Model for the singlet-triplet leptoquarks

Rold, Leandro Da; Lamagna, Federico

doi:10.1103/physrevd.103.115007

Cited by 16 publications

(2 citation statements)

References 81 publications

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“…The models that contain leptoquarks have been discussed in some previous literature, e.g. [83][84][85][86][87][88][89][90][91][92][93]. Here, we consider the cases that can generate neutrino mass through the one-loop level JHEP05(2024)252 with the internal scalar particles as leptoquarks.…”

Section: One-loop Models With Leptoquarksmentioning

confidence: 99%

Neutrinoless double beta decay in multiple isotopes for fingerprints identification of operators and models

Chen,

Xiao

2024

J. High Energ. Phys.

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Neutrinoless double beta (0νββ) decay is the most promising way to determine whether neutrinos are Majorana particles. There are many experiments based on different isotopes searching for 0νββ decay. Combining the searches of 0νββ decay in multiple isotopes provides a possible method to distinguish operators and different models. The contributions to 0νββ decay come from standard, long-range, and short-range mechanisms. We analyze the scenario in which the standard and short-range operators exist simultaneously within the framework of low-energy effective field theory. Five specific models are considered, which can realize neutrino mass and can contribute to 0νββ decay via multiple mechanisms. A criterion to evaluate the possibilities of future experiments to discriminate operators and models is built. We find that the complementary searches for 0νββ decay in different isotopes can distinguish the cases that contain the low-energy effective operators $$ {\mathcal{O}}_{1,2,5} $$ O 1 , 2 , 5 and R-parity violating supersymmetry model. For other cases and models, the experimental searches within multiple isotopes can also more effectively constrain the parameter region than with only one isotope.

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Section: One-loop Models With Leptoquarksmentioning

confidence: 99%

Neutrinoless double beta decay in multiple isotopes for fingerprints identification of operators and models

Chen,

Xiao

2024

J. High Energ. Phys.

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“…Besides, as well-known, it provides a possible explanation of a µ and b → cτ ν data: it can account for the former by an m t /m µ -enhanced contribution [47, and enters b → cτ ν processes at tree level [58,62,75,[84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101] where it gives a very good fit to data (including polarization observables) [28,[102][103][104] since it generates vector, scalar and tensor operators. Finally, slight extensions of the model also allow for a combined explanation of b → cτ ν and b → s + − data [75,83,93,[105][106][107][108]. In particular, the singlet-triplet LQ model [93], containing S 1 and S 3 can account for all three anomalies [75,106] and we will return to this model at end of our analysis.…”

Section: Introductionmentioning

confidence: 99%

Forward-backward asymmetry in B→D*ℓν : One more hint for scalar leptoquarks?

et al. 2022

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In recent years, intriguing hints for the violation of lepton flavour universality have accumulated.In particular, deviations from the Standard-Model (SM) predictions in B → D ( * ) τ ν/B → D ( * ) ν, in the anomalous magnetic moment of the muon and in b → s + − data were observed with a significance of > 3 σ, > 4 σ and > 5 σ, respectively. Furthermore, in a recent re-analysis of 2018 Belle data, it was found that the forward-backward asymmetry of B → D * µν vs B → D * eν disagrees with the SM prediction by ≈4 σ which would be an additional sign of lepton flavour universality violation. Since one naturally expects muon-related new effects to also emerge at some point in b → cµν decays, the above putative deviation might share a common origin with the other flavour anomalies. We show that a tensor operator is necessary to significantly improve the global fit w.r.t. the SM, which can only be induced (at tree-level in a renormalizable model) by a scalar leptoquark. Interestingly, among the two possible representations, the SU (2)L-singlet S1 and the doublet S2, which can both also account for the anomalous magnetic moment of the muon, only S1 can provide a good fit as it gives rise to the scenario CV L, CSL = −4CT . While the constraints from (differences of) other angular observables prefer a smaller value of ∆AFB than the current central one, this scenario is significantly preferred (≈ 3σ) over the SM hypothesis, and compatible with constraints such as B → K * νν and electroweak precision bounds.

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

Crivellin

Eguren

Virto

2022

J. High Energ. Phys.

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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.

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Model for the singlet-triplet leptoquarks

Cited by 16 publications

References 81 publications

Neutrinoless double beta decay in multiple isotopes for fingerprints identification of operators and models

Neutrinoless double beta decay in multiple isotopes for fingerprints identification of operators and models

Forward-backward asymmetry in B→D*ℓν : One more hint for scalar leptoquarks?

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

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