Static weak dipole moments of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math>lepton via renormalizable scalar leptoquark interactions

Bolaños, A.; Moyotl, A.; Tavares‐Velasco, G.

doi:10.1103/physrevd.89.055025

Cited by 15 publications

(16 citation statements)

References 61 publications

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“…(15) after the proper replacements are made. The result is in agreement with previous calculations of the i → j γ decay width [38].…”

Section: Decay τ → μγsupporting

confidence: 93%

“…The former one is a non-chiral LQ that couples to up quarks and charged leptons, thereby giving rise to FCNC top quark and Higgs boson decays at the one-loop level, but also to the t → c¯ decay at the tree-level. The phenomenology of this model was studied in [17] and bounds on its couplings to a leptonquark pairs from the experimental constraints on the muon anomalous magnetic dipole moment and the LFV tau decay τ → μγ were obtained in [38]. We first start by discussing the corresponding LQ couplings to quarks and leptons and afterwards we discuss the remaining interactions.…”

Section: A Simple Scalar Lq Modelmentioning

confidence: 99%

“…The phenomenology of the scalar LQ doublet R 2 has been long studied in the literature [17,18,38,[42][43][44], and constraints on their mass and couplings have been derived from the Z → bb decay, the muon anomalous MDM, and LFV decays. Since low energy physics strongly constrains the LQ couplings to the first-generation fermions, it is usually assumed that the only non-negligible couplings are those to the fermions of the second and third generations.…”

Section: Constraints On Scalar Lq Massesmentioning

confidence: 99%

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Flavor changing neutral current decays $$t\rightarrow c X$$ ($$X=\gamma ,\,g,\, Z,\, H$$) and $$t\rightarrow c{{\bar{\ell }}}\ell $$ ($$\ell =\mu ,\,\tau $$) via scalar leptoquarks

2019

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The flavor changing neutral current decays t → cX (X = γ, g, Z , H) and t → c¯ (= μ, τ) are studied in a renormalizable scalar leptoquark (LQ) model with no proton decay, where a scalar SU (2) doublet with hypercharge Y = 7/6 is added to the standard model, yielding a non-chiral LQ Ω 5/3. Analytical results for the one-loop (tree-level) contributions of a scalar LQ to the f i → f j X (f i → f jfm f l) decays, with f a = q a , a , are presented. We consider the scenario where Ω 5/3 couples to the fermions of the second and third families, with its right-and left-handed couplings obeying λ u i R /λ u i L = O(), where parametrizes the relative size between these couplings. The allowed parameter space is then found via the current constraints on the muon (g − 2), the τ → μγ decay, the LHC Higgs boson data, and the direct LQ searches at the LHC. For m Ω 5/3 = 1 TeV and = 10 −3 , we find that the t → cX branching ratios are of similar size and can be as large as 10 −8 in a tiny area of the parameter space, whereas Br(t → cτ τ) [Br(t → cμμ)] can be up to 10 −6 (10 −7).

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“…(15) after the proper replacements are made. The result is in agreement with previous calculations of the i → j γ decay width [38].…”

Section: Decay τ → μγsupporting

confidence: 93%

Section: A Simple Scalar Lq Modelmentioning

confidence: 99%

Section: Constraints On Scalar Lq Massesmentioning

confidence: 99%

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Flavor changing neutral current decays $$t\rightarrow c X$$ ($$X=\gamma ,\,g,\, Z,\, H$$) and $$t\rightarrow c{{\bar{\ell }}}\ell $$ ($$\ell =\mu ,\,\tau $$) via scalar leptoquarks

2019

Self Cite

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“…To contextualize our results, we cite some predictions of a τ in some extended models. The estimations for a τ coming from two-Higgs doublet models [51], the minimal supersymmetric Standard Model [52], and the unparticle model [53] are of the order of 10 −6 , whereas for leptoquark models, a τ can be as high as 10 −8 [54], which coincides with the strongest prediction of the simplest little Higgs model [55].…”

