Higgs 2025

27 Oct 2025, 09:00 → 31 Oct 2025, 19:00 US/Eastern

Brown University

Gaetano Barone (Brown University), Loukas Gouskos (Brown University (US))

 

This year's annual HIGGS conference takes place at Brown University on October 27th-31st.

 

The HIGGS 2025 conference features the latest results from the Large Hadron Collider experiments on measurements of the Higgs boson properties, on Higgs boson pair production, and searches for new physics in the scalar sector. The most recent theoretical developments in the Higgs sector, both in and beyond the Standard Model, are also a significant component of the scientific program of HIGGS 2025.

The conference provides an opportunity for critical discussions of the current strategies for studying the Higgs boson, searching for new physics in the Higgs sector at the LHC, and the next steps beyond the LHC. HIGGS 2025 includes several sessions of parallel and plenary contributions on the current research topics related to the Higgs sector.

Monday 27 October

Plenary: 20 Washington Place

Main Auditorium, 20 Washington Place

1 Welcome

2 Current big questions Higgs & EWK physics

Speaker: John Alison (Carnegie-Mellon University (US))

3 CMS Highlights

Speaker: Matteo Bonanomi (Hamburg University)

4 ATLAS Highlights

Speaker: Giovanni Marchiori (APC, CNRS/IN2P3 and Université Paris Cité)

5 LHCb Highlights

Speaker: Nathan Grieser (University of Cincinnati (US))

15:00 Coffe/Tea

Plenary

Main Auditorium, 20 Washington Place

6 New developments in Monte Carlo

Speaker: Max Knobbe (Fermilab)

7 Di-Higgs production overview

Speaker: Tania Robens (Rudjer Boskovic Institute (HR))

robens_higgs25.pdf

8 The connection between Higgs and flavour

Speaker: Marko Pesut (University of Zürich)

9 aN3LO PDFs and impact on Higgs predictions

Speaker: Giacomo Magni (Université Paris-Saclay (FR))

Welcome reception: 20 Washington Place

Tuesday 28 October

Beyond the Standard Model Higgs

Talks are 20' (presentation) + 5' (discussion)

Parallel room, 20 Washington Place

Conveners: Ennio Salvioni (UAB and IFAE, Barcelona), Jingyu Luo (Brown University), Nathan Grieser (University of Cincinnati), Tatjana Lenz (University of Bonn)

10 Two-Component Dark Matter in a $U(1)_X$ Extended Scalar Sector with an Inert Doublet

We investigate an extension of the Standard Model featuring a local $U(1)_X$ gauge symmetry, an additional complex scalar singlet, and two scalar doublets, one of which is inert. The scalar sector consists of an active doublet responsible for electroweak symmetry breaking, an inert doublet that yields a scalar Dark Matter candidate, and a singlet scalar whose vacuum expectation value spontaneously breaks $U(1)_X$. A neutral fermion $\chi$, charged under $U(1)_X$ and even with respect to an imposed $\mathbb{Z}_2$ symmetry, serves as a second, fermionic Dark Matter candidate. The inert doublet is $\mathbb{Z}_2$-odd, ensuring the stability of the scalar dark matter component.

We analyze the scalar and gauge boson mass spectra after spontaneous symmetry breaking, accounting for kinetic mixing and neutral gauge boson mixing. The interactions relevant for Dark Matter annihilation and direct detection are derived, and we examine the relic abundance within a two-component dark matter framework. Both the fermion $\chi$ and the inert scalar can reproduce the observed relic density in complementary regions of parameter space, consistent with current experimental bounds. This framework offers a rich phenomenology, connecting extended gauge dynamics, scalar sector structure, and dark matter physics.

Speaker: José Halim Montes de Oca Yemha (FESC-UNAM)

11 Search results for low-mass new scalars and Higgs decays to BSM

The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable of explaining some observations by itself. Many extensions of the Standard Model addressing such shortcomings introduce beyond-the-Standard-Model couplings to the Higgs boson. In this talk, the latest searches in the Higgs sector are reported, with emphasis on the results obtained with the full LHC Run 2 dataset at 13 TeV and including a series of searches for low-mass resonances in merged or boosted topologies.

