arXiv subjects

Terry Generet

Publications and source records attributed to Terry Generet.

16 recordsLinked to original sources

arXiv2026

Energy Correlators in $V + X$ as a Benchmark Observable for Precision QCD

We propose projected energy correlators measured on the recoiling QCD radiation of a $Z/\gamma$ as a benchmark observable for precision QCD at the LHC. Using the $Z/\gamma$ as a hard scale prevents the need for a jet algorithm, simplifying both the perturbative and non-perturbative corrections. We develop a framework to combine state-of-the-art fixed-order amplitudes, high order resummation, and universal non-perturbative matrix elements. Our approach is based on numerically computed inclusive hard functions, allowing flexibility in the process and the inclusion of realistic experimental cuts. We perform detailed numerical studies of the projected energy correlators at next-to-leading order + next-to-next-to-leading logarithm (NLO+NNLL) to verify the stability of our setup. We present numerical results at NLO+NNLL, which are the first complete matched predictions for energy correlators at the LHC at this order. We discuss the prospects for extensions to higher orders, outlining a path to NNLO calculations of energy correlators at the LHC.

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arXiv2026

Top-associated Higgs-boson production using perturbative fragmentation functions at next-to-leading-order

Under certain conditions, the production of a Higgs boson in association with a top-anti-top pair at hadron colliders can be described via a factorisation theorem using perturbative fragmentation functions. The latter describe the nearly collinear emission of a Higgs boson from a top-quark and reproduce the leading mass dependence of the exact next-to-leading-order (NLO) calculation. Although the NLO fragmentation functions have been calculated a few years ago, it has not been possible up to now to demonstrate the applicability of the approximation in a realistic setup. At NLO, we analyse two different ways of treating the top-quark mass, called the zero-mass-top-quark (ZMTQ) and the hybrid prescription. We show that the method yields reliable results at LHC center-of-mass (cms) energies in the hybrid prescription. In the ZMTQ prescription, the results at LHC cms energies are only reliable in the quark-anti-quark channel, but become viable for the full $pp \rightarrow t\bar{t}H$ process at a 100 TeV hadron collider. In addition, we discuss some subtleties and complications arising when extending the formalism to next-to-next-to-leading-order (NNLO) and beyond.

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arXiv2026

Les Houches study on inclusive jet production at NNLO+NNLL

Jet production at the LHC is a powerful probe of QCD, making it ideal for precision tests and determinations of QCD parameters such as parton distribution functions and the strong coupling constant. To make the most of the abundant jet production data collected at the LHC, precise calculations are required. While state-of-the-art calculations reach next-to-next-to-leading order (NNLO) QCD accuracy, a critical assessment of the remaining uncertainties arising from non-perturbative effects and missing higher orders remains crucial for correctly interpreting comparisons between theory and data. Scale variation is nearly always used to determine effects from missing higher orders. In this article, we reassess this method in the context of inclusive jet production by performing NNLO QCD calculations supplemented by small-jet-radius resummation through next-to-next-to-leading-logarithmic accuracy (NNLL). We find that NNLL resummation can have an appreciable impact on the scale uncertainty for inclusive jet cross sections, and, for some scale choices, can lead to sizeable shifts of the central cross section. We conclude that scale variations in fixed-order and resummed calculations can drastically underestimate the impact of higher orders for commonly used jet radius parameters, and that missing higher-order estimates obtained via scale variations should be considered unreliable. Our findings add further evidence to the importance of going beyond scale variations in jet and jet substructure calculations.

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arXiv2026

Next-to-next-to-next-to-leading order QCD corrections to photon-pair production

The production of two isolated photons in high-energy hadron collisions poses a challenge to perturbative QCD because of large corrections through next-to-next-to-leading order (NNLO). We present novel next-to-next-to-next-to-leading order ($\text{N}^3$LO) predictions and finally demonstrate perturbative convergence for this process. We discuss the considerable computational challenges and phenomenological results for the Large Hadron Collider.

