Global analyses in the Standard Model Effective Field Theory (SMEFT) framework serve as a tool to probe potential directions of new physics. To break degeneracies between the Wilson coefficients of the SMEFT, it is essential to combine observables from various experiments. Since different observables entering global fits may be measured at different energy scales, it becomes increasingly important to account for this fact through the renormalisation group evolution (RGE) of the Wilson coefficients. In this work, we investigate the effects of the RGE on a global SMEFT fit under the assumption of a U(3)^5 symmetry within the minimal flavour violation framework. We comment on the role of next-to-leading order SMEFT predictions for breaking potential degeneracies between Wilson coefficients arising as a result of RGE effects.

We present an analysis of the sensitivity of current and future LHC searches for new spin-0 particles in top–anti-top-quark (tt) final states, focusing on generic axion-like particles (ALPs) that are coupled to top quarks and gluons. As a first step, we derive new limits on the effective ALP Lagrangian in terms of the Wilson coefficients ct and c_∼G based on the results of the CMS search using 35.9 fb−1 of data, collected at √(s) = 13 TeV. We then investigate how the production of an ALP with generic couplings to gluons and top quarks can be distinguished from the production of a pseudoscalar which couples to gluons exclusively via a top-quark loop. To this end, we make use of the invariant tt mass distribution and angular correlations that are sensitive to the tt spin correlation. Using a mass of 400 GeV as an example, we find that already the data collected during Run 2 and Run 3 of the LHC provides an interesting sensitivity to the underlying nature of a possible new particle. We also analyze the prospects for data anticipated to be collected during the high-luminosity phase of the LHC. Finally, we compare the limits obtained from the tt searches to existing experimental bounds from LHC searches for narrow di-photon resonances, from measurements of the production of four top quarks, and from global analyses of ALP–SMEFT interference effects.

We implement electroweak renormalisation schemes involving the effective weak mixing angle to NLO in Standard Model Effective Field Theory (SMEFT). After developing the necessary theoretical machinery, we analyse a select set of electroweak precision observables in such input schemes. An attractive feature is that large corrections from top-quark loops appearing in other schemes are absorbed into the definition of the effective weak mixing angle. On the other hand, the renormalisation condition which achieves this involves a large number of flavour-specific SMEFT couplings between the $Z$ boson and charged leptons, motivating simple flavour assumptions such as minimal flavour violation for practical applications. The results of this paper provide a valuable new component for estimating systematic uncertainties in SMEFT fits by performing analyses in multiple input schemes.

We present an analysis of the sensitivity of LHC searches for new spin-0 particles produced via gluon-fusion and decaying into top-antitop-quark (t (t) over bar) final states to generic axion-like particles (ALPs) coupled to top-quarks and gluons. We derive new limits on the effective ALP Lagrangian in the linear representation in terms of the Wilson coefficients c(t) and c((G) over bar) based on the existing CMS search using 35 fb(-1) of proton-proton scattering data collected at root s = 13 TeV. We further investigate posssible distinctions between ALPs and pseudoscalar Higgs bosons as predicted by the Two Higgs doublet model (2HDM), and find that a distinction is possible with data anticipated to be collected during the high-luminosity phase of the LHC for a significant range of the effective ALP-gluon coupling.

Abstract We present comprehensive global fits of the SMEFT under the minimal minimal flavour violation (MFV) hypothesis, i.e. assuming that only the flavour-symmetric and CP-invariant operators are relevant at the high scale. The considered operator set is determined by this flavour assumption rather than the used datasets. We establish global limits on these Wilson coefficients using leading order and next-to-leading order SMEFT predictions for electroweak precision observables, Higgs, top, flavour and dijet data as well as measurements from parity violation experiments and lepton scattering. Our investigations reveal an intriguing crosstalk among different observables, underscoring the importance of combining diverse observables from various energy scales in global SMEFT analyses.

Abstract In the presence of axions or axion-like particles (ALPs) that couple to the Standard Model via dimension-five interactions, dimension-six SMEFT interactions are generated via renormalization-group evolution. As many of these SMEFT contributions are experimentally tightly constrained, this “ALP-SMEFT interference” can be used to derive indirect bounds on the ALP couplings to the Standard Model particles. We present a global analysis of the Wilson coefficients of the ALP effective Lagrangian based on Higgs, top, and low-energy data. The obtained bounds are model independent and are competitive or even stronger than direct bounds in the GeV to TeV ALP-mass range.

