decays [31][32][33]. This work provides the first systematic investigation on the basis of complete and independent dim-9 operators, and would serve as the starting point for further physical analysis.…”

Section: Jhep11(2020)152mentioning

confidence: 99%

“…As another example, ref. [27] recently studied the generation of neutrino mass through the operator O eeH 4 D 2 in the class…”

Section: Class ψ 2 ϕ 2 Dmentioning

confidence: 99%

An explicit construction of the dimension-9 operator basis in the standard model effective field theory

Liao

¹

,

Ma

²

2020

J. High Energ. Phys.

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We investigate systematically dimension-9 operators in the standard model effective field theory which contains only standard model fields and respects its gauge symmetry. With the help of the Hilbert series approach to classifying operators according to their lepton and baryon numbers and their field contents, we construct the basis of operators explicitly. We remove redundant operators by employing various kinematic and algebraic relations including integration by parts, equations of motion, Schouten identities, Dirac matrix and Fierz identities, and Bianchi identities. We confirm counting of independent operators by analyzing their flavor symmetry relations. All operators violate lepton or baryon number or both, and are thus non-Hermitian. Including Hermitian conjugated operators there are $$ {\left.384\right|}_{\Delta B=0}^{\Delta L=\pm 2}+{\left.10\right|}_{\Delta B=\pm 2}^{\Delta L=0}+{\left.4\right|}_{\Delta B=\pm 1}^{\Delta L=\pm 3}+{\left.236\right|}_{\Delta B=\pm 1}^{\Delta L=\mp 1} $$ 384 Δ B = 0 Δ L = ± 2 + 10 Δ B = ± 2 Δ L = 0 + 4 Δ B = ± 1 Δ L = ± 3 + 236 Δ B = ± 1 Δ L = ∓ 1 operators without referring to fermion generations, and $$ {\left.44874\right|}_{\Delta B=0}^{\Delta L=\pm 2}+{\left.2862\right|}_{\Delta B=\pm 2}^{\Delta L=0}+{\left.486\right|}_{\Delta B=\pm 1}^{\Delta L=\pm 3}+{\left.42234\right|}_{\Delta B=\mp 1}^{\Delta L=\pm 1} $$ 44874 Δ B = 0 Δ L = ± 2 + 2862 Δ B = ± 2 Δ L = 0 + 486 Δ B = ± 1 Δ L = ± 3 + 42234 Δ B = ∓ 1 Δ L = ± 1 operators when three generations of fermions are referred to, where ∆L, ∆B denote the net lepton and baryon numbers of the operators. Our result provides a starting point for consistent phenomenological studies associated with dimension-9 operators.

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“…. [33,37,38] and more generally effective operators which violate lepton number by two units (∆L = 2) [39][40][41][42][43][44][45][46]. The last option allows for an efficient classification of a large number of models and their phenomenology associated with leptonnumber violation.…”

mentioning

confidence: 99%

The Singly-Charged Scalar Singlet as the Origin of Neutrino Masses

Felkl,

Herrero-Garcia,

Schmidt

2021

Preprint

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We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W -boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet.We also discuss the parameter space that can address the Cabibbo Angle Anomaly.

show abstract

Lepton number violating operators with standard model gauge fields: a survey of neutrino masses from 3-loops and their link to dark matter

Cited by 6 publications

References 99 publications

The singly-charged scalar singlet as the origin of neutrino masses

The singly-charged scalar singlet as the origin of neutrino masses

An explicit construction of the dimension-9 operator basis in the standard model effective field theory

The Singly-Charged Scalar Singlet as the Origin of Neutrino Masses

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