Welcome

• Daniel Reichelt
• Luca Buonocore (CERN)
• Pier Francesco Monni (CERN)
• Alexander Karlberg (CERN)
• Alba Soto Ontoso (Universidad de Granada (ES))

Room: 500/1-001 - Main Auditorium

Current limitations of event generators in experimental analyses at the LHC

• Jennifer Roloff (Brown University (US))

Room: 500/1-001 - Main Auditorium

Conceptual and technical challenges in the matching of parton showers to higher-order calculations

• Peter Skands (Monash University (AU))

Room: 500/1-001 - Main Auditorium

LHC phenomenology with KrkNLO matching

• Andrzej Konrad Siodmok (Jagiellonian University (PL))

Room: 500/1-001 - Main Auditorium The systematic combination of perturbative QCD with parton-shower resummation is achieved at NLO by a small, but growing, number of 'NLO matching' methods. Among them, the KrkNLO method is unique in exploiting a modification of the PDF factorisation scheme, from the conventional $\overline{\mathrm{MS}}$ scheme, to a scheme (the 'Krk' scheme) in which the NLO corrections can be applied as a simple multiplicative reweight. This is positive by construction, since it does not use subtraction, and unlike other methods has no dependence on an unphysical choice of shower-scale or suppression factor. We summarise the KrkNLO method, its recent implementation for general colour-singlet processes in Herwig 7, and present results for LHC processes involving the production of massive and massless vector bosons. We will summarise the results of a systematic comparison with MC@NLO, and also review the properties of the Krk scheme among other factorisation schemes proposed as alternatives to $\overline{\mathrm{MS}}$, including their positivity.

Current status of NNLOPS simulations at LHC

• Luca Rottoli (Universita & INFN, Milano-Bicocca (IT))

Room: 500/1-001 - Main Auditorium

Logarithmically-accurate and positive-definite NLO shower matching with ESME

• Alexander Karlberg (CERN)

Room: 500/1-001 - Main Auditorium

NNLO matching in VINCIA

• Basem El-Menoufi

Room: 500/1-001 - Main Auditorium Fixed-order matching of Monte Carlo showers remains a critical ingredient to push forward the precision frontier of collider phenomenology. Beyond the conceptually simple leading-order matching, the past two decades have seen multiple techniques to achieve next-to-leading order (NLO) matching which have further been fully automated and made available in public codes. This pushed the precision frontier to NNLO. We outline a new technique to perform NNLO matching in which the shower Monte Carlo is used as the phase space generator. In the context of a simple process, Z decay to hadrons, we focus on the VINCIA sector shower which utilises the antenna formalism. In the sector approach, the phase space is partitioned into non-overlapping sectors which greatly simplifies the inclusion of 2->4 antenna functions. The matching formulae are derived by comparing the fully differential jet production cross section computed both in the shower and at fixed-order. We develop a technique to compute the complex sector integrals which control the NLO correction to the 3-jet production cross section. The latter is the only missing ingredient to achieve NNLO matching in the process Z decay to hadrons. Finally, we discuss the flowchart of the numerical implementation.

Final-state NLO matching in Alaric

• Peter Meinzinger (Zürich University)

Room: 500/1-001 - Main Auditorium In this talk, we present steps towards automated matching of the Alaric parton shower to NLO QCD matrix elements for lepton collisions in Sherpa. We validate our implementation against jet production in $e^+e^- \to$ jets for up to five jets. We show numerical tests of the subtraction in the infrared limit, benchmarking against the Catani-Seymour subtraction. We then present first hadron-level matched results compared against LEP data.

The Alaric project

• Stefan Hoeche (Fermilab)

Room: 4/3-006 - TH Conference Room

PanScales efforts towards NNLL showers

• Gregory Soyez (IPhT, CEA Saclay)

Room: 4/3-006 - TH Conference Room

Status of NLL-Accurate Parton Showers in Herwig

• Siddharth Sule (The University of Manchester (GB))

Room: 4/3-006 - TH Conference Room

Recent progress in subleading-colour effects and amplitude-level evolution

• Simon Platzer (University of Graz (AT))

Room: 4/3-006 - TH Conference Room

Hadronization models with NLL-accurate showers in Herwig

• Andre Hoang (Austrian Academy of Sciences (AT))

Room: 4/3-006 - TH Conference Room

Anomalous scaling of linear power corrections

• Silvia Zanoli (University of Oxford)

Room: 500/1-001 - Main Auditorium

Merging non-perturbative corrections in the two- and three-jet region

• Andrea Banfi (University of Sussex)

Room: 500/1-001 - Main Auditorium

A Precise Determination of $\alpha_s$ from Heavy Jet Mass

• Arindam Bhattacharya

Room: 500/1-001 - Main Auditorium A global fit for $\alpha_s(m_Z)$ is performed on available $e^+e^-$ data for the heavy jet mass distribution. The state-of-the-art theory prediction includes $\mathcal{O}(\alpha_s^3)$ fixed-order results, N$^3$LL$^\prime$ dijet resummation, N$^2$LL Sudakov shoulder resummation, and a first-principles treatment of power corrections in the dijet region. Theoretical correlations are incorporated through a flat random-scan covariance matrix. The global fit results in $0.1145^{+0.0021}_{-0.0019}$, compatible with similar determinations from thrust and $C$-parameter. Dijet resummation is essential for a robust fit, as it engenders insensitivity to the fit-range lower cutoff; without resummation the fit-range sensitivity is overwhelming. In addition, we find evidence for a negative power correction in the trijet region if and only if Sudakov shoulder resummation is included.