Speaker: G Shani Nimeshika Perera (University of Massachusetts)

12 Accommodating scalars below 125 GeV with two Higgs doublets

The tantalising prospect that hints of scalars lighter than the 125 GeV Higgs boson may have already shown themselves at the LEP and LHC or will, at least, emerge during the run of the upcoming generation of colliders, has brought a renewed interest into scalar sectors with fields beyond the Standard Model. The addition of a second Higgs doublet stands as one of the simplest possible extensions, whose augmented parameter space, while opening the window to solutions to a few of the shortcomings of the current theory and to a plethora of new phenomena to be discovered, also comes with problems of its own: significant among those, the introduction of flavour-changing neutral currents at tree-level. These can be tackled with the imposition of specific Z2 symmetries on the model or, alternatively, by demanding the alignment of Yukawa couplings in flavour space, so that the diagonalisation of mass terms trims non-diagonal couplings of fermions with the additional neutral scalars as well. Setting out to ascertain whether current data allows two-Higgs-doublet models to accommodate low-mass scalars, we present here the results of new state-of-the-art global fits. Our numerical analyses make use of purely theoretical constraints, bounds from direct searches for neutral and charged scalars at the LEP and LHC, the signal strengths of the Higgs boson measured at the LHC, electroweak precision observables, and a set of flavour observables, all globally combined within HEPfit, a software with a Bayesian Markov Chain Monte Carlo approach to statistical inference.

Speaker: Antonio Coutinho (IFIC, U. Valencia - CSIC)

Single Higgs measurements and calculations: Session 1

Talks are 17' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Clara Lavinia Del Pio (Brookhaven National Lab), Emanuele Di Marco (INFN, Roma 1 (IT)), Hannah Arnold (Stony Brook University)

13 Measurements of the Higgs boson mass and width with the ATLAS detector

This talk presents recent precision measurements of key properties of the Higgs boson using the full dataset of proton-proton collisions at √s = 13 TeV collected during Run 2 of the LHC by the ATLAS experiment. The Higgs boson mass is determined with high accuracy through its decays into two photons and four leptons, and the adopted analysis strategies and experimental techniques will be discussed in detail, highlighting their impact on the measurement. In addition, the talk will cover indirect determinations of the Higgs boson total width, an essential parameter for understanding the Higgs sector. While the width is too small to be directly measured at the LHC, constraints are obtained via off-shell Higgs production in ZZ and WW final states, through the 4top final state, and through interference effects in the diphoton channel. The results represent the most up-to-date measurements from ATLAS and provide important insights into Higgs boson properties.

Speaker: Carolina De Almeida Rossi (University of Toronto (CA))

14 Measurement of Higgs boson mass and width with on-shell and off-shell productions with CMS

An important aspect of the Higgs boson is its width–the quantity related to its lifetime and energy spectrum. Methods for measuring the Higgs boson total decay width from the off-shell to on-shell signal strength ratio will be presented for the decays of H→WW→2l2ν, H→ZZ→2l2ν, and H→ZZ→4l.
Measurement of the Higgs boson width from the on-shell peak using the H->γγ final state will be presented using the Run2 data collected by the CMS experiment. The Higgs width is constrained using CMS data collected between 2016 and 2018, corresponding to a total integrated luminosity of 138 fb−1.

Speaker: Pedro Fernandez Manteca (CERN)

15 Theoretical modeling of QCD radiation in off-shell Higgs production through gluon fusion

The measurement of the Higgs boson width is a critical test of the Standard Model, with significant implications for understanding electroweak symmetry breaking. Direct measurements are limited by detector resolution, but it can be measured with greater precision through a combined analysis of on-shell and off-shell Higgs boson production. While results for on-shell production have been computed to a very high accuracy, theoretical predictions for off-shell Higgs boson production are not as well controlled due to the breakdown of the heavy-top approximation and the large interference with non-resonant amplitudes. Seeking to understand and improve the theoretical control, we compare leading-order and next-to-leading-order plus parton shower differential cross-sections for signal, background, and full physical processes in off-shell Higgs boson production at the Large Hadron Collider, using PowHeg, MadGraph, and Sherpa. We analyze the impact of higher-order quantum chromodynamics effects and theoretical uncertainties, highlighting differences between predictions using jet merging with parton showers, and those from next-to-leading order computations matched to parton showers. The results provide insights for improving theoretical predictions and their application to experimental measurements in the future.

