Abstract We present the electroweak corrections for the production of a photon pair through gluon fusion, focusing on the contribution from the first two generations of quarks. The two-loop amplitude is calculated using a series of projection operators which define scalar form factors. In order to evaluate the Master Integrals which appear in this process we employ both generalized polylogarithms and Chen-iterated integrals. In order to perform a phenomenological study we develop a semi-numerical evaluation of the Master Integrals employing a fitting procedure to speed up the evaluation of burdensome higher weight contributions. We present results for the LHC, finding corrections of around a couple of percent to the leading order gg → γγ process. Our results are implemented into the parton-level Monte Carlo code MCFM.

Abstract We present next-to-leading order perturbative QCD predictions for four-jet-like event-shape observables in hadronic Higgs decays. To this end, we take into account two Higgs-decay categories: involving either the Yukawa-induced decay to a $${\text{b}}\overline{{\text{b}} }$$ pair or the loop-induced decay to two gluons via an effective Higgs-gluon-gluon coupling. We present results for distributions related to the event-shape variables thrust minor, light-hemisphere mass, narrow jet broadening, D-parameter, and Durham four-to-three-jet transition variable. For each of these observables we study the impact of higher-order corrections and compare their size and shape in the two Higgs-decay categories. We find large NLO corrections with a visible shape difference between the two decay modes, leading to a significant shift of the peak in distributions related to the H → gg decay mode.

Abstract We present a calculation of pseudoscalar Higgs production in association with a jet at Next-to-Next-to Leading Order (NNLO) accuracy in QCD. We work in an effective field theory in which mt → ∞ resulting in effective operators which couple the pseudoscalar to gluons and (massless) quarks. We have calculated all of the relevant amplitudes for the two-loop, one-loop and tree-level contributions. As a cross-check of our calculation we have re-calculated all of the scalar Higgs plus parton amplitudes and perform a detailed comparison to the literature. In order to regulate the infra-red singularities present at this order we employ the N-jettiness slicing method. In addition to a detailed validation of our calculation at this order we investigate LHC phenomenology for a selection of pseudoscalar Higgs masses. Our results are implemented into the parton-level Monte Carlo code MCFM.

We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these models to be further improved and systematic uncertainties to be reduced, directly contributing to future experimental success. Event generators are part of a much larger ecosystem of computational tools. They typically involve a number of unknown model parameters that must be tuned to experimental data, while maintaining the integrity of the underlying physics models. Making both these data, and the analyses with which they have been obtained accessible to future users is an essential aspect of open science and data preservation. It ensures the consistency of physics models across a variety of experiments.

This note documents predictions for the inclusive production cross sections of the Standard Model Higgs boson at the Large Hadron Collider at a centre of mass energy of 13.6 TeV. The predictions here are based on simple extrapolations of previously documented predictions published in the CERN Yellow Report "Deciphering the Nature of the Higgs Sector". The predictions documented in this note should serve as a reference while a more complete and update-to-date derivation of cross section predictions is in progress.

We present a calculation of the master integrals (MI’s) required for the calculation of the Electroweak corrections to gg→γγ production in which the process contains a light quark loop. The integrals can be broken down into five categories based on the flow of the heavy vector bosons throughout the loop. Three of the families are planar, and two are non-planar. We determine a canonical basis for each family which allows an efficient solution of the resulting differential equations via iterated integrals. We calculate the families in relevant physical kinematics and obtain an efficient numerical evaluation based on an implementation of Chen-iterated integrals.

The International Linear Collider (ILC) is on the table now as a new global energy-frontier accelerator laboratory taking data in the 2030s. The ILC addresses key questions for our current understanding of particle physics. It is based on a proven accelerator technology. Its experiments will challenge the Standard Model of particle physics and will provide a new window to look beyond it. This document brings the story of the ILC up to date, emphasizing its strong physics motivation, its readiness for construction, and the opportunity it presents to the US and the global particle physics community.

We present a next-to-next-to-leading order (NNLO) QCD calculation of the bottom-induced contributions to the production of a Higgs boson plus a jet, i.e. the process pp → H + j to 𝒪(y_b^2α_s^3) . We work in the five-flavor scheme (5FS) in which the bottom quark mass is retained only in the coupling to the Higgs boson. Our calculation uses N -jettiness slicing to regulate infrared divergences, allowing for fully-differential predictions for collider observables. After extensively validating the methodology, we present results for the 13 TeV LHC. Our NNLO predictions show a marked improvement in the overall renormalization and factorization scale dependence, the latter of which proves to be particularly troublesome for 5FS calculations at lower orders. In addition, using the same methodology we present a NNLO computation of bb → H . Our results are implemented into MCFM.

This corrects the article DOI: 10.1103/PhysRevLett.118.222001.