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arXiv2025

IRC-safe jet flavour at leading power

We derive the leading power quark mass effects in cross sections involving flavour modulo-2 jets at next-to-next-to-leading order (NNLO) in QCD. Including these leading power terms recovers, up to power corrections, the infrared-collinear-safe massive-quark cross section from the infrared-collinear-unsafe massless-quark one. The method is applicable to all common jet algorithms and significantly more practical than computing fully massive cross sections. We explicitly demonstrate the approach for flavoured jets produced in lepton collisions, inclusive $b$-jet production at the LHC and the associated production of a $b$-jet and a $Z$-boson at the LHC. Through NNLO, we do not observe any breakdown of perturbative convergence resulting from the presence of logarithms of the quark mass, though such effects might become significant at higher orders. The most important feature of our approach is that it does not require any changes to the definition of the jet or its flavour, nor does it modify the definition of the cross section. Consequently, the predictions can be compared to measurements performed using standard jet clustering algorithms, provided that jet flavour is assigned according to the flavour modulo-2 scheme or an unfolding to this scheme is performed, without the need for experimental collaborations to adapt their analyses to some new, infrared-collinear-safe definition of jet flavour, as would be the case for most - if not all - solutions presented in the literature thus far. We further demonstrate that power corrections in the quark mass, which are typically neglected in the literature, can be significant.

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arXiv2025

Associated production of a $W$-boson and a charm meson at NNLO in QCD

The production of heavy-flavor hadrons in association with a vector boson in proton-proton collisions is a powerful probe for studying Quantum Chromodynamics and the content of protons. In this article, we provide, for the first time, differential predictions through NNLO for the production of $W^{\pm}D^{(*)\mp}$ final states. The results are compared to recent ATLAS measurements, and the sensitivity to the strange content of the proton is investigated by PDF profiling. The results are found to be promising for including $W^{\pm}D^{(*)\mp}$ measurements in proton-proton collisions in PDF fits.

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arXiv2025

Correlator with tensor currents and two masses at two loops

We calculate the vacuum-to-vacuum correlator of two quark tensor currents with two massive quarks, retaining full momentum dependence. For the first time, we include perturbative corrections up to next-to-leading order. Our fully analytical expressions are provided in machine-readable form. Furthermore, we present numerical results for various input parameters, including an estimate of the scale uncertainties. Our results are essential input for applications of dispersive methods, including unitarity bounds and QCD sum rules.

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arXiv2025

Small radius inclusive jet production at the LHC through NNLO+NNLL

The study of hadronic jets and their substructure at hadronic colliders is crucial for improving our understanding of QCD, and searching for new physics. As such, there has been a significant effort to improve their theoretical description. In the small radius limit, inclusive jet production exhibits a universal factorization, enabling the resummation of logarithms which greatly stabilizes theoretical predictions. In this paper, we show how to combine a recently introduced framework for small-$R$ resummation with the STRIPPER subtraction formalism for fragmentation, enabling next-to-next-to-leading order calculations of small-$R$ inclusive jet production for a wide variety of processes at the LHC. We extract the two-loop constants for the jet functions, enabling for the first time next-to-next-to-leading logarithmic resummation matched to next-to-next-to-leading order perturbative calculation. We compare with CMS data for small-$R$ jet production, and find that our results greatly improve the accuracy of the predictions at small-$R$, and stabilize the perturbative convergence and error estimates at larger $R$. Our approach is applicable to a wide class of jet substructure observables exhibiting similar factorization theorems, opening the door to an NNLO jet substructure program at the LHC.

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arXiv2025

Identified Hadron Production at Hadron Colliders in Next-to-Next-to-Leading-Order QCD

In this work we calculate for the first time the next-to-next-to leading order (NNLO) QCD corrections to identified hadron production at hadron colliders. The inclusion of the NNLO correction has an important impact on all observables considered in this work. Higher order corrections reduce scale uncertainty and in almost all cases are moderate. Overall, good perturbative convergence is observed across kinematics and observables. The uncertainty due to missing higher orders is relatively small and, in many cases, smaller than the experimental uncertainty. The largest source of theoretical uncertainty at present is from the knowledge of the non-perturbative parton-to-hadron fragmentation functions (FF), which dwarfs the scale uncertainty in most kinematic ranges. The inclusion of NNLO corrections demonstrates the precision studies potential of this class of observables. To fully realize this potential, however, a new generation of improved fragmentation functions may be needed. The results of the present work will enable global fits of FF with NNLO precision.