Speaker: Rafael Coelho Lopes De Sa (University of Massachusetts (US))

16 Measurements of Higgs Boson Production and Properties Through Decays into Boson Pairs with the ATLAS Detector

Decays of the Higgs boson into pairs of bosons offer some of the most precise avenues for measuring its production cross sections and probing its fundamental properties. This talk presents the latest cross section measurements by the ATLAS experiment in bosonic decay channels, based on proton-proton collision data collected at sqrt(s) =13 TeV during Run 2 of the LHC, with the inclusion of available Run 3 results where relevant. Interpretations of these measurements in the context of Standard Model effective field theories (SMEFT) will also be discussed, providing a framework to probe potential deviations from Standard Model predictions.

Speaker: Chiara Arcangeletti (INFN e Laboratori Nazionali di Frascati (IT))

10:30 Break

Beyond the Standard Model Higgs

Talks are 20' (presentation) + 5' (discussion)

Parallel room, 20 Washington Place

Single Higgs measurements and calculations: Session 2

Talks are 17' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Clara Lavinia Del Pio (Brookhaven National Lab), Emanuele Di Marco (INFN, Roma 1 (IT)), Hannah Arnold (Stony Brook University)

17 Measurements of the CP structure of Higgs-boson couplings with the ATLAS detector

The Standard Model predicts the Higgs boson to be a CP-even scalar, but CP-odd contributions to its interactions with vector bosons and quarks are not yet strongly constrained. Various Higgs boson production and decay processes provide valuable tools to investigate the CP nature of these interactions. This talk presents the most recent measurements of the CP properties of Higgs boson interactions with vector bosons, performed by the ATLAS experiment using proton-proton collision data collected at sqrt(s) =13 TeV. These results offer important constraints on possible CP-violating effects, advancing our understanding of Higgs boson dynamics.

Speaker: Simen Hellesund (University of Bergen (NO))

18 Anomalous coupling and EFT measurement at CMS

Effective Field Theories and anomalous couplings including CP violation provide interesting ways to parameterize indirect BSM physics, when its characteristic scale is larger than the one directly accessible at the LHC, for a large class of models. Constraints on such effects derived by measurements of several production and decay modes of the Higgs boson and their combination on the data set collected by the CMS experiment will be presented.

Speaker: Nick Smith (Fermi National Accelerator Lab. (US))

19 Study of spin correlations in H->4l at CMS

Kinematic effects in the Higgs boson decay to four leptons are investigated using full detector simulation combined with matrix element techniques. The analysis is optimized to enhance sensitivity to the tensor structure of Higgs boson interactions and the spin correlations present in the decay process. The study is based on data collected by the CMS experiment at the LHC. The interactions of the Higgs boson with electroweak vector bosons are studied through an effective Lagrangian framework, and the results are presented as constraints on parameters that extend beyond the Standard Model.

Speaker: Jeffrey Davis (Johns Hopkins University (US))

12:30 Lunch

Higgs Potential, Di-Higgs, and Multi-Higgs

Talks are 20' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Dr Andreas Papaefstathiou (Kennesaw State University, GA, USA), Liza Brost (Brookhaven National Laboratory (US)), Marina Kolosova (University of Florida (US)), William Balunas (University of Oxford (GB))

20 Non-Resonant Higgs Boson Pair Production and Self-Coupling Measurements with the ATLAS Experiment

Higgs boson pair production (HH) plays a central role in probing the Higgs boson self-interactions, which are key to understanding the shape of the Higgs potential and the mechanism of electroweak symmetry breaking. This talk presents the latest results from the ATLAS experiment on non-resonant Higgs boson pair production, based on the full Run 2 dataset collected at\sqrt{s} = 13 TeV, with the inclusion of available Run 3 results where available. These analyses provide sensitivity to the Higgs boson self-coupling and the quartic VVHH coupling, offering key tests of the Higgs sector beyond single-Higgs measurements. Constraints are also derived from higher-order electroweak corrections to single Higgs boson production, and a combination of single and di-Higgs results is used to obtain the most precise determination of the self-coupling to date.

