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We study low energy experimental constraints on an anomalous top-quark coupling associated with the flavor-changing neutral current vertex $Z \bar t c$. In view of these constraints, we discuss the experimental observability of the induced…

High Energy Physics - Phenomenology · Physics 2009-10-28 T. Han , R. D. Peccei , X. Zhang

In the Standard Model Effective Field Theory (SMEFT), operators involving the top quark are generally difficult to probe, and can generate sizable loop contributions to the electroweak precision observables, measured by past and future…

High Energy Physics - Phenomenology · Physics 2022-11-09 Yiming Liu , Yuhao Wang , Cen Zhang , Lei Zhang , Jiayin Gu

A search for flavour-changing neutral currents (FCNC) processes in proton-proton ($pp$) collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the CERN Large Hadron Collider (LHC) is presented. The analysed data…

High Energy Physics - Experiment · Physics 2018-12-05 Ana Peixoto

We analyze the scattering of fermions, Higgs and electroweak gauge bosons in order to obtain the partial-wave unitarity bounds on dimension-six effective operators, including those involving fermions. We also quantify whether, at the LHC…

High Energy Physics - Phenomenology · Physics 2017-09-13 Tyler Corbett , O. J. P. Éboli , M. C. Gonzalez-Garcia

Single top quark production is a powerful process to search for new physics signs. In this work we propose and investigate a search for top quark flavor changing neutral currents (FCNC) via a photon using direct single top quark production…

High Energy Physics - Phenomenology · Physics 2017-03-22 Reza Goldouzian , Barbara Clerbaux

These proceedings present a search for flavour-changing neutral-current (FCNC) interaction involving the top quark, Higgs boson and either the up or the charm quark, using 140 fb$^{-1}$ of 13 TeV proton--proton collision data from the ATLAS…

High Energy Physics - Experiment · Physics 2026-02-04 Shayma Wahdan , On behalf of the ATLAS collaboration

In the Standard Model (SM), flavour changing neutral current (FCNC) top decays, possible at loop level only, are very strongly suppressed. Observation of any such decay would be a direct signature of physics beyond the SM. Large…

High Energy Physics - Experiment · Physics 2017-09-13 Aleksander Filip Żarnecki

In this Thesis we have investigated some effects appearing in top quark and Higgs boson decays with flavor changing neutral currents (FCNC) in the framework of generic Two Higgs Doblet Models (2HDM) and the Minimal Supersymmetric Standard…

High Energy Physics - Phenomenology · Physics 2007-05-23 Santi Bejar

We study the electroweak first-order electroweak phase transition (FO-EWPT) within the Standard Model Effective Field Theory (SMEFT) framework induced by dimension-6 operators. Such phenomena can be probed independently via…

High Energy Physics - Phenomenology · Physics 2025-12-05 Sahabub Jahedi , Indrajit Saha , Abhik Sarkar

The production of a single top quark in the $t$-channel and its subsequent decay is studied at NLO accuracy in QCD, augmented with the relevant dimension-6 effective operators from the Standard Model Effective Theory. We examine various…

High Energy Physics - Phenomenology · Physics 2018-12-05 M. de Beurs , E. Laenen , M. Vreeswijk , E. Vryonidou

In this paper, we examine the sensitivity of the three-top quark production at the LHC to the top quark flavor-changing neutral currents (FCNC) as well as the sensitivity of the four-top production to the strong and weak dipole moments of…

High Energy Physics - Phenomenology · Physics 2018-11-05 Malihe Malekhosseini , Mehrdad Ghominejad , Hamzeh Khanpour , Mojtaba Mohammadi Najafabadi

We investigate the anomalous flavour changing neutral current (FCNC) interactions of top quark through the process $e^{-}p\to e^{-}W^{\pm}q+X$. We calculate the signal and background cross sections in electron proton collisions at Large…

High Energy Physics - Phenomenology · Physics 2017-08-18 I. Turk Cakir , A. Yilmaz , H. Denizli , A. Senol , H. Karadeniz , O. Cakir

The Tevatron, with $p\bar{p}$ collisions at $\sqrt{s}=$1.96 TeV, can produce all flavors of $B$ hadrons and allows for unprecedented studies in the $B$ physics sector. These range from measurements of $B$ hadron properties to searches of…

High Energy Physics - Experiment · Physics 2015-03-17 S. Malde

The Standard Model (SM) has no flavor-changing neutral current (FCNC) processes at the tree level. Therefore, processes featuring FCNC in new physics are tightly constrained by data. Typically, the lower bounds on the scale of new physics…

High Energy Physics - Phenomenology · Physics 2023-12-05 S. Kovalenko , A. S. de Jesus , A. R. Zerwekh , Y. M. Oviedo-Torres , F. S. Queiroz , T. B. de Melo , J. P. Neto , Y. S. Villamizar

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

A search for flavour-changing neutral current (FCNC) processes in top-quark decays is presented. Data collected from proton-proton collisions at the LHC at a centre-of-mass energy of $\sqrt{s}=13$ TeV corresponding to an integrated…

High Energy Physics - Experiment · Physics 2019-08-13 A. Durglishvili

We examine the charged lepton flavor violating process $gg \rightarrow \mu^\pm \tau^\mp$ at the $\sqrt{s} = 13$ TeV LHC. Operators generating this process can be induced by new physics (NP) at dimension 8. Despite the power suppression…

High Energy Physics - Phenomenology · Physics 2018-09-10 Bhubanjyoti Bhattacharya , Robert Morgan , James Osborne , Alexey A. Petrov

We show that the correct perturbation theory for mixed fermion states leads to nonvanishing contributions of the dimension-four vertex operators for flavour-changing transitions. Their contributions to the amplitude are of the same order of…

High Energy Physics - Phenomenology · Physics 2022-03-02 D. Palle

We study the one-loop contributions of the effective flavor changing neutral couplings (FCNC) tcZ and tcH on the electroweak precision observables Gamma_Z, R_c, R_b, R_l, A_c and A^FB_c. Using the known experimental limits on these…

High Energy Physics - Phenomenology · Physics 2009-11-10 F. Larios , R. Martinez , M. A. Perez

We study flavor changing neutral current decays of the top quark in the context of general warped extra dimensions, where the five dimensional metric is slightly modified from 5D anti-de-Sitter (AdS$_5$). These models address the…

High Energy Physics - Phenomenology · Physics 2016-08-10 Alfonso Diaz-Furlong , Mariana Frank , Nima Pourtolami , Manuel Toharia , Reyna Xoxocotzi