Related papers: Effective four-fermion operators in top physics: a…
Within a spontaneously broken gauge group we carefully analyse and calculate triple gauge boson vertices dominated by triangle one-loop Feynman diagrams involving heavy fermions compared to external momenta and gauge boson masses. We…
In the third fermion family and gauge symmetry of the Standard Model, we study the quark-quark, lepton-lepton and quark-lepton four-fermion operators in an effective theory at high energies. These operators have nontrivial contributions to…
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has…
We perform a model independent analysis on $q \bar{q} \rightarrow t \bar{t}$ using an effective lagrangian with dim-6 four-quark operators, and derive necessary conditions on new physics that are consistent with the $t\bar{t}$ production…
The robustness of translating effective operator constraints to BSM theories crucially depends on the mass and coupling of BSM particles. This is especially relevant for hadron colliders where the partonic centre of mass energy is around…
Renormalization factors for bilinear and four-quark operators with the Kogut-Susskind fermion action are perturbatively calculated to one-loop order in the general covariant gauge. Results are presented both for gauge invariant and…
We outline a general strategy for the non-perturbative renormalisation of composite operators in discretisations based on Neuberger fermions, via a matching to results obtained with Wilson-type fermions. As an application, we consider the…
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…
Events with $t$-channel single top quarks are used to probe effective field theory operators in $\sqrt{s}=13$ TeV proton-proton collision data corresponding to 140 fb$^{-1}$ recorded by the ATLAS detector at the Large Hadron Collider. An…
We study single top production at linear lepton colliders with $\sqrt{s} = 0.5$, 1 and 3 TeV. A preliminary analysis shows that despite the large $t\bar t$ background at $\sqrt{s} = 0.5$ and 1 TeV it is possible to obtain a good sensitivity…
We calculate the perturbative corrections to fermion bilinears that are used in numerical simulations when extracting weak matrix elements using staggered fermions. This extends previous calculations of Golterman and Smit, and Daniel and…
We present a complete and independent off-shell Green's basis of the dimension 8 operators in the Standard Model effective field theory (SMEFT). We propose an off-shell amplitude formalism such that this new kind of amplitudes has a…
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…
The production of an intermediate-mass Higgs boson in processes of the kind $e^+ e^- \to 6$ fermions at the energies of future linear colliders is studied. The recently developed and fully automatic algorithm/code ALPHA is used to compute…
In a companion paper, we show that operator bases for general effective field theories are controlled by the conformal algebra. Equations of motion and integration by parts identities can be systematically treated by organizing operators…
A simple algorithm is presented to decompose any 1-loop amplitude for scattering processes of the class 2 fermions -> 4 fermions into a fixed number of gauge-invariant form factors. The structure of the amplitude is simpler than in the…
We investigate systematically dimension-9 operators in the standard model effective field theory which contains only standard model fields and respects its gauge symmetry. With the help of the Hilbert series approach to classifying…
We compute the dimension 6 effective Lagrangian arising from the tree level integration of an arbitrary number of bulk fermions in models with warped extra dimensions. The coefficients of the effective operators are written in terms of…
We consider lepton flavour violating decays of the top quark, mediated by four-fermion operators. We compile constraints on a complete set of SU(3)*U(1)-invariant operators, arising from their loop contributions to rare decays and from…
The complete electroweak O(alpha) corrections have been calculated for the charged-current four-fermion production processes e+e- --> nu_tau tau+ mu- anti-nu_mu, u anti-d mu- anti-nu_mu, and u anti-d s anti-c. Here, technical details of…