Recent developments in jet substructure calculations

• Simone Marzani (Università di Genova and INFN Sezione di Genova)

Room: 4/3-006 - TH Conference Room

Recent theoretical advancements in the description of energy correlations

• Huaxing Zhu (ZJU - Zhejiang University (CN))

Room: 4/3-006 - TH Conference Room

From Correlation Functions to Collider Observables: Unlocking Precision for Charge Dynamics in QCD

• Gherardo Vita

Room: 4/3-006 - TH Conference Room

Non-perturbative corrections to the projected N-point energy correlators

• Aditya Pathak (DESY)

Room: 4/3-006 - TH Conference Room

TH colloquium: The Strong Interaction at 50 Years: less Puzzling, more Rich, and still Mysterious

• Iain Stewart

Room: 500/1-001 - Main Auditorium https://indico.cern.ch/event/1513473/

Thrust distribution in electron-positron annihilation at full NNNLL+NNLO (and beyond) in QCD

• Giancarlo Ferrera (Università degli Studi e INFN Milano (IT))

Room: 500/1-001 - Main Auditorium

On Determining $\alpha_s(m_Z)$ from Dijets in $e^+e^-$ Thrust

• Miguel Benitez (University of Salamanca)

Room: 500/1-001 - Main Auditorium We update a previous N$^3$LL$^\prime$+${\cal O}(\alpha_s^3)$ determination of the strong coupling from a global fit to thrust data. Detailed discussions are provided concerning the stability of the results under variations of the fit range and the importance of summing up higher-order logarithmic terms for convergence and stability. We also demonstrate that a number of additional effects associated to power corrections have a small impact on this fit result, including modifications to the renormalon substraction scheme for dijet power corrections and the inclusion of three-jet power correction models.

Non-perturbative power corrections to $e^+e^-$ event shapes in the three-jet region and strong coupling fits

• Paolo Nason

Room: 500/1-001 - Main Auditorium

High-energy limit of QCD

• Einan Gardi

Room: 4/3-006 - TH Conference Room

All Orders Regge Factorization for Diffraction

• Iain Stewart

Room: 4/3-006 - TH Conference Room

Vector boson+dijets at large mjj

• Jeppe Andersen (IPPP, University of Durham)

Room: 4/3-006 - TH Conference Room We present the first calculation of high-energy corrections to the process of photon+dijet production. The high-energy corrections stabilise the fixed-order perturbative behaviour and lead to a significant improvement in the description of data.

Jet veto in $Q\bar{Q}X$ production at the LHC

• Luca Buonocore (CERN)

Room: 4/3-006 - TH Conference Room

Super-leading logarithms from effective field theory

• Thomas Georg Becher (Universitaet Bern (CH))

Room: 4/3-006 - TH Conference Room Factorization theorems for non-global observables at hadron colliders can be used to resum super-leading logarithms (SLLs) and we present a phenomenological analysis of their numerical impact in pp -> 2 jets. SLLs are closely related to collinear factorization breaking and are driven by a double-logarithmic evolution equation in an effective field theory. The compatibility of this double-logarithmic evolution with single-logarithmic PDF evolution at low scales implies stringent consistency conditions on the low-energy matrix element of this effective theory.  We will derive these conditions in our talk; the explicit computations necessary to verify consistency at the three-loop level will be covered in a separate presentation.

Differential threshold resummation for hadronic and SIDIS processes

• Stefano Forte (Università degli Studi e INFN Milano (IT))

Room: 500/1-001 - Main Auditorium Using renormalization group arguments in dQCD, I derive an analytic resummation formula for the threshold resummation of differential distributions with fixed longitudinal partonic kinematics. By matching to existing fixed-order NNLO computations I obtain NLL resummation for the Drell-Yan rapidity distribution with fixed partonic rapidity and for semi-inclusive deep-inelastic scattering. For Drell-Yan I compare to previous results obtained using SCET.

Overview of jet physics in heavy-ion collisions

• Joao Lourenco Henriques Barata

Room: 4/3-006 - TH Conference Room

Theoretical understanding of QCD cascades in heavy-ion collisions

• Guilherme Milhano (LIP-Lisbon & CERN TH)

Room: 4/3-006 - TH Conference Room

KNO scaling in quark and gluon jets at the LHC

• Lin CHEN (Instituto Galego de Fisica de Altas Enerxias - IGFAE)

Room: 4/3-006 - TH Conference Room The Koba-Nielsen-Olesen (KNO) scaling of hadron multiplicity distributions, empirically confirmed to hold approximately in $e^+e^-$ collisions and Deep Inelastic Scattering, has been observed to be violated in hadron-hadron collisions. In this work, we show that the universality of KNO scaling can be extended to hadron-hadron collisions when restricted to QCD jets. We present a comprehensive study of KNO scaling in QCD jets produced in proton-proton collisions at the LHC. Using perturbative QCD calculations in the double logarithmic approximation and PYTHIA simulations, we find that KNO scaling approximately holds for both quark and gluon jets across a broad jet $p_T$ range, from $0.1$ TeV to $2.5$ TeV, at both the parton and hadron levels. Especially, we highlight characteristic differences between the KNO scaling functions of quark and gluon jets, with the quark-jet scaling function lying above that of gluon jets at both low and high multiplicities. This distinction is essential for interpreting inclusive jet data at the LHC. Furthermore, we propose direct experimental tests of KNO scaling in QCD jets at the LHC through quark-gluon discrimination using jet substructure techniques, as demonstrated by applying energy correlation functions to PYTHIA-generated data.

Recent developments in the calculation of higher-order matrix-element in heavy-ion collisions

• Peter Arnold (University of Virginia (US))

Room: 4/3-006 - TH Conference Room

Farewell

• Pier Francesco Monni (CERN)
• Daniel Reichelt
• Alexander Karlberg (CERN)
• Alba Soto Ontoso (Universidad de Granada (ES))
• Luca Buonocore (CERN)

Room: 4/3-006 - TH Conference Room