Section: Cp Conservation: a τmentioning

confidence: 58%

Flavor violation in chromo- and electromagnetic dipole moments induced by Z′ gauge bosons and a brief revisit of the Standard Model

et al. 2018

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The electromagnetic dipole moments of the tau lepton and the chromoelectromagnetic dipole moments of the top quark are estimated via flavor-changing neutral currents, mediated by a new neutral massive gauge boson. We predict them in the context of models beyond the Standard Model with extended current sectors, in which simple analytic expressions for the dipole moments are presented. For the different Z 0 gauge boson considered, the best prediction for the magnetic dipole moment of the tau lepton, ja τ j, is of the order of 10 −8 , while the highest value for the electric one, jd τ j, corresponds to 10 −24 e cm; our main result for the chromomagnetic dipole moment of the top quark, jμ t j, is 10 −6 , and the value for the chromoelectric one, jd t j, can be as high as 10 −22 e cm. We compare our results, revisiting the corresponding Standard Model predictions, in which the chromomagnetic dipole moment of the top quark is carefully evaluated, finding explicit imaginary contributions.

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“…Ref. [70] includes a calculation of the contributions from scalar leptoquark interactions to the tau anomalous magnetic moment, with values between ∼ 10 −9 and ∼ 10 −8 .…”

Section: Anomalous Magnetic Momentsmentioning

confidence: 99%

Electric dipole moments of charged leptons at one loop in the presence of massive neutrinos

et al. 2017

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Violation of CP invariance is a quite relevant phenomenon that is found in the Standard Model, though in small amounts. This has been an incentive to look for high-energy descriptions in which CP violation is increased, thus enhancing effects that are suppressed in the Standard Model, such as the electric dipole moments of elementary particles. In the present investigation, we point out that charged currents in which axial couplings are different from vector couplings are able to produce one-loop contributions to electric dipole moments of charged leptons if neutrinos are massive and if these currents violate CP . We develop our discussion around charged currents involving heavy neutrinos and a W ′ gauge boson coupling to Standard Model charged leptons. Using the most stringent bound on the electron electric dipole moment, provided by the ACME Collaboration, we determine that the upper bound on the difference between axial and vector currents lies within ∼ 10 −10 and ∼ 10 −7 for heavy-neutrino masses between 0.5 TeV and 6 TeV and if the W ′ mass is within 0.45 TeV − 7 TeV. This possibility is analyzed altogether with the anomalous magnetic moments of charged leptons, among which we estimate, for the τ lepton, an anomalous magnetic moment contribution between ∼ 10 −8 and ∼ 10 −10 for neutrino masses ranging from 0.5 TeV to 6 TeV and a W ′ mass between 0.45 TeV and 7 TeV. The general charged currents are also used to calculate the branching ratio for µ → eγ, which gets suppressed if the set of masses of heavy neutrinos is quasidegenerate. In a scenario of nondegenerate neutrino masses, we find that regions of neutrino and W ′ masses in which the contributions to this flavor changing branching ratio are lower than the current upper bound exist. We show that such regions can be widened if the W ′ gauge boson mass is larger.

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Static weak dipole moments of theτlepton via renormalizable scalar leptoquark interactions

Cited by 15 publications

References 61 publications

Flavor changing neutral current decays $$t\rightarrow c X$$ ($$X=\gamma ,\,g,\, Z,\, H$$) and $$t\rightarrow c{{\bar{\ell }}}\ell $$ ($$\ell =\mu ,\,\tau $$) via scalar leptoquarks

Flavor changing neutral current decays $$t\rightarrow c X$$ ($$X=\gamma ,\,g,\, Z,\, H$$) and $$t\rightarrow c{{\bar{\ell }}}\ell $$ ($$\ell =\mu ,\,\tau $$) via scalar leptoquarks

Flavor violation in chromo- and electromagnetic dipole moments induced by Z′ gauge bosons and a brief revisit of the Standard Model

Electric dipole moments of charged leptons at one loop in the presence of massive neutrinos

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