arXiv subjects

Ramona Gröber

Publications and source records attributed to Ramona Gröber.

At least 19 recordsLinked to original sources

arXiv2026

Higgs Boson Pair Production via Gluon Fusion: Higher-Order Corrections and Theoretical Uncertainties

In this contribution, the higher-order QCD and electroweak corrections to Standard Model Higgs boson pair production via the gluon-fusion mechanism, $gg\to hh$, are summarized and the different sources of theoretical uncertainty are assessed. The discussion includes finite top quark mass effects, matching to parton showers, approximate NNLO and N$^3$LO QCD corrections, NLO electroweak effects, and uncertainties associated with the top quark mass scheme and perturbative scale choices. In addition, we provide an updated state-of-the-art recommendation for the inclusive gluon-fusion Higgs boson pair production cross section and the corresponding Higgs boson pair invariant-mass distribution.

hep-ph↗

arXiv2026

Higgs boson pair production in SMEFT: shape and truncation studies

We present a comparative study of the influence of Wilson coefficients on Higgs boson pair production cross sections in SMEFT up to dimension-6, also including loop-suppressed operators. Our study accounts for NLO QCD corrections, and is based on updated parametrizations of the cross section as a polynomial in the Wilson coefficients. We focus on differential distributions for the Higgs boson pair invariant mass, as well as the transverse momenta of the leading Higgs bosons, identifying benchmark scenarios exhibiting pronounced shape distortions in the $m_{hh}$ and $p_{T,h}$ distributions. While some of these scenarios remain physically meaningful under a purely linear truncation of the SMEFT expansion, others yield unphysical differential cross sections when quadratic dimension-6 contributions are omitted, exposing the breakdown of the linear approximation for large anomalous couplings.

hep-ph↗

arXiv2026

Precise predictions for double Higgs production in association with a vector boson in Effective Field Theory

We present next-to-next-to-leading order (NNLO) QCD predictions for Higgs boson pair production in association with a weak gauge boson, $pp \to Vhh$ with $V=W^\pm,Z$, in effective field theory descriptions of new physics. We consider both the Standard Model Effective Field Theory (SMEFT), truncated at dimension six, and the Higgs Effective Field Theory (HEFT) at leading order in the chiral expansion. The calculation builds on the factorisation of the quark-induced production process into Drell-Yan production of an off-shell vector boson and its subsequent decay into $Vhh$, supplemented in the $Zhh$ channel by the loop-induced $gg \to Zhh$ contribution that first enters at NNLO QCD. We provide inclusive predictions at $\sqrt{s}=13.6$ and $14.0$ TeV, including scale, PDF, and $α_s$ uncertainties, and express the results in terms of numerical coefficients that allow fast evaluations for arbitrary EFT parameters in the considered ranges. We find that, for $W^\pm hh$ production, QCD corrections largely factorise from the EFT dependence, leading to almost flat $K$-factors. In contrast, $Zhh$ production shows a stronger dependence on the EFT coefficients because of the gluon-induced component.

hep-ph↗

arXiv2026

Constraining four-heavy-quark operators with top-quark, Higgs, and electroweak precision data

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. We scrutinise the choice of the $γ_5$ scheme in single-Higgs calculations, demonstrating its non-negligible impact on SMEFT fits.

hep-ph↗

arXiv2026

Electroweak Higgs boson pair production: Updated inclusive cross sections

We present updated inclusive cross sections for electroweak Higgs boson pair production for energies of relevance to the LHC and High-Luminosity phase of the LHC. The cross sections are presented at N$^3$LO QCD+NLO EW for vector-boson fusion and NNLO QCD for associate production with a vector boson. We compute the cross sections using the most up-to-date theory inputs, both in the Standard Model and for a few anomalous values of the trilinear Higgs self-coupling.

hep-ph↗

arXiv2026

Complete two-loop Yukawa-induced running of the Higgs-gluon coupling in SMEFT

We compute the two-loop renormalisation group equation for the effective Higgs to gluon coupling in Standard Model Effective Field Theory. Concretely, we present the contributions generated by the operators belonging to class 3 and 7 in the Warsaw basis, completing the two-loop renormalization program of the Higgs-gluon coupling proportional to the top Yukawa coupling for potentially tree-level generated operators. We investigate the phenomenological impact of the contributions in fits to Higgs data both in a bottom-up approach and a top-down approach in terms of UV models with vector-like quarks.

hep-ph↗

arXiv2026

Higgs pair production in gluon fusion to higher orders in Higgs Effective Field Theory

