English
Related papers

Related papers: Lepton Universality in Kaon Decays

200 papers

We investigate the relation between non-unitarity of the leptonic mixing matrix and leptogenesis. We discuss how all parameters of the canonical type-I seesaw mechanism can, in principle, be reconstructed from the neutrino mass matrix and…

High Energy Physics - Phenomenology · Physics 2011-05-23 Stefan Antusch , Steve Blanchet , Mattias Blennow , Enrique Fernandez-Martinez

The recent NA48/2 improvement on R_K=Gamma(K->e nu_e)/Gamma(K->mu nu_mu) emphasizes the role of K_l2 decays in probing the mu-e universality. Supersymmetric (SUSY) extensions of the Standard Model can exhibit mu-e non-universal…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Masiero , P. Paradisi , R. Petronzio

New heavy neutral leptons lead to non-unitary effects in models for neutrino masses. Such effects could represent a sign of new physics beyond the Standard Model, leading to observable deviations in neutrino oscillation experiments, lepton…

High Energy Physics - Phenomenology · Physics 2024-08-26 Jesús Miguel Celestino-Ramírez , G. Hernández-Tomé , O. G. Miranda , Eduardo Peinado

We construct an expression for a general lepton flavour universality (LFU) ratio, $R_{X}$, in $b\to s l^+ l^-$ decays in terms of a series of hadronic quantities which can be treated as nuisance parameters. This expression allows to include…

High Energy Physics - Phenomenology · Physics 2022-06-01 Gino Isidori , Davide Lancierini , Abhijit Mathad , Patrick Owen , Nicola Serra , Rafael Silva Coutinho

Mixing lepton doublets of the Standard Model can lead to lepton flavour asymmetries in the Early Universe. We present a diagrammatic representation of this recently identified source of $CP$ violation and elaborate in detail on the…

High Energy Physics - Phenomenology · Physics 2015-12-09 Bjorn Garbrecht , Ignacio Izaguirre

We study the model with three right-handed neutrinos which masses are smaller than the weak scale ${\cal O}(10^2)$ GeV (called as the $\nu$MSM). The model can explain the origin of neutrino masses by the seesaw mechanism, offer a candidate…

High Energy Physics - Phenomenology · Physics 2015-06-02 Takehiko Asaka , Shintaro Eijima , Kazuhiro Takeda

Recently, discrepancies of up to $4\,\sigma$ between the different determinations of the Cabibbo angle were observed. This "Cabibbo-angle anomaly" could be explained by lepton flavour universality (LFU) violating New Physics (NP) in the…

High Energy Physics - Phenomenology · Physics 2020-10-28 Antonio M. Coutinho , Andreas Crivellin , Claudio Andrea Manzari

In this doctoral thesis, we study both low- and high-energy observables related to massive neutrinos. Neutrino oscillations have provided indisputable evidence in favour of non-zero neutrino masses and mixings. However, the original…

High Energy Physics - Phenomenology · Physics 2013-11-25 Cédric Weiland

We write the neutrino mass eigenstate into the weak doublet of the group $SU(2)_L$ . The massive neutrino is written as the mixture of the flavor neutrino. The flavor changing Lagrangian of lepton-W boson coupling were obtained. The…

High Energy Physics - Phenomenology · Physics 2014-06-11 Ong Jian Fuh , Ithnin Abdul Jalil

We investigate whether the $2.6\sigma$ deviation from lepton flavour universality in $B^+\to K^+\ell^+\ell^-$ decays recently observed at the LHCb experiment can be explained in minimal composite Higgs models. We show that a visible…

High Energy Physics - Phenomenology · Physics 2015-08-10 Christoph Niehoff , Peter Stangl , David M. Straub

The lepton-flavour-violating decay K_L --> e \mu is studied in detail within the context of SU(2)_R x SU(2)_L x U(1)_(B-L) models, which include heavy Majorana neutrinos. Particular attention is paid to the gauge independence of this decay…

High Energy Physics - Phenomenology · Physics 2009-10-30 Zoltan Gagyi-Palffy , Apostolos Pilaftsis , Karl Schilcher

A possible extension of the Standard Model to include lepton number as local gauge symmetry is investigated. In such a model, anomalies are canceled by two extra fermions doublet. After leptonic gauge symmetry spontaneously broken, three…

High Energy Physics - Phenomenology · Physics 2011-01-03 Wei Chao

B-decays mediated by both charged currents and neutral currents have provided hints of violation of lepton flavour universality. By assuming an explanation of these anomalies in terms of new physics at the TeV scale affecting the third…

High Energy Physics - Phenomenology · Physics 2018-08-07 Ferruccio Feruglio

Even though the LHC searches did not unveil the new physics particles so far, LHCb hints towards deviations from lepton flavor universality in exclusive decays based on the transition $b\to s\ell\ell$. In this proceeding, we present a new…

High Energy Physics - Phenomenology · Physics 2017-10-25 Olcyr Sumensari

We explore the idea of quark-lepton unification at low energies. In particular, we discuss the minimal framework for matter unification at the multi-TeV scale, in which neutrino masses are necessarily generated via the inverse seesaw…

High Energy Physics - Phenomenology · Physics 2026-03-20 Hridoy Debnath , Pavel Fileviez Perez

We study the implications of a large $\nu_\mu - \nu_\tau$ mixing angle on lepton flavour violating radiative transitions in supersymmetric extensions of the standard model. The transition rates are calculated to leading order in $\epsilon$,…

High Energy Physics - Phenomenology · Physics 2014-11-17 W. Buchmuller , D. Delepine , F. Vissani

We consider a class of models predicting new heavy neutral fermionic states, whose mixing with the light neutrinos can be naturally significant and produce observable effects below the threshold for their production. We update the indirect…

High Energy Physics - Phenomenology · Physics 2016-09-01 D. Tommasini , G. Barenboim , G. Bernabeu , C. Jarlskog

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

We explore the possibility of lepton number violation (LNV) manifesting in the rare kaon decay $K\to\pi\nu\nu$, and its consequences for radiative neutrino mass generation and the washout of Lepton asymmetry in high-scale leptogenesis…

High Energy Physics - Phenomenology · Physics 2021-01-01 Frank F. Deppisch , Kåre Fridell , Julia Harz

Recent results from the intensity frontier indicate the tantalizing possibility of violation in lepton flavour universality. In light of this we revisit the minimal phenomenological $Z'$ model taking in account both vectorial and…

High Energy Physics - Phenomenology · Physics 2023-01-03 Tirtha Sankar Ray , Avirup Shaw