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A composite Higgs boson of 125 GeV mass, only mildly fine-tuned, requires top partners with a semi-perturbative coupling and a mass not greater than about a TeV. We analyze the strong constraints on such picture arising from flavour and…

High Energy Physics - Phenomenology · Physics 2015-06-12 Riccardo Barbieri , Dario Buttazzo , Filippo Sala , David M. Straub , Andrea Tesi

This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly suppressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in $pp$…

High Energy Physics - Experiment · Physics 2023-11-14 ATLAS Collaboration

Flavor-breaking interactions due to heavy new physics can be probed at a 10 TeV muon collider in the high-energy production of quarks and leptons. The high collision energy mitigates the suppression of the new interactions, offering…

High Energy Physics - Phenomenology · Physics 2025-12-23 Alfredo Glioti , David Marzocca , Andrea Wulzer

The possibility of detecting double flavor violating top quark transitions at future colliders is explored in a model-independent manner using the effective Lagrangian approach through the $t \to u_i\tau \mu$ ($u_i=u,c$) decays. A Yukawa…

High Energy Physics - Phenomenology · Physics 2014-11-20 A. Fernandez , C. Pagliarone , F. Ramirez-Zavaleta , J. J. Toscano

The large integrated luminosity collected by the ATLAS detector at the LHC provides the opportunity to probe the presence of new physics that could enhance the rate of very rare processes in the Standard Model (SM). The LHC can therefore…

High Energy Physics - Experiment · Physics 2023-07-11 William George

A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=13$ TeV,…

High Energy Physics - Experiment · Physics 2018-08-13 ATLAS Collaboration

In supersymmetric grand-unified models, the lepton mixing matrix can possibly affect flavor-changing transitions in the quark sector. We present a detailed analysis of a model proposed by Chang, Masiero and Murayama, in which the…

High Energy Physics - Phenomenology · Physics 2015-05-27 Jennifer Girrbach , Sebastian Jager , Markus Knopf , Waldemar Martens , Ulrich Nierste , Christian Scherrer , Soren Wiesenfeldt

We present the sensitivity to Flavor Changing Neutral Currents (FCNC) in interactions involving the top quark at future $e^+e^-$ and $\mu^+\mu^-$ machines. We consider the $Ztc$ vertex as well as four-fermion contact interactions involving…

High Energy Physics - Phenomenology · Physics 2026-01-22 Sagar Airen , Roberto Franceschini

Flavour changing effects originating from the exchange of scalar particles in the processes e^+ e^- -> H b \bar{s}, H \bar{b} s, with H = h^0, H^0, A^0, are investigated in the Minimal Supersymmetric Standard Model with non-minimal flavour…

High Energy Physics - Phenomenology · Physics 2009-01-07 W. Hollik , S. Penaranda , M. Vogt

We investigate the constraints on flavour-changing neutral heavy Higgs-boson decays H-> b \bar s from b -> s gamma bounds on the flavour-mixing parameters of the MSSM with non-minimal flavour violation (NMFV). In our analysis we include the…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. Hahn , W. Hollik , J. I. Illana , S. Penaranda

We present a search for flavor changing neutral currents via quark-gluon couplings in a sample of single top quark final states corresponding to 2.3 fb^-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron…

High Energy Physics - Experiment · Physics 2010-09-28 D0 Collaboration , V. Abazov

We study the rare top-quark decay t->ch, where h is a generic Higgs boson, at a linear collider. If kinematically accessible, all models contain this decay at some level due to quark flavor mixing. Some models, such as Model III of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Tao Han , Jing Jiang , Marc Sher

The latest searches for flavor changing neutral currents (FCNCs) and measurements of properties in top quark events at the CMS and ATLAS experiments are presented. The vast amounts of proton-proton collision data recorded during the CERN…

High Energy Physics - Experiment · Physics 2023-06-14 Gerrit Van Onsem

CP4 3HDM is a peculiar three-Higgs-doublet model in which a single symmetry leads to tight constraints on the scalar and Yukawa sectors. In this models, tree-level flavor-changing neutral couplings are unavoidable; however, as previously…

High Energy Physics - Phenomenology · Physics 2025-11-26 Duanyang Zhao , Igor P. Ivanov

We study LHC Higgs signatures from topflavor seesaw realization of electroweak symmetry breaking with a minimal gauge extension SU(2) x SU(2) x U(1). This elegant renormalizable construction singles out top quark sector (instead of all…

High Energy Physics - Phenomenology · Physics 2013-06-07 Xu-Feng Wang , Chun Du , Hong-Jian He

The possibility of an anomalous coupling between the top and charm quarks and the gluon field is explored in a model-independent way using an effective Lagrangian that is gauge-invariant under a non-linear realization of SU(3)$_{C} \times$…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ehab Malkawi , Tim Tait

We present benchmark points for LHC searches from flavored gauge mediation models, in which messenger-matter couplings give flavor-dependent squark masses. Our examples include spectra in which a single squark - stop, scharm, or sup - is…

High Energy Physics - Phenomenology · Physics 2016-08-24 N. Ierushalmi , S. Iwamoto , G. Lee , V. Nepomnyashy , Y. Shadmi

A supersymmetric extension of the standard model based on the discrete $Q_6$ family symmetry is considered, and we investigate flavor-changing neutral current (FCNC) processes, especially those mediated by heavy flavor-changing neutral…

High Energy Physics - Phenomenology · Physics 2008-11-26 Naoko Kifune , Jisuke Kubo , Alexander Lenz

A study of single top quark production via flavor changing neutral current interactions at $tq\gamma$ vertices is performed at future circular hadron electron collider. The signal cross sections for the processes $e^{-}p\to e^{-}W^{\pm}q+X$…

High Energy Physics - Phenomenology · Physics 2017-07-28 H. Denizli , A. Senol , A. Yilmaz , I. T. Cakir , H. Karadeniz , O. Cakir

Contact interactions are the low-energy footprints of New Physics, so ideally, constraints upon them should be as generic and model independent as possible. Hadron colliders search for four-quark contact interactions with incident valence…

High Energy Physics - Phenomenology · Physics 2015-06-18 Sacha Davidson , Sébastien Descotes-Genon