Higgs pair production offers the opportunity to probe correlations among the couplings of one or two Higgs bosons to fermions and gauge bosons. In this context, it serves as a powerful test of the underlying Effective Field Theory (EFT) framework. In particular, while such couplings remain correlated in the Standard Model Effective Field Theory (SMEFT) at dimension six, they can become fully de-correlated in Higgs Effective Field Theory (HEFT) already at leading order in the EFT expansion. In this work, we study Higgs pair production via gluon fusion within the HEFT framework. We demonstrate that adopting a consistent power counting in combination with next-to-leading order (NLO) diagrams necessitates the inclusion of higher-dimensional operators beyond the leading ones. We analyze their phenomenological impact and re-assess critically the kinematic benchmark scenarios commonly used in experimental non-resonant di-Higgs searches in light of these additional contributions.

hep-ph↗

arXiv2026

The Art of Counting: a reappraisal of the HEFT expansion

We revisit the power counting of the Higgs Effective Field Theory (HEFT) from first principles, by requiring that predictions for physical observables follow a series expansion in small, dimensionless quantities. Depending on whether HEFT is formulated in terms of a unique low-energy scale $v$ or in terms of two scales $v<f$, this approach identifies two viable power counting rules that can accommodate any operator normalization choice. We provide quantitative prescriptions for the consistent truncation of HEFT operators, amplitudes and observable contributions and we illustrate our arguments with a number of examples.

hep-ph↗

arXiv2026

Multi-Higgs Amplitudes Bootstrapped: Dissecting SMEFT and HEFT

The precise measurement of the Higgs boson properties requires a robust framework to parametrize possible deviations from Standard Model (SM) predictions in the most model-independent way possible. The Effective Field Theory (EFT) framework has become the most widely used since it offers a broad scope and a consistent path to increase the precision of the computations. Two prominent EFTs are the Standard Model Effective Field Theory (SMEFT) and the Higgs Effective Field Theory (HEFT). While similar in many aspects, their phenomenological differences are nowhere more pronounced than in multi-Higgs production. To precisely chart the separation between both EFTs, we study gluon-fusion double and triple Higgs production using bootstrapped on-shell amplitudes. This allows us to get the kinematic dependence of the gauge-invariant amplitude without field-redefinition ambiguities. As part of our study, we develop a technique that allows to build tree-level five-point on-shell amplitudes from lower-point on-shell amplitudes and bootstrapped contact terms. We then match the bootstrapped on-shell scattering amplitudes to the amplitudes computed in SMEFT (up to order $1/Λ^4$) and HEFT (at NNLO) and analyze the EFT order at which each kinematic structure appears. We also show how certain structures in $gg\to hhh$ appear only at dimension-12 in SMEFT or N$^3$LO in HEFT.

hep-ph↗

arXiv2026

Is the Standard Model Effective Field Theory Enough for Higgs Pair Production?

We study Higgs-boson pair production in the Standard Model Effective Field Theory (SMEFT) up to dimension six and in the Higgs Effective Field Theory (HEFT) at leading order in the effective theory expansion, and assess which description is appropriate in concrete UV scenarios. Motivated by "Loryon"-inspired models, we compare the Higgs pair production cross sections predicted by the full models to their SMEFT and HEFT counterparts. We identify regimes in which the two EFTs provide comparable descriptions, and clarify the limits required for their couplings to match. We also find that, for parts of parameter space in some of these models, HEFT can reproduce Higgs pair production more accurately than SMEFT, highlighting di-Higgs measurements as a potential probe of non-linear electroweak dynamics.

hep-ph↗

arXiv2025

Two-loop BSM contributions to Higgs pair production in the aligned THDM

We study the impact of the two-loop corrections controlled by the BSM Higgs couplings on the cross section for the production of a pair of SM-like Higgs bosons via gluon fusion in the aligned THDM. To this aim, we reassess the two-loop calculation of $λ_{hhh}$, we compute for the first time the two-loop corrections to $λ_{hhH}$, and we include the relevant corrections to the Higgs-gluon couplings and to the s-channel propagators entering the $gg \rightarrow hh$ amplitude. We discuss the numerical impact of the two-loop BSM contributions, first on the individual couplings and then on the prediction for the pair-production cross section, in two benchmark scenarios for the aligned THDM.

hep-ph↗

arXiv2025

Standard Model and SMEFT Higgs theory overview

After more than a decade from its discovery, the Higgs boson remains at the centre of the particle physics programme. While its couplings to vector bosons and third-generation fermions have been measured with impressive precision, the structure of the Higgs potential, the self-couplings, and the interactions with first- and second-generation fermions are still poorly constrained. This contribution summarises recent theoretical progress in precision predictions in Higgs physics, the interpretation of these results in Effective Field Theories (EFTs), and the current and future prospects to probe light Yukawa couplings at the LHC and beyond.

