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Recent results from the LHC's first run have revealed intriguing departures from lepton flavour universality in the semi-leptonic decays of $B$-mesons. We discuss the complementary role that rare kaon decays can provide in testing new…

High Energy Physics - Phenomenology · Physics 2017-04-05 Lewis C. Tunstall , Andreas Crivellin , Giancarlo D'Ambrosio , Martin Hoferichter

The recent observation of the $K^+ \to \pi^+ \nu\bar\nu$ decay by NA62 is an important milestone in precision flavor physics. Together with evidence of $B^+ \to K^+\nu\bar\nu$ reported by Belle-II, they are the only FCNC decays involving…

High Energy Physics - Phenomenology · Physics 2025-01-30 Lukas Allwicher , Marzia Bordone , Gino Isidori , Gioacchino Piazza , Alfredo Stanzione

Partial compositeness is a key ingredient of models where the electroweak symmetry is broken by a composite Higgs state. Recently, a UV completion of partial compositeness was proposed, featuring a new strongly coupled gauge interaction as…

High Energy Physics - Phenomenology · Physics 2018-07-04 Francesco Sannino , Peter Stangl , David M. Straub , Anders Eller Thomsen

The latest search for the rare kaon decay $K^+\to\pi^+\nu\bar\nu$ by the NA62 experiment has produced evidence for it with a branching fraction consistent with the prediction of the standard model. The new result implies that in this decay,…

High Energy Physics - Phenomenology · Physics 2020-12-23 Chao-Qiang Geng , Jusak Tandean

We study the phenomenology of simplified $Z^\prime$ models with a global $U(2)^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation,…

High Energy Physics - Phenomenology · Physics 2020-05-13 Lorenzo Calibbi , Andreas Crivellin , Fiona Kirk , Claudio Andrea Manzari , Leonardo Vernazza

Our knowledge of flavour dynamics has undergone a `quantum jump' since just before the turn of the millenium: direct \cp violation has been firmly {\em established} in $K_L \to \pi \pi$ decays in 1999; the first \cp asymmetry outside $K_L$…

High Energy Physics - Phenomenology · Physics 2014-11-18 I. I. Bigi

Our knowledge of flavour dynamics has undergone a `quantum jump' since just before the turn of the millenium: direct \cp violation has been firmly {\em established} in $K_L \to \pi \pi$ decays in 1999; the first \cp asymmetry outside $K_L$…

High Energy Physics - Phenomenology · Physics 2007-05-23 I. I. Bigi

In this work we study possible connections between $B$-meson anomalies and Kaon physics observables in the context of combined solutions with the singlet and triplet scalar leptoquarks $S_1$ and $S_3$. By assuming a flavor structure for the…

High Energy Physics - Phenomenology · Physics 2022-04-27 David Marzocca , Sokratis Trifinopoulos , Elena Venturini

Searches for lepton flavour violation and lepton number violation in kaon decays by the NA62 and NA48/2 experiments at CERN are presented. A new measurement of the ratio of charged kaon leptonic decay rates…

High Energy Physics - Experiment · Physics 2011-07-05 Giuseppe Ruggiero

We calculate a number of observables related to particle-antiparticle mixing and the branching ratios for the most interesting rare and CP-violating K and B decays in the Standard Model (SM3) extended by a fourth generation of quarks and…

High Energy Physics - Phenomenology · Physics 2010-12-01 Andrzej J. Buras , Björn Duling , Thorsten Feldmann , Tillmann Heidsieck , Christoph Promberger , Stefan Recksiegel

Rare $K \to \pi \nu \bar \nu$ decays, being dominated by short distance contributions within the Standard Model (SM), open a window for New Physics (NP) searches at low energies. The $ K \to \pi \nu \bar\nu $ branching ratios are expected…

High Energy Physics - Phenomenology · Physics 2022-10-19 S. Fajfer , N. Košnik , L. Vale Silva

The latest measurements of rare $b\to s$ decays in the LHCb experiment have led to results in tension with the predictions of the standard model (SM), including a tentative indication of the violation of lepton flavor universality. Assuming…

High Energy Physics - Phenomenology · Physics 2015-08-31 Chao-Jung Lee , Jusak Tandean

We consider lepton-flavor violation in strangeness changing ($|\Delta S|=1$) semileptonic $\tau$-lepton decays arising from new physics encoded in a standard model effective Lagrangian. Its invariance under the standard model gauge group…

High Energy Physics - Phenomenology · Physics 2019-09-11 Xiao-Gang He , Jusak Tandean , German Valencia

Searches for the lepton number violating $K^{+} \rightarrow \pi^{-} \mu^{+} e^{+}$ decay and the lepton flavour violating $K^{+} \rightarrow \pi^{+} \mu^{-} e^{+}$ and $\pi^{0} \rightarrow \mu^{-} e^{+}$ decays are reported using data…

High Energy Physics - Experiment · Physics 2021-10-13 NA62 Collaboration

Recent Kaon decay studies seeking lepton-flavor violating (LFV) new-physics effects are briefly discussed. The main focus is set on precise measurements of rare or not-so-rare decays aiming at finding evidence of deviations from the SM…

High Energy Physics - Experiment · Physics 2009-06-02 T. Spadaro

We classify the extensions of the Standard Model (SM) according to the structure of local operators in the weak effective Hamiltonian and the presence or absence of new flavour and CP-violating interactions beyond those represented by the…

High Energy Physics - Phenomenology · Physics 2015-06-25 Andrzej J. Buras

Over the next years, the Flavour Physics community will be looking for inconsistencies of the Standard Model (SM) by exploiting new and precise measurements. In these ``indirect new physics'' searches, the key strategy is to concentrate on…

High Energy Physics - Phenomenology · Physics 2007-05-23 Federico Mescia

Motivated by recent results by the ATLAS and CMS collaborations on the angular distribution of the $B \to K^* \mu^+\mu^-$ decay, we perform a state-of-the-art analysis of rare $B$ meson decays based on the $b \to s \mu \mu$ transition.…

High Energy Physics - Phenomenology · Physics 2017-06-28 Wolfgang Altmannshofer , Christoph Niehoff , Peter Stangl , David M. Straub

With the running B, kaon and neutrino physics experiments, flavour physics takes centre stage within today's particle physics. We discuss the opportunities offered by these experiments in our search for new physics beyond the SM and discuss…

High Energy Physics - Phenomenology · Physics 2008-11-26 Tobias Hurth

The recently reported measurements of the CP asymmetry a(psi K) by the BABAR and BELLE collaborations are in good agreement with the standard model (SM) prediction, resulting from the unitarity of the CKM matrix. The so-called minimal…

High Energy Physics - Phenomenology · Physics 2010-05-28 A. Ali , E. Lunghi