arXiv subjects

Rebecca von Kuk

Publications and source records attributed to Rebecca von Kuk.

7 recordsLinked to original sources

arXiv2026

Resumming transverse observables for NNLO+PS matching in GENEVA

We study the use of higher-order resummation for transverse observables to achieve NNLO+PS matching within the GENEVA framework. In particular, we embed $q_T$ resummation for colour-singlet production at N$^3$LL obtained via soft-collinear effective theory and implemented in the library SCETlib within GENEVA. We also study for the first time the use of the generalised $N$-jettiness variable in parton shower matching, and achieve the resummation of the one-jettiness defined with transverse measures up to NLL$'$ accuracy. As a case study, we use these resummed calculations to construct a GENEVA NNLO+PS generator for Higgs boson production in heavy-quark annihilation (with beauty or charm-quarks in the initial state). The use of transverse measures facilitates the matching to showers ordered in transverse momentum, and opens the door to possible future extensions of this approach to the production of colour singlets in association with final-state jets.

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arXiv2026

Resummation of Next-to-Leading Non-Global Logarithms in Higgs Production

We analyze Higgs production at the LHC with a jet veto at central rapidities and present the first next-to-leading logarithmic resummation of non-global logarithms for this process. The resummation combines one-loop hard and soft matching functions with two-loop anomalous dimensions in the large-$N_c$ limit. To perform the resummation we numerically solve renormalization group equations via the parton-shower framework MARZILI. After matching to fixed order, we perform a detailed study of different sources of uncertainties. We find that the hard matching corrections dominate by far and are substantially larger than in Drell-Yan production. Together with earlier results for Drell-Yan, these are the first resummations of subleading non-global logarithms in hadron-collider cross sections, and they provide a benchmark for logarithmically accurate parton showers.

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arXiv2026

Modelling $b\bar b H$ production for the LHC at 13.6 TeV

We present new state-of-the-art predictions for Standard Model Higgs boson production in association with a bottom-quark pair ($b\bar bH$). Updated cross sections are computed in accordance with the recommendations of the LHC Higgs Working Group, including the use of the PDF4LHC21 set of parton distribution functions, with a center-of-mass energy of 13.6 TeV. For the total inclusive cross section, we provide matched predictions of the massless five-flavour scheme and the massive four-flavour scheme at the fixed-order level. We further present recently obtained simulations matched to parton showers in both flavour schemes within the Standard Model, and also discuss them in the context of potential Beyond-the-Standard-Model scenarios. In the massless scheme, we compare different next-to-next-to-leading order predictions matched to parton showers obtained through the MiNNLOPS and GENEVA generators. In addition, the role of four-flavour scheme predictions is studied as a background to $HH$ searches, considering both the top-quark and bottom-quark Yukawa contributions to $b\bar bH$ production. Finally, we analyse the sensitivity of the Higgs transverse momentum spectrum to light-quark Yukawa couplings in the diphoton decay channel based on MiNNLOPS simulations.

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arXiv2025

Towards a Quantum Information Theory of Hadronization: Dihadron Fragmentation and Neutral Polarization in Heavy Baryons

We pioneer the application of quantum information theory to experimentally distinguish between classes of hadronization models. We adapt the CHSH inequality to the fragmentation of a single parton to hadron pairs, a violation of which would rule out classical dynamics of hadronization altogether. Furthermore, we apply and extend the theory of quantum contextuality and local quantum systems to the neutral polarization of a single spin-1 hadronic system, namely the light constituents of excited Sigma baryons $Σ^{*}_{c,b}$ formed in the fragmentation of heavy quarks.

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arXiv2025

Transverse Momentum-Dependent Heavy-Quark Fragmentation at Next-to-Leading Order

The transverse momentum-dependent fragmentation functions (TMD FFs) of heavy (bottom and charm) quarks, which we recently introduced, are universal building blocks that enter predictions for a large number of observables involving final-state heavy quarks or hadrons. They enable the extension of fixed-order subtraction schemes to quasi-collinear limits, and are of particular interest in their own right as probes of the nonperturbative dynamics of hadronization. In this paper we calculate all TMD FFs involving heavy quarks and the associated TMD matrix element in heavy-quark effective theory (HQET) to next-to-leading order in the strong interaction. Our results confirm the renormalization properties, large-mass, and small-mass consistency relations predicted in our earlier work. We also derive and confirm a prediction for the large-$z$ behavior of the heavy-quark TMD FF by extending, for the first time, the formalism of joint resummation to capture quark mass effects in heavy-quark fragmentation. Our final results in position space agree with those of a recent calculation by another group that used a highly orthogonal organization of singularities in the intermediate momentum-space steps, providing a strong independent cross check. As an immediate application, we present the complete quark mass dependence of the energy-energy correlator (EEC) in the back-to-back limit at $\mathcal{O}(α_s)$.

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arXiv2023

Transverse Momentum Distributions of Heavy Hadrons and Polarized Heavy Quarks

We initiate the study of transverse momentum-dependent (TMD) fragmentation functions for heavy quarks, demonstrate their factorization in terms of novel nonperturbative matrix elements in heavy-quark effective theory (HQET), and prove new TMD sum rules that arise from heavy-quark spin symmetry. We discuss the phenomenology of heavy-quark TMD FFs at $B$ factories and find that the Collins effect, in contrast to claims in the literature, is not parametrically suppressed by the heavy-quark mass. We further calculate all TMD parton distribution functions for the production of heavy quarks from polarized gluons within the nucleon and use our results to demonstrate the potential of the future EIC to resolve TMD heavy-quark fragmentation in semi-inclusive DIS, complementing the planned EIC program to use heavy quarks as probes of gluon distributions.

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arXiv2023

The $q_T$ spectrum for Higgs production via heavy quark annihilation at N$^3$LL$'$+aN$^3$LO

We study the transverse momentum ($q_T$) spectrum of the Higgs boson produced via the annihilation of heavy quarks ($s,c,b$) in proton-proton collisions. Using soft-collinear effective theory (SCET) and working in the five-flavour scheme, we provide predictions at three-loop order in resummed perturbation theory (N$^3$LL$'$). We match the resummed calculation to full fixed-order results at next-to-next-to-leading order (NNLO), and introduce a decorrelation method to enable a consistent matching to an approximate N$^3$LO (aN$^3$LO) result. Since the $b$-quark initiated process exhibits large nonsingular corrections, it requires special care in the matching procedure and estimation of associated theoretical uncertainties, which we discuss in detail. Our results constitute the most accurate predictions to date for these processes in the small $q_T$ region and could be used to improve the determination of Higgs Yukawa couplings from the shape of the measured Higgs $q_T$ spectrum.

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