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Related papers: Effective approach to lepton observables: the sees…

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Lepton flavor violating processes are optimal observables to test new physics, since they are forbidden in the Standard Model while they may be generated in new theories. The usual approach to these processes is to perform the computations…

High Energy Physics - Phenomenology · Physics 2020-02-18 Xabier Marcano , Roberto A. Morales

In this paper we study the Lepton Flavor Violating $Z$ boson decays $Z \to \tau \mu$ and $Z \to \tau e$ in the context of low scale seesaw models with new heavy Majorana neutrinos whose masses could be reachable at the LHC. Our computations…

High Energy Physics - Phenomenology · Physics 2017-04-26 V. De Romeri , M. J. Herrero , X. Marcano , F. Scarcella

We discuss in detail the constraints on partial compositeness coming from flavour and CP violation in the leptonic sector. In a first part we present a formulation of partial compositeness in terms of a flavour symmetry group and a set of…

High Energy Physics - Phenomenology · Physics 2016-01-27 Ferruccio Feruglio , Paride Paradisi , Andrea Pattori

Following recent experimental developments, in this study we re-evaluate if the interplay of high- and low-energy lepton flavour violating observables remains a viable probe to test the high-scale type-I supersymmetric seesaw. Our analysis…

High Energy Physics - Phenomenology · Physics 2015-03-03 A. J. R. Figueiredo , A. M. Teixeira

We study the impact of a type-I SUSY seesaw concerning lepton flavour violation (LFV) at low-energies and at the LHC. At the LHC, $ \chi_2^0\to \tilde \ell \,\ell \to \ell \,\ell\,\chi_1^0$ decays, in combination with other observables,…

High Energy Physics - Phenomenology · Physics 2015-03-03 A. M. Teixeira , A. Abada , A. J. R. Figueiredo , J. C. Romao

We compile information from low-energy observables sensitive to flavor-conserving 4-fermion operators with two or four leptons. Our analysis includes data from e+e- colliders, neutrino scattering on electron or nucleon targets, atomic…

High Energy Physics - Phenomenology · Physics 2017-09-13 Adam Falkowski , Martín González-Alonso , Kin Mimouni

We reanalyse leptogenesis via the out-of-equilibrium decay of the lightest right-handed neutrino in type II seesaw scenarios, taking into account flavour-dependent effects. In the type II seesaw mechanism, in addition to the type I seesaw…

High Energy Physics - Phenomenology · Physics 2008-11-26 Stefan Antusch

Starting from the general effective hamiltonian relevant to the $b\to s$ transitions, we derive the expressions for the full angular distributions of the $B \to K^{(\ast )} \ell_1 \ell_2$ decay modes, as well as for ${\cal B}(B_s \to…

High Energy Physics - Phenomenology · Physics 2016-09-12 Damir Becirevic , Olcyr Sumensari , Renata Zukanovich Funchal

Precision measures of electroweak and flavour observables, at both low and high energies, are highly complementary to direct searches for New Physics at high-energy colliders. Despite the discovery of the Higgs boson at the Large Hadron…

High Energy Physics - Phenomenology · Physics 2022-03-01 Jonathan Kriewald

The gauging of the lepton flavour group is considered in the Standard Model context and in its extension with three right-handed neutrinos. The anomaly cancellation conditions lead to a Seesaw mechanism as underlying dynamics for all…

High Energy Physics - Phenomenology · Physics 2017-02-15 R. Alonso , E. Fernandez Martinez , M. B. Gavela , B. Grinstein , L. Merlo , P. Quilez

The seesaw mechanism is the most popular explanation for the smallness of neutrino masses. However, its high scale makes direct tests impossible and only indirect signals at low energies are reachable for collider experiments. One of these…

High Energy Physics - Phenomenology · Physics 2015-03-17 Avelino Vicente

We consider the low energy constraints that can be applied to type I see-saw extensions of the Standard Model in which the right-handed neutrinos are taken at the electroweak scale. In the reported scenarios, the flavour structure of the…

High Energy Physics - Phenomenology · Physics 2015-06-03 Emiliano Molinaro

We derive general constraints on the mixing of heavy Seesaw neutrinos with the SM fields from a global fit to present flavour and electroweak precision data. We explore and compare both a completely general scenario, where the heavy…

High Energy Physics - Phenomenology · Physics 2016-12-22 Enrique Fernandez-Martinez , Josu Hernandez-Garcia , Jacobo Lopez-Pavon

Current experimental information on the charm meson decay observables in which the $c\to s\ell\nu_\ell$ transitions occur is well compatible with the Standard Model predictions. Recent precise lattice calculations of the $D_s$ meson decay…

High Energy Physics - Phenomenology · Physics 2015-05-13 Svjetlana Fajfer , Ivan Nisandzic , Ursa Rojec

We consider an extension of the Standard Model with three right-handed neutrinos, endowed with a flavour symmetry $G_f$, $G_f=\Delta (3 \, n^2)$ or $G_f=\Delta (6 \, n^2)$, $n \geq 2$, and CP. For large active-sterile mixing, we study the…

High Energy Physics - Phenomenology · Physics 2024-12-16 Marco Drewes , Yannis Georis , Claudia Hagedorn , Juraj Klaric

The right--handed neutrino mass matrix that is central to the understanding of small neutrino masses via the seesaw mechanism can arise either (i) from renormalizable operators or (ii) from nonrenormalizable or super-renormalizable…

High Energy Physics - Phenomenology · Physics 2009-11-07 K. S. Babu , B. Dutta , R. N. Mohapatra

We analyse a flavour model for a lepton sector which is based on type I seesaw mechanism, a Z_2 symmetry for lepton flavours, a mu-tau interchange symmetry and a CP symmetry. This model fits well the data of neutrino mass squared…

High Energy Physics - Phenomenology · Physics 2015-10-19 Darius Jurciukonis , Thomas Gajdosik , Andrius Juodagalvis

The Minimal R-symmetric Supersymmetric Standard Model with Seesaw (MRSSMSeesaw) extends the MRSSM by incorporating right-handed neutrinos to generate neutrino masses via the Type-I seesaw mechanism. This work presents a detailed analysis of…

High Energy Physics - Phenomenology · Physics 2026-01-06 Hao-Yi Liu , Jin-Lei Yang , Ke-Sheng Sun , Tai-Fu Feng

In minimal supersymmetric seesaw models, the contribution to lepton flavour violation from Z-penguins is usually negligible. In this study, we consider the supersymmetric inverse seesaw and show that, in this case, the Z-penguin…

High Energy Physics - Phenomenology · Physics 2013-12-20 Cedric Weiland

Leptoquarks enter in several extensions of the Standard Model as possible solutions to a number of observed anomalies. We work within the soft-collinear effective theory framework to present a detailed analysis of the decay rates of the…

High Energy Physics - Phenomenology · Physics 2022-11-17 Bianka Mecaj , Matthias Neubert