Abstract Precision flavour observables play an important role in the interpretation of results at the LHC in terms of models of new physics. We present the result for the one-loop Z penguin in generic extensions of the standard model which exhibit exact perturbative unitarity. We use Slavnov-Taylor identities to study the implications of unitarity on the renormalisation of the Z...
Abstract We calculate the contributions to the two-loop scattering amplitudes h → gg, h → ggg and \( h\to q\overline{q}g \) that arise from a modified trilinear Higgs coupling λ. Analytic expressions are obtained by performing an asymptotic expansion near the limit of infinitely heavy top quark. The calculated amplitudes are necessary to study the impact of the \( \mathcal{O...
In the framework of the Standard Model effective field theory, we examine the indirect constraints on the trilinear Higgs coupling λ that arise from Higgs production in gluon-gluon-fusion and diphoton Higgs decays. We calculate 2-loop contributions to the gg → h and h → γγ amplitudes that are affected by modifications of the trilinear Higgs-boson vertex. Based on our new results...
We examine the constraints on the trilinear Higgs coupling λ that originate from associated (V h) and vector boson fusion (VBF) Higgs production in pp collisions in the context of the Standard Model effective field theory. The 1-loop contributions to pp → Vh and pp → jjh that stem from insertions of the dimension-6 operator O 6 = −λ (H † H)3 are calculated and combined with the...
We use currently available data of nonleptonic charmless 2-body \(B\rightarrow MM\) decays (\(MM \!=\! PP, PV, VV\)) that are mediated by \(b\rightarrow (d, s)\) QCD- and QED-penguin operators to study weak annihilation and new-physics effects in the framework of QCD factorization. In particular we introduce one weak-annihilation parameter for decays related by \((u...
A discovery of flavour-changing Higgs-boson decays would constitute an undeniable signal of new physics. We derive model-independent constraints on the tch and tuh couplings that arise from the bounds on hadronic electric dipole moments. Comparisons of the present and future sensitivities with both the direct LHC constraints and the indirect limits from D-meson physics are also...
We present a new analysis of the ratio ε′/ε within the Standard Model (SM) using a formalism that is manifestly independent of the values of leading (V − A) ⊗ (V − A) QCD penguin, and EW penguin hadronic matrix elements of the operators Q 4, Q 9, and Q 10, and applies to the SM as well as extensions with the same operator structure. It is valid under the assumption that the SM...
Precise measurements of SM particles properties at the LHC allows to look for heavy New Physics in the context of an Effective Field Theory (EFT). These searches, however, often rely on kinematic regions where the validity of the EFT may be compromised. In this paper we propose to address this issue by comparing with benchmark models. The connection between models and their...
