Charged lepton flavor violating decays: leading logarithmic approximation versus full RG results

Petcov, S.T.; Profumo, Stefano; Takanishi, Yasutaka; Yaguna, Carlos E.

doi:10.1016/j.nuclphysb.2003.10.020

Cited by 94 publications

(94 citation statements)

References 54 publications

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“…1 The exact one-loop renormalization group equations may give somewhat different results as pointed out in [11] and studied in more detail for lepton-flavor violating processes of interest in a forthcoming article [12]. For consistency with the results on radiative decays, derived in [7] and used in the present analysis, we restrict ourselves here to the approximation (12)- (14).…”

Section: Renormalization Group Evolution Of the Slepton Massesmentioning

confidence: 96%

Supersymmetric seesaw model and lepton-flavor violation at a future electron-positron linear collider

et al. 2004

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We study lepton-flavor violating slepton production and decay at a future e + e − linear collider in context with the seesaw mechanism in mSUGRA post-LEP benchmark scenarios. The present knowledge in the neutrino sector as well as improved future measurements are taken into account. We calculate the signal cross-sections σ(e ± e − → l ± β l − αχ 0 bχ 0 a ); l δ = e, µ, τ ; α = β and estimate the main background processes. Furthermore, we investigate the correlations of these signals with the corresponding lepton-flavor violating rare decays l α → l β γ. It is shown that these correlations are relatively weakly affected by uncertainties in the neutrino data, but very sensitive to the model parameters. Hence, they are particularly suited for probing the origin of

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Section: Renormalization Group Evolution Of the Slepton Massesmentioning

confidence: 96%

Supersymmetric seesaw model and lepton-flavor violation at a future electron-positron linear collider

et al. 2004

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“…In the "mass insertion" and leading-log approximations (see, e.g., [22,24,28]), the branching ratio of l i → l j + γ decay due to the new contributions has the following form…”

Section: The Lfv Decaysmentioning

confidence: 99%

“…It was shown in [28] that in most of the relevant soft SUSY breaking parameter space, the expression…”

Section: The Lfv Decaysmentioning

confidence: 99%

“…If the SUSY breaking occurs via soft terms with universal boundary conditions at a scale M X above the RH Majorana neutrino mass scale M R , M X > M R 2 , the renormalisation group (RG) effects transmit the LFV from the neutrino mixing at M X to the effective mass terms of the scalar leptons at M R even if the soft SUSY breaking terms at M X are flavour symmetric and conserve the lepton charges L l . As a consequence of these RG-induced new LFV terms in the effective Lagrangian at M R < M X , the LFV processes can proceed with rates and cross sections which are within the sensitivity of presently operating and future planned experiments [20,22] (see also, e.g., [23,24,25,26,27,28,29,30]). In contrast, in the non-supersymmetric case, the rates and cross sections of the LFV processes are suppressed by the factor [31] (see also [32]) (m j /M W ) 4 < 6.7 × 10 −43 , M W being the W ± mass, which renders them unobservable.…”

Section: Introductionmentioning

confidence: 99%

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The see-saw mechanism, neutrino Yukawa couplings, LFV decays li→lj+γ and leptogenesis

et al. 2006

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The LFV charged lepton decays µ → e+γ, τ → e+γ and τ → µ+γ and thermal leptogenesis are analysed in the MSSM with see-saw mechanism of neutrino mass generation and soft SUSY breaking with universal boundary conditions. The case of hierarchical heavy Majorana neutrino mass spectrum, M 1 ≪ M 2 ≪ M 3 , is investigated. Leptogenesis requires M 1 > ∼ 10 9 GeV. Considering the natural range of values of the heaviest right-handed Majorana neutrino mass, M 3 > ∼ 5 × 10 13 GeV, and assuming that the soft SUSY breaking universal gaugino and/or scalar masses have values in the range of few × 100 GeV, we derive the combined constraints, which the existing stringent upper limit on the µ → e + γ decay rate and the requirement of successful thermal leptogenesis impose on the neutrino Yukawa couplings, heavy Majorana neutrino masses and SUSY parameters. Results for the three possible types of light neutrino mass spectrumnormal and inverted hierarchical and quasi-degenerate -are obtained.

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“…Here we have set θ 13 = 0 • computation by a factor of three. In general, the divergence of the LLog and the full computation occurs for low M 0 and large M 1/2 [22,23] and/or large A 0 values [2]. The failure of the LLog is more dramatic for SUSY scenarios with large A 0 .…”

Section: Results For Hierachical Heavy Neutrinosmentioning

confidence: 95%

LFV in tau and muon decays within SUSY seesaw

Antusch

Arganda

Herrero

et al. 2007

Nuclear Physics B - Proceedings Supplements

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In these proceedings we present the results for lepton flavour violating tau and muon decays within the SUSY seesaw scenario. Specifically, we consider the Constrained Minimal Supersymmetric Standard Model extended by three right handed neutrinos, νR i and their corresponding SUSY partners,νR i , (i = 1, 2, 3), and use the seesaw mechanism for neutrino mass generation. We include the predictions for the branching ratios of two types of lepton flavour violating channels, lj → liγ and lj → 3li, and compare them with the present bounds and future experimental sensitivities. We first analyse the dependence of the branching ratios with the most relevant SUSY seesaw parameters, and we then focus on the particular sensitivity to θ13, which we find specially interesting on the light of its potential future measurement. We further study the constraints from the requirement of successfully producing the baryon asymmetry of the Universe via thermal leptogenesis, which is another appealing feature of the SUSY seesaw scenario. We conclude with the impact that a potential measurement of θ13 can have on lepton flavour violating physics. This is a very short summary of the works in Refs.[1] and [2] to which we refer the reader for more details. LFV within SUSY seesawThe seesaw mechanism is implemented by the inclusion of a Majorana mass m R for the right handed neutrinos (allowed due to their singlet character under all the symmetries of the Standard Model (SM)) and by considering a large separation between this mass and the electroweak (EW) scale [3]. After EW symmetry breaking, the full 6 × 6 neutrino mass matrix is given in terms of the 3 × 3 Dirac mass matrix, that we work in a lepton basis where both the right handed mass matrix and the charged lepton mass matrix are diagonal in flavour space. The flavour mixing in the light neutrino sector is given by the Maki-Nakagawa-Sakata matrix U MNS [4] for which we use the standard parameterization, which is written in terms of three mixing angles θ 12 , θ 13 and θ 23 and three CP violating phases δ, ϕ 1 and ϕ 2 .We use here the parameterisation proposed in Ref. [5], where the solution to the seesaw equation, with R being a 3 × 3 orthogonal complex matrix, defined by three complex angles θ i (i = 1, 2, 3). The attractiveness of this parameterisation is that it allows to easily implement the requirement of compatibility with low energy neutrino data. It also clearly shows that in the singlet seesaw scenario one can have large neutrino Yukawa couplings, Y ν ∼ O(1), by simply choosing large entries in m diag N . The main implication of these large Yukawa coupling is that they can induce large lepton flavour violating (LFV) rates [6]. The total number of parameters of the neutrino sector in this scenario is 18, which in this particular pa-1

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Charged lepton flavor violating decays: leading logarithmic approximation versus full RG results

Cited by 94 publications

References 54 publications

Supersymmetric seesaw model and lepton-flavor violation at a future electron-positron linear collider

Supersymmetric seesaw model and lepton-flavor violation at a future electron-positron linear collider

The see-saw mechanism, neutrino Yukawa couplings, LFV decays li→lj+γ and leptogenesis

LFV in tau and muon decays within SUSY seesaw

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