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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

We derive, in the framework of soft-collinear effective field theory (SCET), a Lagrangian describing the $t$-channel exchange of Glauber quarks in the Regge limit. The Glauber quarks are not dynamical, but are incorporated through non-local…

High Energy Physics - Phenomenology · Physics 2018-04-04 Ian Moult , Mikhail P. Solon , Iain W. Stewart , Gherardo Vita

We present results for the non-perturbative renormalisation of four-fermion operators with two flavours of dynamical quarks. We consider both fully relativistic left current-left current operators, and a full basis for $\Delta B=2$…

High Energy Physics - Lattice · Physics 2008-11-26 P. Dimopoulos , G. Herdoiza , F. Palombi , M. Papinutto , C. Pena , A. Vladikas , H. Wittig

Effective Lagrangians can be used to parametrize the effects of physics beyond the standard model. Assuming the complete theory is a gauge theory, we determine which effective operators may be generated at tree level, and which are only…

High Energy Physics - Phenomenology · Physics 2009-10-28 C. Arzt , M. B. Einhorn , J. Wudka

The high energy (Regge) limit provides a playground for understanding all loop structures of scattering amplitudes, and plays an important role in the description of many phenomenologically relevant cross-sections. While well understood in…

High Energy Physics - Phenomenology · Physics 2024-09-02 Anjie Gao , Ian Moult , Sanjay Raman , Gregory Ridgway , Iain W. Stewart

We compute the one-loop anomalous dimensions of the low-energy effective Lagrangian below the electroweak scale, up to terms of dimension six. The theory has 70 dimension-five and 3631 dimension-six Hermitian operators that preserve baryon…

High Energy Physics - Phenomenology · Physics 2024-03-21 Elizabeth E. Jenkins , Aneesh V. Manohar , Peter Stoffer

Anomalous interactions involving the top quark contribute to some of the most difficult observables to directly access experimentally. They can give however a sizeable correction to very precisely measured observables at the loop level.…

High Energy Physics - Phenomenology · Physics 2015-11-18 Jorge de Blas , Mikael Chala , Jose Santiago

The process of top quark pair production at Next Linear Collider (NLC) has been considered adopting an effective Lagrangian approach and including all operators of dim~6 which can be tree-level-generated within unknown underlying theory.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Bohdan Grzadkowski

We discuss the phenomenology of right-handed charged currents in the framework of the Standard Model Effective Field Theory, in which they arise due to a single gauge-invariant dimension-six operator. We study the manifestations of the nine…

High Energy Physics - Phenomenology · Physics 2017-05-23 S. Alioli , V. Cirigliano , W. Dekens , J. de Vries , E. Mereghetti

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 heavy quark effective field theory Lagrangian is renormalized to order 1/m^2. Our technique eliminates operators that vanish by the equation of motion by continuously redefining the heavy quark fields during renormalization. It is…

High Energy Physics - Phenomenology · Physics 2009-10-28 Markus Finkemeier , Matt McIrvin

Precision measurements of high energy top quarks at the LHC constitute a powerful probe of new physics. We study the effect of four fermion operators involving two tops and two light quarks on the high energy tail of the $t\bar t$ invariant…

High Energy Physics - Phenomenology · Physics 2019-02-20 Marco Farina , Cristina Mondino , Duccio Pappadopulo , Joshua T. Ruderman

We consider top quark decay in the Standard Model Effective Field Theory (SMEFT). We present a calculation of the total decay width and the $W$-boson helicity fractions at next-to-leading order (NLO) in SMEFT. Our result includes the…

High Energy Physics - Phenomenology · Physics 2019-12-23 Radja Boughezal , Chien-Yi Chen , Frank Petriello , Daniel Wiegand

Focusing on four-Higgs interactions, we analyse the robustness of tree-level-derived positivity bounds on Standard Model effective field theory (SMEFT) operators under quantum corrections. Among other results, we demonstrate that: (i) Even…

High Energy Physics - Phenomenology · Physics 2022-06-29 Mikael Chala , Jose Santiago

We consider a generic class of effective quantum field theories with arbitrary gauge groups and scalar matter fields. In such theories, we derive the one-loop Renormalization Group Equations (RGEs) for the physical dimension-six operators.…

High Energy Physics - Phenomenology · Physics 2025-03-25 Mikołaj Misiak , Ignacy Nałęcz

We discuss the renormalisation properties of the full set of $\Delta F=2$ operators involved in BSM processes, including the definition of RGI versions of operators that exhibit mixing under RG transformations. As a first step for a fully…

High Energy Physics - Lattice · Physics 2018-01-30 Mauro Papinutto , Carlos Pena , David Preti

By analogy with pNRQCD, we construct Effective Field Theories suitable to describe the heavy-quark sector of baryons made of two and three heavy quarks. A long-standing discrepancy between the hyperfine splitting of doubly heavy baryons…

High Energy Physics - Phenomenology · Physics 2009-11-11 Nora Brambilla , Thomas Roesch , Antonio Vairo

We study four top quark production at hadron colliders in the Standard Model Effective Field Theory (SMEFT). We perform an analysis at the tree-level, including all possible QCD- and EW-coupling orders and relevant dimension-six operators.…

High Energy Physics - Phenomenology · Physics 2022-11-09 Rafael Aoude , Hesham El Faham , Fabio Maltoni , Eleni Vryonidou

The renormalization group evolution of $\Delta B=2$ transition operators is studied at leading order in heavy quark effective theory and at next-to-leading order in QCD. We calculate new contributions that were not taken into account in…

High Energy Physics - Phenomenology · Physics 2009-10-09 Gerhard Buchalla

New physics can manifest itself by an appreciable increase of the decay rate of top quarks in rare flavour-changing final states. Exploiting the large top quark production rate at the LHC, we bound four-fermion operators contributing to…

High Energy Physics - Phenomenology · Physics 2019-05-01 Mikael Chala , Jose Santiago , Michael Spannowsky