The choice of an electroweak (EW) input scheme is an important component of perturbative calculations in Standard Model Effective Field Theory (SMEFT). In this paper we perform a systematic study of three different EW input schemes in SMEFT, in particular those using the parameter sets MW, MZ, GF, MW, MZ, α, or α, MZ, GF. We discuss general features and calculate decay rates of Z and W bosons to leptons and Higgs decays to bottom quarks in these three schemes up to next-to-leading order (NLO) in dimension-six SMEFT. We explore the sensitivity to Wilson coefficients and perturbative convergence in the different schemes, and show that while the latter point is more involved than in the Standard Model, the dominant scheme-dependent NLO corrections are universal and can be taken into account by a simple set of substitutions on the leading-order results. Residual NLO corrections are then of similar size between the different input schemes, and performing calculations in multiple schemes can give a useful handle on theory uncertainties in SMEFT predictions and fits to data.

In this paper, we work with 16 different single scalar particle extensions of the Standard Model. We present the sets of dimension-6 effective operators and the associated Wilson coefficients as functions of model parameters after integrating out the heavy scalars up to 1-loop, including the heavy-light mixing, for each such scenario. Using the correspondence between the effective operators and the observables at electroweak scale, and employing Bayesian statistics, we compute the allowed ranges of new physics parameters that are further translated and depicted in 2-dimensional Wilson coefficient space in the light of the latest CMS and ATLAS data up to $137 \text{ fb}^{-1}$ and $139\text{ fb}^{-1}$, respectively. We also adjudge the status of those new physics extensions that offer similar sets of relevant effective operators. In addition, we provide a model-independent fit of $23$ Standard Model effective field theory Wilson coefficients using electroweak precision observables, single and di-Higgs data as well as kinematic distributions of di-boson production.

We investigate the interactions of a light scalar with the Higgs boson and second-generation fermions, which trigger new rare decays of the Higgs boson into 4μ, 2μ2γ, 6μ and 4μ2j. We recast current LHC searches to constrain these decays and develop new collider analyses for those channels which are only poorly tested by existing studies. With the currently collected data we can probe branching ratios as small as 1.5×10−5, 8.7×10−5, 5.7×10−8 and 1.6×10−7, respectively. For the High-Luminosity LHC run, considered here to involve 3 ab−1 of integrated luminosity, these numbers go down to 1.3×10−5, 2.0×10−6, 3.0×10−9 and 5.4×10−9, respectively. We also comment on other channels that remain still unexplored.

The determination of |Vub| in inclusive semileptonic B → Xuℓν decays will be among the pivotal tasks of Belle II. In this paper we study the potential and limitations of machine-learning approaches that attempt to reduce theory uncertainties by extending the experimentally accessible fiducial region of the B → Xuℓν signal into regions where the B → Xcℓν background is dominant. We find that a deep neural network trained on low-level single particle features offers modest improvement in separating signal from background, compared to BDT set-ups using physicist-engineered high-level features. We further illustrate that while the signal acceptance of such a deep neural network deteriorates in kinematic regions where the signal is small, such as at high hadronic invariant mass, neural networks which exclude kinematic features are flatter in kinematics but less inclusive in the sampling of exclusive hadronic final states at fixed kinematics. The trade-off between these two set-ups is somewhat Monte Carlo dependent, and we study this issue using the multipurpose event generator Sherpa in addition to the widely used B-physics tool EvtGen.

We constrain CP-violating charged and neutral anomalous triple gauge couplings using LHC measurements and projections of diboson and VBF Vjj production, both with subsequent leptonic decays. For triple gauge couplings involving W bosons we analyse differential asymmetries and interpret our results in the SMEFT at dimension-six. For neutral triple gauge couplings, which are dominantly constrained by high transverse-momentum bins, we present the resulting bounds in terms of a general anomalous couplings framework.