Speaker: Alexandra Claire Sidley (Nikhef National institute for subatomic physics (NL))

21 Non-resonant double Higgs combination at CMS

A basic research goal of high energy physicists is to shed light on the reality of the Higgs mechanism through the study of the Higgs potential. Indeed an important test of the Standard Model is a determination of the form of the Higgs potential and the Higgs field self-coupling. The trilinear self-coupling can be extracted from the measurement of non-resonant Higgs boson pair (HH) production. A measurement of the self-coupling will not be feasible with the data collected during Run 2, but only with the full data set of the HL-LHC. Nevertheless, useful upper limits on the production cross section could be obtained. And, of course, there is always the possibility of a deviation from the Standard Model prediction, which would be an unambiguous sign of new physics at the TeV scale. Recent results for non-resonant HH analyses combination will be presented and interpreted within the SM and BSM theories.

Speaker: Nicola De Filippis (Politecnico/INFN Bari (IT))

22 Understanding and reducing top-mass scheme uncertainty in Higgs pair production at high-energy

Precise predictions for double Higgs production are essential to probe the Higgs self-coupling at future colliders. A major source of theoretical uncertainty arises from the choice of the top-quark mass renormalization scheme, which strongly affects the predicted cross sections at high energy. In my talk, I will discuss the origin of these uncertainties and show that the mass effects follow a systematic, factorised pattern. This structure allows us to resum the dominant logarithmic contributions and substantially reduce the scheme dependence. The improved predictions provide a more reliable baseline for experimental studies of Higgs pair production and enhance the sensitivity to deviations from the Standard Model.

Speaker: Robert Szafron (Brookhaven National Laboratory)

Higgs Physics at Future Colliders

Talks are 17' (presentation) + 5' (discussion)
Parallel room, 20 Washington Place

Conveners: Carissa Joyce Cesarotti, Kiley Elizabeth Kennedy (Princeton University (US)), Lindsey Gray (Fermi National Accelerator Lab. (US)), Marc-Andre Pleier (Brookhaven National Laboratory (US))

23 Impact of Detector Design on Flavor Tagging and Higgs Measurements at FCC-ee

The extensive and ambitious physics program planned for the Future Circular Collider for electrons and positrons (FCC-ee) demands exceptional detector performance. This talk systematically investigates how different detector configurations impact jet flavor identification and their effects on high-profile physics analyses. Using Higgs boson coupling measurements and searches for invisible Higgs decays as benchmarks, we evaluate the sensitivity of these analyses to variations in tracker and calorimeter detector properties. We examine modifications to single-point resolution, material budget, silicon layer placement, and particle identification capabilities, quantifying their effects on flavor-tagging performance. Additionally, we present the first comprehensive study of Higgs-to-invisible decay detection using full detector simulation, providing crucial insights for optimizing future detector designs at lepton colliders.

Speaker: Iza Veliscek (Brookhaven National Laboratory (US))

24 Prospects for di-Higgs measurements at the HL-LHC with the ATLAS experiment

The High-Luminosity LHC (HL-LHC) is expected to deliver an integrated dataset of approximately 3 ab⁻¹, enabling detailed studies of Higgs boson processes with unprecedented precision. Projections based on current analyses have been performed to estimate the expected measurement accuracy and identify potential limitations. The large data sample will also significantly enhance sensitivity to di-Higgs production, providing access to the Higgs boson self-coupling. This talk will present the ATLAS experiment’s prospects for di-Higgs measurements at the HL-LHC.

Speaker: Daniela Bortoletto (University of Oxford (GB))

25 Prospects for di-Higgs measurements at the HL-LHC with the CMS experiment

The title says it all

Speaker: Alexandra Carvalho Antunes De Oliveira (Peking University (CN))

15:00 Break

Higgs Potential, Di-Higgs, and Multi-Higgs

Talks are 20' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Andreas Papaefstathiou (Kennesaw State University (US)), Liza Brost (Brookhaven National Laboratory (US)), Marina Kolosova (University of Florida (US)), William Balunas (University of Oxford (GB))

26 Search for HH production in the bbγγ final state with the CMS detector

The most recent results from the CMS collaboration on measurements of non-resonant HH production using bbγγ final states and their combination using the data set collected by the CMS experiment at a centre of mass energy of 13.6 TeV will be presented

