We consider dijet production in $\textit{e}$ $\textit{e}$ collisions and in $$ H\to b\overline{b} $$ decays at next-to-next-to-leading order (NNLO) in perturbative QCD. A new non-local subtraction scheme is applied, for the first time, to obtain the fully differential cross section for these benchmark processes. We discuss and explicitly evaluate the perturbative ingredients needed in the computation, and we compare the performance of different slicing variables to obtain the NNLO corrections.

Switzerland

Luca Buonocore

Massimiliano Grazzini

Flavio Guadagni

Jürg Haag

Stefan Kallweit

Italy

Luca Rottoli

Jet production at NNLO: exploring a new scheme

The precise description of jet processes requires observables capable of efficiently capturing the dynamics of the energy flow in hadronic final states. We consider a class of transverse-momentum like resolution variables that smoothly describe the $$n+1$$ to $\textit{n}$ jet transition in multi-jet processes. We discuss a general method for the computation of the corresponding quark jet function at next-to-next-to-leading order in perturbative QCD. Rapidity divergences are regulated by using a time-like auxiliary vector. We present explicit results for a variant of $$y_{23}$$ in the $\textit{E}$-scheme and in the WTA scheme.

The quark jet function for $$k_T$$ -like variables in NNLO QCD

In this work we consider the QCD predictions for spin correlations in $$ t\overline{t} $$ production in hadronic collisions. In view of recent tensions between experimental data and theoretical calculations, it has been argued that one should include in the predictions also the effects of the production of the $\textit{η}$ , i.e. the pseudoscalar $$ t\overline{t} $$ bound state, or alternatively the full effects of the non-relativistic dynamics of the $$ t\overline{t} $$ pair near threshold. This implies the resummation of all corrections that scale like powers of $\textit{α}$ /$\textit{v}$ (where $\textit{v}$ is the velocity of the top quark in the $$ t\overline{t} $$ rest frame) which are dominated by values of $\textit{v}$ of order $\textit{α}$ . In this work, we show that, since the observables that are usually considered for these studies are integrated cross sections up to a $$ t\overline{t} $$ mass cut that is not small, it is possible to perform the calculation using perturbation theory, considering only the contributions that scale as the first few powers of $\textit{α}$ /$\textit{v}$. We examine the implications of our approach by computing corrections to nominal Monte Carlo results for correlation-sensitive observables, and compare them with available data, showing that the tension with data is no longer present.

Paolo Nason

Emanuele Re

Spin correlations in $$ t\overline{t} $$ production and decay at the LHC in QCD perturbation theory

We consider neutral- and charged-current Drell Yan lepton-pair production at hadron colliders, and include dominant classes of electroweak and mixed QCD-electroweak corrections to all orders in perturbation theory. The accurate description of these physical effects is vital for a precise determination of fundamental Standard Model parameters, such as the W-boson mass and the electroweak mixing angle, as well as for a solid assessment of the associated theoretical uncertainties. Our state-of-the-art resummation reaches next-to-leading-logarithmic accuracy in both the electroweak and the mixed QCD-electroweak perturbative expansions, including constant terms at first order beyond Born level in both couplings, i.e. at order α and α  s  α. These effects are incorporated on top of QCD predictions at next-to-next-to-next-to-leading-logarithmic accuracy, which include constant terms at third order in the strong coupling. Our results retain, for the first time at this accuracy, full dependence on the kinematics of the final-state leptons, thereby enabling a realistic comparison with experimental analyses at the differential level in presence of fiducial cuts. We present a phenomenological analysis of the impact of electroweak corrections in relevant observables at the LHC. We find visible shape distortions in resummation-dominated kinematical regions with respect to pure-QCD predictions, highlighting the importance of a complete description, not limited to QCD, for precision Drell Yan physics.

CERN

Paolo Torrielli

Resummation of combined QCD-electroweak effects in Drell Yan lepton-pair production

We present a new formulation of the MiNNLOPS method to match NNLO QCD calculations with parton showers by using jettiness as a resummation variable. The full derivation for colour-singlet processes is presented using 0-jettiness starting from the NNLL ′  resummation formula. We show phenomenological results for Drell-Yan and Higgs-boson production at the LHC and compare our predictions to ATLAS and CMS data. Differences to the original MiNNLOPS formulation using the transverse momentum of the colour singlet as resummation variable are discussed. We further present a comparison of MiNNLOPS predictions with Geneva. Finally, we extend the formulation of the MiNNLOPS method to 1-jettiness which is applicable to processes with a colour singlet plus one jet in the final state.