We consider the associated production of a Higgs boson and a photon in weak boson fusion in the Standard Model (SM) and the Standard Model Effective Field Theory (SMEFT), with the Higgs boson decaying to a pair of bottom quarks. Analysing events in a cut-based analysis and with multivariate techniques we determine the sensitivity of this process to the bottom-Yukawa coupling in the SM and to possible CP-violation mediated by dimension-6 operators in the SMEFT.

We study the Standard Model effective field theory ( ν SMEFT) extended with operators involving right-handed neutrinos, focussing on the regime where the right-handed neutrinos decay promptly on collider scales to a photon and a Standard Model neutrino. This scenario arises naturally for right-handed neutrinos with masses of the order m_N ∼ 0.1 … 10 GeV . We limit the relevant dimension-six operator coefficients using LEP and LHC searches with photons and missing energy in the final state as well as pion and tau decays. While bounds on new physics contributions are generally in the TeV scale for order one operator coefficients, some coefficients, however, remain very poorly constrained or even entirely evade bounds from current data. Consequently, we identify such weakly constrained scenarios and propose new searches for rare top and tau decays involving photons to probe potential new physics in the ν SMEFT parameter space. Our analysis highlights the importance of performing dedicated searches for new rare tau and top decays.

We estimate the reach of global Higgs analyses at a 27 TeV hadron collider in terms of Higgs couplings and in terms of a gauge-invariant effective Lagrangian, including invisible Higgs decays and the Higgs self-coupling. The new collider will indirectly probe new physics in the TeV range and allow for a meaningful test of the Higgs self-coupling also embedded in a global analysis.

Searches for invisible Higgs decays in weak boson fusion are a well-known laboratory for jets and QCD studies. We present a series of results on tagging jets and central jet activity. First, precision analyses of the central jet activity require full control of single top production in some analyses. Second, the rate dependence on the size of the tagging jets is not limited to weak boson fusion. For the first time, we show how subjet information on the tagging jets and on the additional jet activity can be used to extract the Higgs signal. The additional observables relieve some of the pressure on other, critical observables. Finally, we compare the performance of weak boson fusion and associated Higgs production.

The elucidation of the nature of new phenomena requires a multi-pronged approach to understand the essential physics that underlies it. As an example, we study the simplified model containing a new scalar singlet accompanied by vector-like quarks. To be specific, we investigate three models with [Formula: see text]-doublet, vector-like quarks with Yukawa couplings to a new scalar singlet and which also couple off-diagonally to corresponding Standard Model fermions of the first or third generation through the usual Higgs boson. We demonstrate that three classes of searches can play important and complementary roles in constraining this model. In particular, we find that missing energy searches designed for sparticle production, are also very sensitive to vector-like quarks.

Based on a vector triplet model we study a possible failure of dimension-6 operators in describing LHC Higgs kinematics. First, we illustrate that including dimension-6 contributions squared can significantly improve the agreement between the full model and the dimension-6 approximation, both in associated Higgs production and in weak-boson-fusion Higgs production. Second, we test how a simplified model with an additional heavy scalar could improve the agreement in critical LHC observables. In weak boson fusion we find an improvement for virtuality-related observables at large energies, but at the cost of sizeable deviations in interference patterns and angular correlations.

Based on a vector triplet model, we study a possible failure of dimension-6 operators in describing LHC Higgs kinematics. First, we illustrate that including dimension-6 contributions squared can significantly improve the agreement between the full model and the dimension-6 approximation, both in associated Higgs production and in weak-boson-fusion Higgs production. Second, we test how a simplified model with an additional heavy scalar could improve the agreement in critical LHC observables. In weak boson fusion, we find an improvement for virtuality related observables at large energies, but at the cost of sizeable deviations in interference patterns and angular correlations.

We study constraints on new physics from Higgs production at the LHC in the context of an effective field theory (EFT), focusing on Higgs searches in HV (V = W, Z) associated production which are particularly sensitive to the high-energy behavior of certain dimension-six operators. We show that analyses of these searches are generally dominated by a kinematic region where the generic EFT expansion breaks down, and we establish under which conditions they can nevertheless be meaningful. For example, constraints from these searches on the Wilson coefficients of operators whose effects grow with energy can be established in scenarios where a particular combination of fermions and the Higgs are composite and strongly coupled: then, bounds from Higgs physics at high energy are complementary to LEP1 and competitive with LEP2.