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Related papers: Unitarity Constraints on Dimension-six Operators I…

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A revised and complete list of the electroweak chiral lagrangian operators up to dimension-four is provided. The connection of these operators to the $S$, $T$ and $U$ parameters and the parameters describing the triple gauge boson vertices…

High Energy Physics - Phenomenology · Physics 2009-10-22 T. Appelquist , G. Wu

Despite a large experimental effort, so far no evidence for flavour-violating decays of charged leptons such as $l_i\to l_j\gamma$ and $l_i\to l_j l_k l_k$ has been found. The absence of a signal puts very severe constraints on many…

High Energy Physics - Phenomenology · Physics 2017-05-11 Giovanni Marco Pruna , Adrian Signer

In this talk, we report unitarity constraints and phenomenological studies at the Large Hadron Collider for the extra Higgs bosons of a Composite 2-Higgs Doublet Model.

High Energy Physics - Phenomenology · Physics 2016-12-16 Stefania De Curtis , Stefano Moretti , Kei Yagyu , Emine Yildirim

Measurement of the Yukawa interaction between the top quark and the Higgs boson should be useful to clarify the mechanism of fermion mass generation. We discuss the impact of non-standard interactions characterized by dimension-six…

High Energy Physics - Phenomenology · Physics 2016-09-06 Shinya Kanemura , Daisuke Nomura , Koji Tsumura

New physics realized above the electroweak scale can be encoded in a model independent way in the Wilson coefficients of higher dimensional operators which are invariant under the Standard Model gauge group. In this article, we study the…

High Energy Physics - Phenomenology · Physics 2018-11-12 Jason Aebischer , Andreas Crivellin , Matteo Fael , Christoph Greub

Higgs couplings are essential probes for physics beyond the Standard Model (BSM) since they can be modified by new physics, such as through the Higgs portal interaction $|H|^2\mathcal{O}$. These modifications influence Higgs interactions…

High Energy Physics - Phenomenology · Physics 2024-08-20 Yunjia Bao , Jiayin Gu , Zhen Liu , Chi Shu , Lian-Tao Wang

We have investigated the signal for physics beyond the Standard Model via Higgs plus photon final state, hitherto unobserved at the LHC, in the framework of Standard Model Effective Field Theory. Using the relevant dimension-6 operators, we…

High Energy Physics - Phenomenology · Physics 2023-05-17 Tisa Biswas , Anindya Datta

We use the results of Maher {\em et al.\/} (preceding paper) to construct the matrix of $j=0$ partial-wave two-body and $2\rightarrow3$ scattering amplitudes for the scattering of longitudinally polarized gauge bosons $W_L^\pm$, $Z_L$ and…

High Energy Physics - Phenomenology · Physics 2009-10-22 Loyal Durand , Peter N. Maher , Kurt Riesselmann

We study the next-to-leading order electroweak corrections to Higgs processes from dimension-six top-quark operators in the Standard Model Effective Field Theory approach. We consider the major production channels, including $WH$, $ZH$, and…

High Energy Physics - Phenomenology · Physics 2018-10-02 Eleni Vryonidou , Cen Zhang

We study the phenomenology of both the Neutral Current (NC) and Charged Current (CC) Drell-Yan (DY) processes at the Large Hadron Collider (LHC) within a 4 Dimensional realization of a Composite Higgs model with partial compositness by…

High Energy Physics - Phenomenology · Physics 2017-05-11 D. Barducci , A. Belyaev , S. De Curtis , S. Moretti , G. M. Pruna

Below the electroweak scale, new physics that violates lepton number in two units ($\Delta L = 2$) and is mediated by heavy particle exchange can be parameterized by a dimension-9 low-energy effective Lagrangian. Operators in this…

High Energy Physics - Phenomenology · Physics 2025-03-11 Marcela González , Nicolás A. Neill

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

Physics beyond the Standard Model, realized above the electroweak scale, can be incorporated in a model independent way in the Wilson coefficients of higher dimensional gauge invariant operators. In these proceedings we review the matching…

High Energy Physics - Phenomenology · Physics 2016-06-09 Jason Aebischer , Andreas Crivellin , Matteo Fael , Christoph Greub

We investigate the potential of the $pp\to \gamma\gamma\gamma$ process to probe CP-conserving and CP-violating dimension-six operators of Higgs-gauge boson interactions in a model-independent Standard Model effective field theory framework…

High Energy Physics - Phenomenology · Physics 2019-09-20 H. Denizli , K. Y. Oyulmaz , A. Senol

Precision measurements of top-quark decays provide powerful probes of physics beyond the Standard Model (SM). While the impact of dimension-6 operators in the SM Effective Field Theory (SMEFT) has been extensively studied, the role of…

High Energy Physics - Phenomenology · Physics 2026-05-04 Afsaneh Kianfar , Gholamhossein Haghighat , Mojtaba Mohammadi Najafabadi

We study the collider phenomenology of the electroweak phase transition and electroweak baryogenesis in the framework of the effective field theory. Our study shows that the effective theory using the dimension-6 operators can enforce…

High Energy Physics - Phenomenology · Physics 2016-05-25 Fa Peng Huang , Pei-Hong Gu , Peng-Fei Yin , Zhao-Huan Yu , Xinmin Zhang

We show that hadron colliders have an excellent reach for positivity tests on a class of diphoton operators. Due to the helicity selection rules, the relevant dimension-6 operators either do not contribute or are highly constrained by other…

High Energy Physics - Phenomenology · Physics 2025-12-05 Zhen Liu , Kun-Feng Lyu , Tong Arthur Wu

Wilson coefficients in dimension-six effective field theory are constrained in a combined fit to several ATLAS measurements. These inputs probe Higgs-boson processes across multiple production and decay modes, di-Higgs signatures in the…

High Energy Physics - Experiment · Physics 2026-04-24 ATLAS Collaboration

We explain how one-loop amplitudes with massive fermions can be computed using only on-shell information. We first use the spinor-helicity formalism in six dimensions to perform generalised unitarity cuts in $d$ dimensions. We then show…

High Energy Physics - Phenomenology · Physics 2017-08-02 Simon Badger , Christian Brønnum-Hansen , Francesco Buciuni , Donal O'Connell

We study Higgs + jet production at hadron colliders in order to look for new physics residual effects possibly described by the $dim=6$ operators ${\O}_{GG}$ and ${\widetilde\O}_{GG}$ which induce anomalous $Hgg$ and $Hggg$ couplings. Two…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. J. Gounaris , J. Layssac , F. M. Renard