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Konstantin Asteriadis

Publications and source records attributed to Konstantin Asteriadis.

10 recordsLinked to original sources
arXiv2026

One-loop QCD amplitudes for vector-boson-fusion Higgs-boson production to higher orders in $ε$

We consider one-loop QCD corrections to Higgs-boson production via vector-boson fusion at hadron colliders. As an input for future exact NNLO computations, we derive the one-loop helicity amplitudes to higher orders in the dimensional regulator. We present a direct calculation of the amplitudes with spinor-helicity techniques and different $γ_5$ schemes. In addition, we compare this approach to a projector-based calculation. In order to derive analytical results to higher orders in $ε$, we calculate the pentagon master integrals by the method of $ε$-factorised differential equations and express them in terms of an algebraically independent set of basis functions.

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arXiv2026

The $e^+ e^- \rightarrow Z H$ Process in the SMEFT Beyond Leading Order

We systematically study potential effects of Beyond the Standard Model physics in the $e^+ e^- \rightarrow Z H$ process. To this end, we include all relevant dimension-6 Standard Model Effective Field Theory operators and work to next-to-leading order (NLO) accuracy in the electroweak coupling. We consider both polarized and unpolarized electron and positron beams and present results for $\sqrt{s}=240, ~365$ and $500~{\rm GeV}$, emphasizing contributions where the NLO predictions differ significantly from the leading order results. At NLO, a sensitivity arises to operators that do not contribute at tree level, such as the Higgs tri-linear coupling, CP-violating operators, and dimension-6 operators involving the top quark, among many others. We compare the prospects of future $e^+e^-$ colliders to explore these new physics effects with existing measurements from the LHC, electron EDMs (for CP violating operators), and Z pole measurements.

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arXiv2024

Impact of NLO Weak SMEFT Corrections in $e^+e^- \rightarrow ZH$

We present results from a complete next-to-leading order (NLO) calculation of $e^+e^-\rightarrow ZH$ in the Standard Model Effective Field Theory (SMEFT) framework, including all contributions from dimension-6 operators. At NLO, there are novel dependencies on CP violating parameters in the gauge sector, on modifications to the Higgs boson self-couplings, on alterations to the top quark Yukawa couplings, and on 4-fermion operators involving the electron and the top quark, among others. We show that including only the logarithms resulting from renormalization group scaling can produce misleading results, and further, we explicitly demonstrate the constraining power of combining measurements from different energy scales.

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arXiv2024

QCD corrections to Higgs boson production and $H \to b \bar{b}$ decay in weak boson fusion

We study QCD corrections to the process where a Higgs boson is produced in weak boson fusion and then decays into a pair of massive $b$ quarks. We find that typical experimental criteria used to identify $b$ jets in this process affect QCD corrections to the decay, making it necessary to account for them in the proper description of this process. Indeed, if corrections to the production and decay are combined, the fiducial cross section of the weak boson fusion process $p p \to H(\to b \bar{b}) j j$ is reduced by about $40\%$ relative to leading-order predictions, compared to just about $8\%$ if only corrections to the production process are considered. We investigate the origin of these large corrections through next-to-next-to-leading-order and conclude that they appear because a number of independent moderately-large effects conspire to significantly reduce the fiducial cross section for this process.

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arXiv2024

Double insertions of SMEFT operators in gluon fusion Higgs boson production

Deviations from the Standard Model (SM) can be parameterized in terms of the SM effective field theory (SMEFT), which is typically truncated at dimension-6. Including higher dimension operators -- as well as considering simultaneous insertions of multiple dimension-6 operators -- may be necessary in some processes, in order to correctly capture the properties of the underlying UV theory. As a step towards clarifying this in the Higgs boson production in gluon fusion process, we study double insertions of dimension-6 operators in the 1-loop virtual amplitude. We present needed Feynman rules up to $\mathcal{O}(1/Λ^4)$ and we numerically study the impact of various approximations to the $\mathcal{O}(1/Λ^4)$ expansion.

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arXiv2023

Bremsstrahlung from Neutrino Scattering via Magnetic Dipole Moments

In this paper we discuss bremsstrahlung induced by neutrino scattering. This process should exist since neutrinos are expected to couple to photons via magnetic dipole and transition moments. These moments are loop-induced and tiny in the Standard Model with neutrino masses but could be significantly enhanced in extended theories. As concrete example we study the scattering of the two largest neutrino fluxes on earth, solar neutrinos and Cosmic Neutrino Background (CNB). It is tempting to consider this as a potential signature for CNB searches but it turns out that the signal is extremely small and unlikely to be observed.

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arXiv2023

On the non-factorizable corrections to Higgs boson production in weak boson fusion

We discuss the non-factorizable corrections to Higgs boson production in weak boson fusion at the Large Hadron Collider. Such corrections depend on the finite part of the two-loop virtual amplitude $q \, Q \rightarrow q^\prime \, Q^\prime + H$ which, up to now, has only been computed in the eikonal approximation. We combine this contribution with real-virtual and double-real non-factorizable QCD corrections and study their impact on the various observables in weak boson fusion. We find that the non-factorizable corrections are strongly dominated by the two-loop virtual contributions, while all other contributions play a very minor role. This striking imbalance between real and virtual contributions is caused by a process-specific kinematic suppression of the former and a particular enhancement of the virtual corrections related to a Glauber phase.

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arXiv2022

Anomalous Higgs boson couplings in weak boson fusion production at NNLO in QCD

The production of Higgs bosons in weak boson fusion has the second largest cross section among Higgs-production processes at the LHC. As such, this process plays an important role in detailed studies of Higgs interactions with vector bosons. In this paper we extend the available description of Higgs boson production in weak boson fusion by considering anomalous $HVV$ interactions and NNLO QCD radiative corrections at the same time. We find that, while leading order QCD predictions are too uncertain to allow for detailed studies of the anomalous couplings, NLO QCD results are sufficiently precise, most of the time. The NNLO QCD corrections alter the NLO QCD predictions only marginally, but their availability enhances the credibility of conclusions based on NLO QCD computations.

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arXiv2021

NNLO QCD corrections to weak boson fusion Higgs boson production in the $H \to b\bar b$ and $H \to WW^* \to 4l$ decay channels

We compute the next-to-next-to-leading order QCD corrections to Higgs boson production in weak boson fusion followed by its decay to a $b\bar b$ pair or to a pair of leptonically-decaying $W$ bosons. Our calculation allows us to compute realistic fiducial cross sections and assess the impact of fiducial cuts applied to the Higgs boson decay products on the magnitude of QCD radiative corrections in weak boson fusion.

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