Searching for lepton flavor universality violation and collider signals from a singly charged scalar singlet

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.

Section: Jhep05(2021)122mentioning

confidence: 93%

Section: Jhep05(2021)122mentioning

confidence: 99%

Section: Effective Description Of Low-energy Phenomenology At Tree Levelmentioning

confidence: 99%

Section: Jhep05(2021)122mentioning

confidence: 99%

Section: Jhep05(2021)122mentioning

confidence: 99%

See 3 more Smart Citations

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

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Herrero-García

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et al. 2022

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Next-to-leading-order QCD matching for ∆F = 2 processes in scalar leptoquark models

Crivellin

Eguren

Virto

2022

Leptoquarks provide viable solutions to the flavour anomalies, i.e. they can explain the tensions between the measurements and the Standard Model predictions of the anomalous magnetic moment of the muon as well as b → sℓ+ℓ− and b → cτν processes. However, LQs also contribute to other flavour observables, such as ∆F = 2 processes, at the loop-level. In particular, Bs−$$ \overline{B} $$ B ¯ s mixing provides a crucial bound in setups addressing b → cτν data, often excluding a big portion of the parameter space that could otherwise account for it. In this article, we first derive the complete leading order matching, including all five scalar LQ representations, for D0−$$ \overline{D} $$ D ¯ 0, K0−$$ \overline{K} $$ K ¯ 0 and Bs,d−$$ \overline{B} $$ B ¯ s,d mixing (at the dimension-six level). We then calculate the next-to-leading order αs matching corrections to these ∆F = 2 processes in generic scalar leptoquark models. We find that the two-loop corrections increase the effects in ∆F = 2 processes by ~ 5-10% and significantly reduce the matching scale uncertainty.