Speaker: Angela Taliercio (Northwestern University (US))

27 Search for non-resonant HH production in the bbγγ final state with the ATLAS detector

A direct probe of the Higgs boson trilinear self-coupling is possible via Higgs boson pair production, making di-Higgs analyses particularly interesting. In addition, HH production via vector boson fusion, the second-leading HH production process, has a unique sensitivity to the interaction between two Higgs bosons and two vector bosons. Furthermore, enhancements to the di-Higgs production rate would point to new physics beyond the Standard Model, making such analyses interesting at the LHC This talks presents a search for non-resonant production of Higgs boson pair in the two bottom quarks plus two photons final state using the full Run 2 dataset and partial Run 3 dataset. EFT interpretations are also discussed.

Speaker: Punit Sharma (Brookhaven National Laboratory (US))

28 Improved measurement of di-Higgs production in the 4b final state with Run-3 data from the CMS Detector

We present improved measurement of HH→4b production cross section from Run 3 CMS data collected in 2022 and 2023, covering both resolved and merged topologies. We highlight the recent advancements and novel techniques to significantly enhance the analysis sensitivity.

Speaker: Soumya Mukherjee (Univ. of California San Diego (US))

29 Search for non-resonant HH production in the 4b final state with the ATLAS detector

A direct probe of the Higgs boson trilinear self-coupling is possible via Higgs boson pair production, making di-Higgs analyses particularly interesting. In addition, HH production via vector boson fusion, the second-leading HH production process, has a unique sensitivity to the interaction between two Higgs bosons and two vector bosons. Furthermore, enhancements to the di-Higgs production rate would point to new physics beyond the Standard Model, making such analyses interesting at the LHC. This talks presents a search for non-resonant production of Higgs boson pair in the 4 bottom quarks final state using the full Run 2 dataset.

Speaker: Nicholas Luongo (Argonne National Laboratory (US))

Higgs Physics at Future Colliders

Talks are 17' (presentation) + 5' (discussion)
Parallel room, 20 Washington Place

30 What can we learn from Higgs decays at NLO in SMEFT?

Precise predictions for Higgs decays are crucial for new physics searches. Possible deviations from the Standard Model (SM) can be investigated in a model-independent way by using the Standard Model Effective Field Theory (SMEFT). We present the complete set of predictions for the 2- and 3- body Higgs decays at next-to-leading order (NLO), considering QCD and electroweak corrections and including all contributions from the dimension-6 SMEFT operators without flavor assumptions. We show how including the NLO SMEFT results for Higgs decays greatly increases the new physics sensitivity of the Higgstrahlung production process at FCC-ee.

Speaker: Clara Del Pio (Brookhaven National Lab)

31 Measurement of the Higgs properties at FCC-ee

The FCC-ee offers powerful opportunities to determine the Higgs boson parameters, exploiting about 2*10^6 e+e-→ZH events and almost 10^5 WW→H events at centre-of-mass energies around 240 and 365 GeV. The determination of the Higgs boson mass with a precision significantly better than the Higgs boson width (4.1 MeV in the Standard Model) is a prerequisite to either constrain or measure the electron Yukawa coupling via direct e+e-→H production at √s=125 GeV, as well as the being a limiting parametric uncertainty on the calculation of Higgs branching ratios. Approaching the statistical limit of 0.1% and O(1) MeV on the ZH cross section and the Higgs boson mass respectively, and of O(1%) on the Higgs total width, sets highly demanding requirements on accelerator operation (ZH threshold scan, centre-of-mass energy measurement), detector design (lepton momentum resolution, hadronic final state reconstruction performance), theoretical calculations, and analysis techniques (efficiency and purity optimization with modern tools, constrained kinematic fits, control of systematic uncertainties). The latest results included in the Feasibility Study recently finalized for the European Strategy Symposium will be presented.