In this paper we present a fully-differential calculation for the contributions to the partial widths H → bb and H → cc that are sensitive to the top quark Yukawa coupling yt to order α3 s. These contributions first enter at order α2 s through terms proportional to ytyq (q = b, c). At order α3 s corrections to the mixed terms are present as well as a new contribution proportional to y2 t . Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b-tagging and c-tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H → cc channel, with effects as large as 15%. We show however that their impact can be significantly reduced by the application of jet-tagging selection cuts.

In this paper we present a fully-differential calculation for the contributions to the partial widths H -> bb<overbar></mml:mover> and H -> cc<mml:mo stretchy="true"><overbar></mml:mover> that are sensitive to the top quark Yukawa coupling y(t) to order alpha s3. These contributions first enter at order alpha s2 through terms proportional to y(t)y(q) (q = b, c). At order alpha s3 corrections to the mixed terms are present as well as a new contribution proportional to yt2. Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b-tagging and c-tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H -> c<mml:mover accent="true">c<mml:mo stretchy="true"><overbar></mml:mover> channel, with effects as large as 15%. We show however that their impact can be significantly reduced by the application of jet-tagging selection cuts.

In this paper we present a fully-differential calculation for the contributions to the partial widths H → bb and H → cc that are sensitive to the top quark Yukawa coupling y t to order α_s^3 . These contributions first enter at order α_s^2 through terms proportional to y t y q ( q = b, c ). At order α_s^3 corrections to the mixed terms are present as well as a new contribution proportional to y_t^2 . Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b -tagging and c -tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H → cc channel, with effects as large as 15

Abstract In this paper we present a fully-differential calculation for the contributions to the partial widths H →$$ b\overline{b} $$ b b ¯ and H →$$ c\overline{c} $$ c c ¯ that are sensitive to the top quark Yukawa coupling yt to order $$ {\alpha}_s^3 $$ α s 3 . These contributions first enter at order $$ {\alpha}_s^2 $$ α s 2 through terms proportional to ytyq (q = b, c). At order $$ {\alpha}_s^3 $$ α s 3 corrections to the mixed terms are present as well as a new contribution proportional to $$ {y}_t^2 $$ y t 2 . Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b-tagging and c-tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H →$$ c\overline{c} $$ c c ¯ channel, with effects as large as 15%. We show however that their impact can be significantly reduced by the application of jet-tagging selection cuts.

In this paper we present a fully-differential calculation for the contributions to the partial widths H→ bb̅ and H→ cc̅ that are sensitive to the top quark Yukawa coupling y_t to order α_s^3. These contributions first enter at order α_s^2 through terms proportional to y_t y_q (q=b,c). At order α_s^3 corrections to the mixed terms are present as well as a new contribution proportional to y_t^2. Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b-tagging and c-tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H→ cc̅ channel, with effects as large as 15 impact can be significantly reduced by the application of jet-tagging selection cuts.

In this paper we present a fully-differential calculation for the contributions to the partial widths H → $$ b\overline{b} $$ and H → $$ c\overline{c} $$ that are sensitive to the top quark Yukawa coupling yt to order $$ {\alpha}_s^3 $$ . These contributions first enter at order $$ {\alpha}_s^2 $$ through terms proportional to ytyq (q = b, c). At order $$ {\alpha}_s^3 $$ corrections to the mixed terms are present as well as a new contribution proportional to $$ {y}_t^2 $$ . Our results retain the mass of the final-state quarks throughout, while the top quark is integrated out resulting in an effective field theory (EFT). Our results are implemented into a Monte Carlo code allowing for the application of arbitrary final-state selection cuts. As an example we present differential distributions for observables in the Higgs boson rest frame using the Durham jet clustering algorithm. We find that the total impact of the top-induced (i.e. EFT) pieces is sensitive to the nature of the final-state cuts, particularly b-tagging and c-tagging requirements. For bottom quarks, the EFT pieces contribute to the total width (and differential distributions) at around the percent level. The impact is much bigger for the H → $$ c\overline{c} $$ channel, with effects as large as 15%. We show however that their impact can be significantly reduced by the application of jet-tagging selection cuts.

We present the calculation of the decay $$ H\to b\overline{b}j $$ at next-to-next-to-leading order (NNLO) accuracy in QCD. We treat the bottom quarks as massless with a non-zero Higgs Yukawa coupling yb. We consider contributions in which the Higgs boson couples directly to bottom quarks, i.e. our predictions are accurate to order $$ \mathcal{O}\left({\alpha}_s^3{y}_b^2\right) $$ . We calculate the various components needed to construct the NNLO contribution, including an independent calculation of the two-loop amplitudes. We compare our results for the two-loop amplitudes to an existing calculation finding agreement. We present additional checks on our two-loop expression using the known infrared factorization properties as the emitted gluon becomes soft or collinear. We use our results to construct a Monte Carlo implementation of $$ H\to b\overline{b}j $$ and present jet rates and differential distributions in the Higgs rest frame using the Durham jet algorithm.