μ-e conversion in nuclei and Z′ physics

Bernabéu, J.; Nardi, Enrico; Tommasini, D.

doi:10.1016/0550-3213(93)90446-v

Cited by 125 publications

(116 citation statements)

References 34 publications

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“…[103,106] (see also [107][108][109] for detailed works regarding the effective lagrangian at the nucleon level, [68,110] for a calculation including the effects of the atomic electric field and [111] for recent improvements on the hadronic uncertainties). The conversion rate, relative to the the muon capture rate, can be expressed as…”

Section: Coherent µ − E Conversion In Nucleimentioning

confidence: 99%

Lepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions

Abada

Krauss

Porod

et al. 2014

J. High Energ. Phys.

110

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Taking the supersymmetric inverse seesaw mechanism as the explanation for neutrino oscillation data, we investigate charged lepton flavor violation in radiative and 3-body lepton decays as well as in neutrinoless µ − e conversion in muonic atoms. In contrast to former studies, we take into account all possible contributions: supersymmetric as well as non-supersymmetric. We take CMSSM-like boundary conditions for the soft supersymmetry breaking parameters. We find several regions where cancellations between various contributions exist, reducing the lepton flavor violating rates by an order of magnitude compared to the case where only the dominant contribution is taken into account. This is in particular important for the correct interpretation of existing data as well as for estimating the reach of near future experiments where the sensitivity will be improved by one to two orders of magnitude. Moreover, we demonstrate that ratios like BR(τ → 3µ)/BR(τ → µe + e − ) can be used to determine whether the supersymmetric contributions dominate over the W ± and H ± contributions or vice versa.

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Section: Coherent µ − E Conversion In Nucleimentioning

confidence: 99%

Lepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions

Abada

Krauss

Porod

et al. 2014

J. High Energ. Phys.

110

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“…Here, Z represents the proton number of the nucleus X; Z eff and F (q) are the effective charge and the nuclear form factor at the momentum transfer q, respectively. In the case of X = 48 22 Ti, for which Z = 22, Z eff ≃ 17.6 and |F (q)| ≃ 0.54 [40], we obtain the prediction for the µ → e conversion rate, normalized by the muon capture rate Γ(µ → capture; …”

Section: Other Lepton Flavor Violating Processesmentioning

confidence: 99%

Complete theory of grand unification in five dimensions

2002

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A fully realistic unified theory is constructed, with SU (5) gauge symmetry and supersymmetry both broken by boundary conditions in a fifth dimension. Despite the resulting explicit breaking of SU (5) locally at a boundary of the dimension, when the size of the extra dimension is taken to be large precise predictions emerge for gauge coupling unification, α s (M Z ) = 0.118 ± 0.003, and for Yukawa coupling unification, m b (M Z ) = 3.3 ± 0.2 GeV. The 5D theory is then valid over a large energy interval from the compactification scale, M c ≃ 1×10 15 GeV, to the scale of strong coupling, M s ≃ 1×10 17 GeV. A complete understanding of the Higgs sector of the minimal supersymmetric standard model is given; with explanations for why the Higgs triplets are heavy, why the Higgs doublets are protected from a large tree-level mass, and why the µ and B parameters are naturally generated to be of order the supersymmetry breaking scale. All sources of proton decay from operators of dimension four and five are forbidden, while a new origin for baryon number violating dimension six operators is found to be important. The exchange of the superheavy gauge boson, with a brane-localized kinetic energy interaction, leads to τ p ≈ 10 34 years, with several branching ratios determined in terms of a single mixing parameter. The theory is only realistic for an essentially unique choice of matter location in the fifth dimension: the ten-plets of the first two generations must lie in the bulk, with all other matter located on the SU (5) preserving boundary. Several aspects of flavor follow from this geometry: only the third generation possesses an SU (5) mass relation, and the lighter two generations have only small mixings with the heaviest generation except for neutrinos. The entire superpartner spectrum is predicted in terms of only two free parameters. The squark and slepton masses have sizes determined by their location in the fifth dimension, allowing a significant experimental test of the detailed structure of the extra dimension. Lepton flavor violation is found to be generically large in higher dimensional unified theories with non-trivial matter geometries, providing soft supersymmetry breaking operators are local up to the compactification scale. In our theory this forces a common location for all three neutrinos, predicting large neutrino mixing angles. Rates for µ → eγ, µ → eee, µ → e conversion and τ → µγ are larger in our theory than in conventional 4D supersymmetric grand unified theories, and, once superpartner masses are measured, these rates are completely determined in terms of two leptonic mixing angles. Proposed experiments probing µ → e transitions will probe the entire interesting parameter space of our theory.

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“…Muon conversion on a nucleus [2,[12][13][14][15][16][17] offers a sensitive probe of new physics and a nice possibility to study it experimentally providing an interesting interplay of particle and nuclear physics effects. The number of relevant operators in Eqs.…”

Section: Constraints From µ-E Conversionmentioning

confidence: 99%

Lepton flavor-violating transitions in effective field theory and gluonic operators

Petrov

Zhuridov

2014

Phys. Rev. D

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Lepton flavor-violating processes offer interesting possibilities to probe new physics at multi-TeV scale. We discuss those in the framework of effective field theory, emphasizing the role of gluonic operators. Those operators are obtained by integrating out heavy quarks that are kinematically inaccessible at the scale where low-energy experiments take place and make those experiments sensitive to the couplings of lepton flavor changing neutral currents to heavy quarks. We discuss constraints on the Wilson coefficients of those operators from the muon conversion µ − + (A, Z) → e − + (A, Z) and from lepton flavor-violating tau decays with one or two hadrons in the final state, e.g. τ → ℓ η (′) and τ → ℓ π + π − with ℓ = µ, e. To illustrate the results we discuss explicit examples of constraining parameters of leptoquark models.

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μ-e conversion in nuclei and Z′ physics

Cited by 125 publications

References 34 publications

Lepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions

Lepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions

Complete theory of grand unification in five dimensions

Lepton flavor-violating transitions in effective field theory and gluonic operators

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