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Flavour Changing Neutral Current (FCNC) decays are forbidden at lowest perturbative order in the Standard Model (SM) and only allowed via quantum loops. These transitions are therefore heavily suppressed in the SM, and New Physics (NP) can…

High Energy Physics - Experiment · Physics 2026-05-19 Christoph Langenbruch

Flavor changing neutral currents (FCNC) decays t to H + c, t to Z + c, and H to t + bar{c} are discussed in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions where FCNC decays may take place…

High Energy Physics - Phenomenology · Physics 2009-11-11 R. Gaitan , O. G. Miranda , L. G. Cabral-Rosetti

Predictions for LHC physics are given for a two-Higgs-doublet model having four generalized CP symmetries. In this maximally-CP-symmetric model (MCPM) the first fermion family is, at tree level, uncoupled to the Higgs fields and thus…

High Energy Physics - Phenomenology · Physics 2010-09-13 M. Maniatis , A. von Manteuffel , O. Nachtmann

We investigate an extension of the Standard Model containing two Higgs doublets and a singlet scalar field (2HDSM). We show that the model can have a strongly first-order phase transition and give rise to the observed baryon asymmetry of…

High Energy Physics - Phenomenology · Physics 2016-08-31 Tommi Alanne , Kimmo Kainulainen , Kimmo Tuominen , Ville Vaskonen

In this work we investigate the CP-conserving two-Higgs-doublet model (2HDM) in two realizations: a classically conformal setup (C2HDM) and a non-conformal setup with explicit tree-level quadratic mass terms (NC2HDM). Imposing current…

High Energy Physics - Phenomenology · Physics 2026-03-10 Nico Benincasa , Ji-Wei Li , Hanxiao Pu , Robert B. Mann , Vahid Shokrollahic , T. G. Steele , Zhi-Wei Wang

Large long-distance standard model effects in FCNC semileptonic D decays can make observable these processes in future measurements. Eventual disagreements in this sector and/or the observation of lepton family violating (LFV) D decays…

High Energy Physics - Phenomenology · Physics 2009-10-31 G. Lopez Castro , R. Martinez , J. H. Munoz

We conjecture the existence of a relation between elementary scalars and fermions, making it plausible the existence of three Higgs doublets. We introduce a Trinity Principle (TP) which, given the fact that there are no massless quarks,…

High Energy Physics - Phenomenology · Physics 2020-08-26 João M. Alves , Francisco J. Botella , Gustavo C. Branco , Miguel Nebot

A mechanism for double suppression of flavor-changing neutral currents (FCNCs) and CP violating phases in supersymmetric models is suggested. At M_{SUSY} they are suppressed due to a nonabelian discrete flavor symmetry, and the infrared…

High Energy Physics - Phenomenology · Physics 2011-07-19 Ki-Young Choi , Yuji Kajiyama , Hyun Min Lee , Jisuke Kubo

We study flavour-changing neutral current decays of the top quark in the democratic Three Higgs Doublet Model featuring a $Z_3$-symmetric scalar potential and Natural Flavour Conservation. In this framework, while such processes are absent…

High Energy Physics - Phenomenology · Physics 2026-01-26 Baradhwaj Coleppa , Benjamin Fuks , Akshat Khanna

It is possible that the standard model (SM) is replaced around some transition energy $\E_{tr}$ by a new, possibly Higgsless, ``flavor gauge theory'' such that the Yukawa (running) parameters of SM at $E \sim \E_{tr}$ show up an…

High Energy Physics - Phenomenology · Physics 2010-11-01 G. Cvetic , C. S. Kim

We build a class of two-Higgs-doublet models in which the flavour-changing couplings of the neutral scalars are related in an exact way to elements of the quark mixing matrix. In this framework, we explore the different possibilities for CP…

High Energy Physics - Phenomenology · Physics 2009-10-28 G. C. Branco , W. Grimus , L. Lavoura

In this work, we explore the viability of light-scalar scenarios within the $\mathcal{CP}$-conserving, flavour-aligned two-Higgs-doublet model (A2HDM), where at least one additional neutral or charged scalar is assumed to be lighter than…

High Energy Physics - Phenomenology · Physics 2025-05-14 V. Miralles , A. M. Coutinho , A. Karan , A. Pich

We study the effects of tree-level flavor changing neutral current and its present status with Cabibbo-Kobayashi-Maskawa matrix. Especially, we remark the effects of flavor changing neutral current on the unitary triangle of…

High Energy Physics - Phenomenology · Physics 2012-08-27 L. T. Handoko Pages , : , 73 pages

We illustrate the possibility of observing signals from Flavor Changing Neutral Currents, originating from the scalar sector of a Two Higgs Doublet Model. In particular, we focus on the tree level process mu^+ mu^- --> tbar c + cbar t, via…

High Energy Physics - Phenomenology · Physics 2009-10-30 Laura Reina

Two-Higgs-doublet models (2HDMs) with a flavored U(1)' gauge symmetry are a popular extension to the Standard Model (SM), yet they currently lack a complete survey. In this paper, we present a full classification of anomaly-free 2HDMs…

High Energy Physics - Phenomenology · Physics 2020-01-07 Astrid Ordell , Roman Pasechnik , Hugo Serôdio , Franz Teichmann

In extended Higgs models, a discrete symmetry is needed in the quark sector to avoid tree-level flavor-changing neutral currents. However, this is not necessary the case in the lepton sector. We consider a model in which one Higgs couples…

High Energy Physics - Phenomenology · Physics 2023-05-17 B. L. Gonçalves , Matthew Knauss , Marc Sher

A search for flavor-changing neutral currents (FCNC) in events with the top quark and the Higgs boson is presented. The Higgs boson decay to a pair of b quarks is considered. The data sample corresponds to an integrated luminosity of 35.9…

High Energy Physics - Experiment · Physics 2018-07-02 CMS Collaboration

We study a fermionic dark matter model in which the interaction of the dark and visible sectors is mediated by Higgs portal type couplings. Specifically, we consider the mixing of a dark sector scalar with the scalars of a Two Higgs Doublet…

High Energy Physics - Phenomenology · Physics 2018-01-19 Nicole F. Bell , Giorgio Busoni , Isaac W. Sanderson

Flavour Changing Neutral Current (FCNC) processes are forbidden at tree level in the Standard Model and highly suppressed at higher orders. This makes FCNC one of the key processes to search for new physics since any small deviations from…

High Energy Physics - Experiment · Physics 2019-08-14 J. P. Araque

We examine the decays $t\rightarrow c\gamma$ and $c Z^0$ in the Standard Model with an extra scalar doublet and no discrete symmetry preventing tree-level flavour changing neutral currents. The Yukawa couplings of the new scalars are…

High Energy Physics - Phenomenology · Physics 2009-10-22 Michael Luke , Martin J. Savage