Lepton Flavour Violation in Models with A4 Flavour Symmetry
| dc.creator | Feruglio, Ferruccio | |
| dc.creator | Hagedorn, Claudia | |
| dc.creator | Lin, Yin | |
| dc.creator | Merlo, Luca | |
| dc.date | 2008-07-20 | |
| dc.date.accessioned | 2026-07-07T12:15:03Z | |
| dc.date.available | 2026-07-07T12:15:03Z | |
| dc.description | We analyze lepton flavour violating transitions, leptonic magnetic dipole moments (MDMs) and electric dipole moments (EDMs) in a class of models characterized by the flavour symmetry A4 x Z3 x U(1)_{FN}, whose choice is motivated by the approximate tri-bimaximal mixing observed in neutrino oscillations. We construct the relevant low-energy effective Lagrangian where these effects are dominated by dimension six operators, suppressed by the scale M of new physics. All the flavour breaking effects are universally described by the vacuum expectation values <Phi> of a set of spurions. We separately analyze both a supersymmetric and a general case. While the observed discrepancy delta a_mu in the anomalous MDM of the muon suggests M of order of a few TeV, several data require M above 10 TeV, in particular the limit on EDM of the electron. In the general case also the present limit on BR(mu -> e gamma) requires M >10 TeV, at least. The branching ratios for mu -> e gamma, tau -> mu gamma and tau -> e gamma are all expected to be of the same order. In the supersymmetric case the constraint from mu -> e gamma is softened and it can be satisfied by a smaller scale M. In this case both the observed delta a_mu and the current bound on BR(mu -> e gamma) can be satisfied, at the price of a rather small value for |<Phi>|, of the order of a few percents, that reflects on a similar value for theta_{13}. | |
| dc.description | 29 pages, 1 figure | |
| dc.identifier | https://arxiv.org/abs/0807.3160 | |
| dc.identifier | http://arxiv.org/abs/0807.3160 | |
| dc.identifier | Nucl.Phys.B809:218-243,2009 | |
| dc.identifier | doi:10.1016/j.nuclphysb.2008.10.002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/211397 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Lepton Flavour Violation in Models with A4 Flavour Symmetry | |
| dc.type | text |