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We study those dimension 6 effective operators which generate flavor-changing quark-gluon transitions of the third generation quarks, with t -> g + u(c) and b -> g + d(s), and which could be of interest for LHC experiments. We analyze the…

High Energy Physics - Phenomenology · Physics 2010-10-21 Amand Faessler , Thomas Gutsche , Sergey Kovalenko , Valery E. Lyubovitskij , Ivan Schmidt

We present a generator for single top quark production via flavour-changing neutral currents. The MEtop event generator allows for Next-to-Leading-Order direct top production $pp \to t$ and Leading-Order production of several other single…

High Energy Physics - Phenomenology · Physics 2015-06-05 Rita Coimbra , António Onofre , Rui Santos , Miguel Won

We study the impact of dimension-six operators on single- and double-Higgs production rates via gluon fusion at the Large Hadron Collider (LHC). If the top-Yukawa coupling is modified by some new physics whose scale is of the TeV scale, its…

High Energy Physics - Phenomenology · Physics 2015-05-13 Shinya Kanemura , Koji Tsumura

We establish constraints on the dimension-six four-heavy-quark operators in the Standard Model Effective Field Theory (SMEFT) by synthesising LHC measurements of top-quark and single-Higgs production with electroweak precision observables.…

High Energy Physics - Phenomenology · Physics 2025-07-03 Stefano Di Noi , Hesham El Faham , Ramona Gröber , Marco Vitti , Eleni Vryonidou

We match the non-relativistic quark model, with both flavor dependent and flavor independent effective quark-quark interactions, to the spin-flavor operator basis of the 1/Nc expansion for the L=1 non-strange baryons. We obtain analytic…

Nuclear Theory · Physics 2016-02-10 Cintia Willemyns , Carlos Schat

We study the phenomenology of a strongly-interacting top quark at future hadron and lepton colliders, showing that the characteristic four-top contact operators give rise to the most significant effects. We demonstrate the extraordinary…

High Energy Physics - Phenomenology · Physics 2021-02-16 Giovanni Banelli , Ennio Salvioni , Javi Serra , Tobias Theil , Andreas Weiler

Recently, experimental collaborations have reported $\mathcal{O}(10)$ upper limits on the signal strength of four-top production at the LHC. Surprisingly, we find that the constraining power of four-top production on the $qqtt$ type of…

High Energy Physics - Phenomenology · Physics 2018-03-14 Cen Zhang

We study the effects of dimension six effective operators on the flavour violating production and decay of leptons at the International Linear Collider. Analytic expressions for the cross sections, decay widths and asymmetries of all…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. M. Ferreira , R. B. Guedes , R. Santos

An analysis of the flavour structure of dimension-6 effective field theory (EFT) operators in multilepton final states is presented, focusing on the interactions of quarks with Z bosons. For the first time, the flavour structure of these…

High Energy Physics - Experiment · Physics 2026-03-23 CMS Collaboration

At the HL-LHC and future high energy colliders, a sample of a billion top quarks will be produced, allowing precision searches for new physics in top quark decay and production. To aid in this endeavor, we characterize the independent three…

High Energy Physics - Phenomenology · Physics 2023-09-11 Layne Bradshaw , Spencer Chang

The single vector-like top partner hadroproduction in association with top quark in the five and the six-flavour schemes at the LHC is investigated. The inclusive cross section and the differential distributions are evaluated for many…

High Energy Physics - Phenomenology · Physics 2018-10-29 Mohamed Sadek Zidi

Motivated by the possibility that the right-handed top-quark (t_R) is composite, we discuss the effects of dimension-six operators on the Higgs boson production at the LHC. When t_R is the only composite particle among the Standard Model…

High Energy Physics - Phenomenology · Physics 2010-07-15 Daisuke Nomura

In absence of any distinct evidence of new physics phenomena at the LHC, an increasing number of experimental studies aim at probing anomalous effects with an effective field theory (EFT) that represents a comprehensive approach for…

High Energy Physics - Experiment · Physics 2019-10-11 Kirill Skovpen

Quark contact interactions are an important signal of new physics. We introduce a model in which the presence of a symmetry protects these new interactions from giving large corrections in flavor changing processes at low energies. This…

High Energy Physics - Phenomenology · Physics 2015-06-03 F. Bazzocchi , U. De Sanctis , M. Fabbrichesi , A. Tonero

We present a study of four top quark production at the LHC in the Standard Model Effective Field Theory (SMEFT). The analysis is performed at the tree-level, including all terms from the mixed QCD-EW-coupling cross-section expansion and all…

High Energy Physics - Phenomenology · Physics 2022-11-24 Hesham El Faham

In the context of $SU(2)_L\times U(1)$ dimension six operators we study the potential of the LHeC to provide information on top quark effective interactions. We focus on single antitop production and how it is affected not only by the…

High Energy Physics - Phenomenology · Physics 2015-06-03 I. A. Sarmiento-Alvarado , Antonio O. Bouzas , F. Larios

The Standard Model Effective Field Theory (SMEFT) is a universal way of parametrizing New Physics (NP) manifesting as new, heavy particle interactions with the Standard Model (SM) degrees of freedom, that respect the SM gauged symmetries.…

High Energy Physics - Phenomenology · Physics 2024-03-14 Luiz Vale Silva

The Large Hadron Collider (LHC) will open a new era in high energy physics. The expected large cross section for heavy flavour production in proton-proton collisions at $\sqrt{s}$ = 14 TeV will allow detailed studies of the production…

High Energy Physics - Experiment · Physics 2014-11-20 Alessandro Grelli , Andre Mischke

We explore the possibility that the right-handed top quark is composite, identifying possible signatures of compositeness and how they might manifest themselves at the LHC and Tevatron. We perform a complete analysis of the dimension six…

High Energy Physics - Phenomenology · Physics 2009-06-02 Kunal Kumar , Tim M. P. Tait , Roberto Vega-Morales

We compute the leading corrections to the differential cross section for top-pair production via gluon fusion due to dimension-six operators at leading order in QCD. The Standard Model fields are assumed to couple only weakly to the…

High Energy Physics - Phenomenology · Physics 2021-11-17 Christoph Müller