hep-ph↗

arXiv2025

$gg \to ZH$ : updated predictions at NLO QCD

We present state-of-the-art predictions for the inclusive cross section of gluon-initiated $ZH$ production, following the recommendations of the LHC Higgs Working Group. In particular, we include NLO QCD corrections, where the virtual corrections are obtained from the combination of a forward expansion and a high-energy expansion, and the real corrections are exact. The expanded results for the virtual corrections are compared in detail to full numerical results. The updated predictions show a reduction of the scale uncertainties to the level of 15%, and they include an estimate of the top-mass-scheme uncertainty.

hep-ph↗

arXiv2025

Two-loop running effects in Higgs physics in Standard Model Effective Field Theory

We consider the renormalization group equations within the Standard Model Effective Field Theory and compute two-loop contributions proportional to the top quark Yukawa coupling for the operator generating an effective Higgs-gluon coupling, focusing on the Yukawa-like operator. These two-loop running effects are relevant for processes where the effective Higgs-gluon coupling contributes at a lower loop order compared to the Standard Model contribution and where a dynamical scale choice is adopted. Such a situation arises, for instance, in the Higgs transverse momentum distribution and Higgs pair production. We investigate the phenomenological impact of our computations on these two processes and find that the two-loop contributions are significant and can lead to deviations of up to 20\% in the scenarios we consider.

hep-ph↗

arXiv2025

Two loops, four tops and two $γ_5$ schemes: a renormalization story

We calculate the four-top quark operator contributions to the two-loop renormalization constants of the fermion and gluon fields, necessary to obtain the renormalization group equations for the fermion masses and the strong coupling constant. The computation has been carried out in the na\"ıve dimensional regularization scheme for the $γ_5$ matrix. We also discuss a strategy to translate the results into the Breitenlohner--Maison--'t~Hooft--Veltman scheme and present the corresponding beta functions in both schemes.

hep-ph↗

arXiv2025

How large can the Light Quark Yukawa couplings be?

We investigate models that can induce significant modifications to the couplings of first- and second-generation quarks with Higgs bosons. Specifically, we identify all simplified models featuring two vector-like quark states which can lead to substantial enhancements in these couplings. In addition, these models generate operators in Standard Model Effective Field Theory, both at tree-level and one-loop, that are constrained by electroweak precision and Higgs data. We show how to evade constraints from flavour physics and consider direct searches for vector-like quarks. Ultimately, we demonstrate that viable ultraviolet models can be found with first-generation quark Yukawa couplings enhanced by several hundred times their Standard Model value, while the Higgs couplings to charm (strange) quarks can be increased by factors of a few (few tens). Given the importance of electroweak precision data in constraining these models, we also discuss projections for future measurements at the Tera-$Z$ FCC-ee machine.

hep-ph↗

arXiv2025

Probing New Physics with the Electron Yukawa coupling

A dedicated run of a future electron-positron collider (FCC-ee) at a center-of-mass energy equal to the Higgs boson mass would enable a direct measurement of the electron Yukawa coupling. However, it poses substantial experimental difficulties due to large backgrounds, the requirement for monochromatised $e^+e^-$ beams, and the potential extension of the FCC-ee timeline. Given this, we explore the extent to which the electron Yukawa coupling can be enhanced in simplified UV models and examine whether such scenarios can be constrained by other FCC-ee runs or upcoming experiments at the intensity frontier. Our results indicate that in certain classes of models, the $(g-2)_e$ provides a probe of the electron Yukawa coupling that is as effective or better than the FCC-ee. Nevertheless, there exist models that can lead to sizeable deviations in the electron Yukawa coupling which can only be probed in a dedicated run at the Higgs pole mass.

hep-ph↗

arXiv2024

Effective Field Theory descriptions of Higgs boson pair production

Higgs boson pair production is traditionally considered to be of particular interest for a measurement of the trilinear Higgs self-coupling. Yet it can offer insights into other couplings as well, since - in an effective field theory (EFT) parameterisation of potential new physics - both the production cross section and kinematical properties of the Higgs boson pair depend on various other Wilson coefficients of EFT operators. This note summarises the ongoing efforts related to the development of EFT tools for Higgs boson pair production in gluon fusion, and provides recommendations for the use of distinct EFT parameterisations in the Higgs boson pair production process. This document also outlines where further efforts are needed and provides a detailed analysis of theoretical uncertainties. Additionally, benchmark scenarios are updated. We also re-derive a parameterisation of the next-to-leading order (NLO) QCD corrections in terms of the EFT Wilson coefficients both for the total cross section and the distribution in the invariant mass of the Higgs boson pair, providing for the first time also the covariance matrix. A reweighting procedure making use of the newly derived coefficients is validated, which can be used to significantly speed up experimental analyses.

hep-ph↗