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arXiv2024

Open $B$-hadron production at hadron colliders in QCD at next-to-next-to-leading-order and next-to-next-to-leading-logarithmic accuracy

We report on a calculation of open heavy-flavor production at hadron colliders which extends to next-to-next-to-leading order (NNLO) accuracy the classic NLO-accurate formalism developed almost 30 years ago under the acronym FONLL. The approach retains the exact heavy-flavor mass dependence at low transverse momentum, $p_T$, and resums collinear logarithms through next-to-next-to-leading log (NNLL) at high $p_T$. Provided are predictions for $B$-hadrons as well as $B$-decay products like $J/\Psi$ and muons. The main features of the NNLO+NNLL results are reduced scale dependence and moderate NNLO correction, consistent with perturbative convergence in a wide range of kinematic scales from few GeV up to asymptotically large values of $p_T$. The new calculation significantly improves the agreement with data for $B$-hadrons and muons. We uncover an intriguing discrepancy in $J/\Psi$ final states which may point to a lower value of the $B\to J/\Psi$ decay rate.

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arXiv2024

Open bottom production at NNLO+NNLL

In this talk, I presented some of the results of the first calculation of open bottom production at hadron colliders at NNLO+NNLL, i.e. a next-to-next-to-leading-order calculation that resums collinear logarithms at next-to-next-to-leading-logarithmic accuracy. This new computation achieves significantly reduced theory errors compared to previous calculations, with errors of just a few percent at high transverse momenta. These results are compared to data from many measurements performed at the Tevatron, where lower-order predictions have previously been found to underestimate the cross section. To perform such comparisons, the hadronisation and decay of the $b$-quark are included in the theory calculation where needed, yielding predictions for a wide range of final states.

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arXiv2023

NNLO B-fragmentation fits and their application to $t\bar t$ production and decay at the LHC

In this work we derive three sets of non-perturbative fragmentation functions, with uncertainties, for $B$-hadrons, $J/ψ$'s and muons resulting from semileptonic $B$ decays. All three sets are with next-to-next-to leading order accuracy and include next-to-next-to leading logarithmic soft gluon resummation. The novel feature of these new sets is that they are fully consistent with our formalism for next-to-next-to leading order (NNLO) calculations for final states with identified $B$, $J/ψ$ or a $μ$. We employ the fragmentation functions derived in this work to make state of the art predictions for such final states in $t\bar t$ events at the LHC. A special emphasis is placed on observables sensitive to the top quark mass. The present work opens the door for many LHC applications, like, open $B$ production or $B$ production in association with bosons.

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arXiv2022

Top-pair events with B-hadrons at the LHC

The first implementation of fragmentation in a numerical code for the computation of cross sections at next-to-next-to-leading order in QCD has recently been completed. I will present some results of the first application of this new framework to the production of top-quark pairs at the LHC in association with a bottom-flavoured hadron. Additionally, I will present an extended version of this calculation, which includes the decay of the $B$-hadron to a $J/ψ$ meson or a muon.

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arXiv2021

Top-pair events with B-hadrons at the LHC

In these proceedings, we summarise the results of the recent calculation of the NNLO QCD corrections for the production of a top-quark pair in association with a bottom-flavoured hadron. The results consist of differential distributions of observables involving the identified hadron.

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arXiv2021

Higgs-boson production in top-quark fragmentation

We compute the fragmentation functions for the production of a Higgs boson at $\mathcal{O}(y_t^2α_s)$. As part of this calculation, the relevant splitting functions are also derived at the same perturbative order. Our results can be used to compute differential cross sections with arbitrary top-quark and Higgs-boson masses from massless calculations. They can also be used to resum logarithms of the form $\ln(p_T/m)$ at large transverse momentum $p_T$ to next-to-leading-logarithmic accuracy by solving the DGLAP equations.

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arXiv2021

B-hadron hadro-production in NNLO QCD: application to LHC $t\bar{t}$ events with leptonic decays

We calculate, for the first time, the NNLO QCD corrections to identified heavy hadron production at hadron colliders. The calculation is based on a flexible numeric framework which allows the calculation of any distribution of a single identified heavy hadron plus jets and non-QCD particles. As a first application we provide NNLO QCD predictions for several differential distributions of $B$ hadrons in $t\bar t$ events at the LHC. Among others, these predictions are needed for the precise determination of the top quark mass. The extension of our results to other processes, like open or associated $B$ and charm production is straightforward. We also explore the prospects for extracting heavy flavor fragmentation functions from LHC data.

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