Germany

Markus Ebert

Marius Wiesemann

Giulia Zanderighi

United Kingdom

Silvia Zanoli

Jettiness formulation of the MiNNLOPS method

We consider subleading power corrections to event shape variables in  $$e^+e^-$$  <math> <mrow> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>-</mo> </msup> </mrow> </math>   collisions at the first order in the QCD coupling  $$\alpha _{\textrm{S}}$$  <math> <msub> <mi>α</mi> <mtext>S</mtext> </msub> </math>  . We start from the jettiness variable  $$\tau _2$$  <math> <msub> <mi>τ</mi> <mn>2</mn> </msub> </math>   and the  $$y_{23}$$  <math> <msub> <mi>y</mi> <mn>23</mn> </msub> </math>   resolution variable for the  $$k_T$$  <math> <msub> <mi>k</mi> <mi>T</mi> </msub> </math>   jet clustering algorithm and we analytically compute the corresponding cumulative cross section. We investigate the origin of the different power suppressed contributions in the two-jet limit and trace it back to their different coverage of the phase space. We extend our analysis to the case of thrust and of the C-parameter, and we finally discuss a class of observables that depend on a continuous parameter giving different weight to central and forward emissions and we evaluate the corresponding subleading power corrections.

Subleading power corrections for event shape variables in  $$e^+ e^-$$  <math> <mrow> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>-</mo> </msup> </mrow> </math>   annihilation

Scenarios with new physics particles feebly interacting with the Standard Model sector provide compelling candidates for dark matter searches. Geared with a set of new experiments for the detection of neutrinos and long-lived particles the Large Hadron Collider (LHC) has joined the hunt for these elusive states. On the theoretical side, this emerging physics program requires reliable estimates of the associated particle fluxes, in particular those arising from heavy hadron decays. In this work, we provide state-of-the-art QCD predictions for heavy hadron production including radiative corrections at next-to-leading order and using parton distribution functions including small-x resummation at next-to-leading logarithmic accuracy. We match our predictions to parton showers to provide a realistic description of hadronisation effects. We demonstrate the utility of our predictions by presenting the energy spectrum of neutrinos from charm hadron decays. Furthermore, we employ our predictions to estimate, for the first time, FASER’s sensitivity to electrophilic ALPs, which are predominantly generated in beauty hadron decays.

Felix Kling

Jonas Sominka

Predictions for neutrinos and new physics from forward heavy hadron production at the LHC

Poland

Wojciech Bizoń

Ulrich Haisch

United States

Zach Gillis

Brian Moser

Philipp Windischhofer

Addendum to: Constraints on the quartic Higgs self-coupling from double-Higgs production at future hadron colliders

Multiparton interactions are a fascinating phenomenon that occur in almost every high-energy hadron-hadron collision yet are remarkably difficult to study quantitatively. In this Letter, we present a strategy to optimally disentangle multiparton interactions from the primary scattering in a collision. That strategy enables probes of multiparton interactions that are significantly beyond the state of the art, including their characteristic momentum scale, the interconnection between primary and secondary scatters, and the pattern of three and potentially even more simultaneous hard scatterings. This opens a path to powerful new constraints on multiparton interactions for LHC phenomenology and to the investigation of their rich field-theoretical structure.

Jeppe R. Andersen

Pier Francesco Monni

Gavin P. Salam

Alba Soto-Ontoso

Exploring High-Purity Multiparton Scattering at Hadron Colliders

We consider the class of inclusive hadron collider processes in which one or more energetic jets are produced, possibly accompanied by colourless particles. We provide a general formulation of a slicing scheme for this class of processes, by identifying the various contributions that need to be computed up to next-to-leading order (NLO) in QCD perturbation theory. We focus on two novel observables, the one-jet resolution variable ∆E  t  and the n-jet resolution variable   <math> <msubsup> <mi>k</mi> <mi>T</mi> <mtext>ness</mtext> </msubsup> </math>  $$ {k}_T^{\textrm{ness}} $$ , and explicitly compute all the ingredients needed to carry out NLO computations using these variables. We contrast the behaviour of these variables when the slicing parameter becomes small. In the case of   <math> <msubsup> <mi>k</mi> <mi>T</mi> <mtext>ness</mtext> </msubsup> </math>  $$ {k}_T^{\textrm{ness}} $$  we also present results for the hadroproduction of multiple jets.

Chiara Savoini

Exploring slicing variables for jet processes