Flavourful Z
                            ′ models for 


                                    

R

K

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$$ {R}_{K^{\left(\ast \right)}} $$

King, Stephen F.

doi:10.1007/jhep08(2017)019

Cited by 64 publications

(61 citation statements)

References 40 publications

(41 reference statements)

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“…The final set of patterns allowed for λ dl is given by the three-columned matrices of (22). Applying (35) to λ…”

Section: Su (2) Analysis For the Scalar ∆3mentioning

confidence: 99%

“…[9] for a definition of these coefficients), are sufficient to explain observations. On the other hand, numerous model-specific explanations for some or all of the data have also been offered, including Z , flavour symmetric, leptoquark, composite-and multi-higgs approaches [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Some of these models, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Simplified models of flavourful leptoquarks

Varzielas

Talbert

2019

Eur. Phys. J. C

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We study the implications of single leptoquark extensions of the Standard Model (SM) under the assumption that their enhanced Yukawa sectors are invariant under global Abelian flavour symmetries already present in SM mass terms. Such symmetries, assumed to be the 'residual' subgroups of an ultra-violet flavour theory, have previously been considered in order to predict fermionic mixing angles. Here we focus instead on their effect on the novel flavour structures sourced by the leptoquark representations that address the present R K ( ) anomalies in semileptonic rare B-decays. Combined with existing flavour data, the residual symmetries prove to be extremely constraining; we find that the (quark-lepton) leptoquark Yukawa couplings fall within O(10) highly predictive patterns, each with only a single free parameter, when 'normal' (SM-like) hierarchies are assumed. In addition, proton decay for the scalar SU(2) triplet representation is naturally avoided in the residual symmetry approach without relying on further model building. Our results indicate that a simultaneous explanation for the R K ( ) anomalies and the flavour puzzle may be achieved in a simplified, model-independent formalism.

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“…The final set of patterns allowed for λ dl is given by the three-columned matrices of (22). Applying (35) to λ…”

Section: Su (2) Analysis For the Scalar ∆3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simplified models of flavourful leptoquarks

Varzielas

Talbert

2019

Eur. Phys. J. C

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“…Here we identify the two righthanded neutrinos as originating from a fourth vector-like family, whose presence also allows for the generation of effective Yukawa couplings. Notice that the vector-like structure makes the model anomaly-free since the anomalies cancel between conjugate representations in the fourth family [27].…”

Section: Renormalisable Type Ib (Plus Type Ia) Seesaw Modelmentioning

confidence: 99%

“…In order to do this we identify the two right-handed neutrinos as originating from a fourth vector-like family, whose presence also allows for the generation of effective Yukawa couplings. The presence of a Z and a fourth vector-like family allows a connection between the observed hints for anomalous semi-leptonic B decays [25,26] which imply universality violation in the ratio R K ( * ) and the origin of the Yukawa couplings [27][28][29]. However we shall not pursue such a connection here.…”

Section: Introductionmentioning

confidence: 99%

New Weinberg operator for neutrino mass and its seesaw origin

Hernández-García

King

2019

J. High Energ. Phys.

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We consider a new Weinberg operator for neutrino mass of the form H uHd L i L j involving two different Higgs doublets H u , H d with opposite hypercharge, whereH d is the charge conjugated doublet. It may arise from a model where the two Higgs doublets carry the same charge under a U (1) gauge group which forbids the usual Weinberg operator but allows the mixed one. The new Weinberg operator may be generated via two right-handed neutrinos oppositely charged under the U (1) , which may be identified as components of a fourth vector-like family in a complete model. Such a version of the type I seesaw model, which we refer to as type Ib to distinguish it from the usual type Ia seesaw mechanism which yields the usual Weinberg operator, allows the possibility of having potentially large violations of unitarity of the leptonic mixing matrix whose bounds we explore. We also consider the relaxation of the unitarity bounds due to the further addition of a single right-handed neutrino, neutral under U (1) , yielding a usual type Ia seesaw contribution. * josu.hernandez@ts.infn.it † S.F.King@soton.ac.uk 1 arXiv:1903.01474v2 [hep-ph]

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“…From the amount of LUV alluded to in B → K ( * ) ± ∓ , one may expect B → K ( * ) LFV rates of the order of 10 −8 using general effective-theory (EFT) arguments [52]. More quantitative estimates require the introduction of a flavour model [45,[53][54][55][56][57][58][59][60][61][62][63][64]. As discussed in Ref.…”

Section: Tests Of Lfvmentioning

confidence: 99%