Speaker: Nicola De Filippis (Politecnico/INFN Bari (IT))

32 The Higgs as a Portal to New Physics at a Muon Collider

The Higgs boson provides a unique window into new physics, and a high-energy muon collider offers an unparalleled environment to explore this potential. In this talk, I will discuss how a dedicated forward muon detector can be leveraged to probe BSM physics in the Higgs sector. Detecting forward muons allows us to efficiently search for invisible Higgs decays and heavy states that couple to the SM through the Higgs portal, providing e.g. the best discovery channel of derivatively coupled Higgs portal dark matter. In addition, angular correlations of the forward muons are sensitive to the quantum interference between SM and BSM vector boson helicity amplitudes, providing an excellent indirect probe of BSM physics coupled to the Higgs. As a case study, I will highlight how this approach can be applied to probe the CP structure of the Higgs–Z coupling.

Speaker: Maximilian Ruhdorfer (Stanford)

33 Higgs pair production at e+e- colliders

The Higgs mechanism is a cornerstone of the Standard Model, and its self-coupling is a key parameter for experimental verification. Double-Higgs production provides tree-level sensitivity to the trilinear self-coupling and becomes measurable at sufficiently high center-of-mass energies. At 550 GeV in electron–positron collisions, the dominant channel is di-Higgs strahlung, with a smaller contribution from WW fusion. The latest ILD projections are derived from a 2016 full-simulation analysis, updated to include anticipated improvements in flavor tagging and kinematic reconstruction for event selection. This work presents an ongoing re-analysis using the SGV fast simulation of the ILD detector concept, including the full Standard Model background, and compares the projected sensitivity with the most recent results from the HL-LHC program.

Speakers: Caterina Vernieri (SLAC National Accelerator Laboratory (US)), Julie Munch Torndal (Deutsches Elektronen-Synchrotron (DE))

Wednesday 29 October

Beyond the Standard Model Higgs

Talks are 20' (presentation) + 5' (discussion)

Parallel room, 20 Washington Place

Conveners: Ennio Salvioni (UAB and IFAE, Barcelona), Jingyu Luo (Brown University), Nathan Grieser (University of Cincinnati), Tatjana Lenz (University of Bonn)

34 Anomalous coupling and EFT measurement at CMS

Effective Field Theories and anomalous couplings including CP violation provide interesting ways to parameterize indirect BSM physics, when its characteristic scale is larger than the one directly accessible at the LHC, for a large class of models. Constraints on such effects derived by measurements of several production and decay modes of the Higgs boson and their combination on the data set collected by the CMS experiment will be presented.

Speaker: Nick Smith (Fermi National Accelerator Lab.)

35 Jet Bundle Geometry in Scalar EFT Amplitudes

Geometric methods have emerged in recent years, which allow for the expression of theories in a manifestly covariant form under field redefinitions through relating physical quantities to geometric structures.

Using jet bundles it is possible to express higher derivative terms in a geometric fashion, relating their couplings to the geometry of the bundle itself.

In this talk a brief introduction to jet bundles will be given as well as showcasing how the geometric objects may be treated as couplings which are invariant under field redefintions for terms with up to 4 derivatives.

Speaker: Mohammad Alminawi (University of Zurich)

Single Higgs measurements and calculations: Session 3

Talks are 17' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Clara Lavinia Del Pio (Brookhaven National Lab), Emanuele Di Marco (INFN, Roma 1 (IT)), Hannah Arnold (Stony Brook University)

36 Parton-shower and fixed-order QCD effects in weak-boson fusion and H → bb̄ decay

In this talk I will discuss differential theoretical predictions for Higgs-boson production in weak-boson fusion and its subsequent decay $H\to b\bar{b}$.

The distinct kinematics of weak-boson fusion allow us to suppress QCD backgrounds by imposing appropriate event selection criteria. However, it was recently observed that in fixed-order calculations these strict event selection criteria lead to large corrections - ~ -40% at NNLO in comparison to LO - with an apparent lack of perturbative convergence. One prominent source of such large effects is the tendency of the QCD radiation in the $H\to b\bar{b}$ decay to reduce the transverse momentum of b-jets to the point where they no longer pass the b-jet selection criteria.

I will show that these large kinematic effects are caused primarily by soft and collinear QCD radiation in the $H\to b\bar{b}$ decay subprocess and that they can be accounted for by using a parton shower. I will present NNLO-accurate predictions for the combined process $pp\to H(\to b\bar{b})jj$, where the $H\to b\bar{b}$ decay subprocess is matched to the Pythia parton shower using the MiNLO method. In comparison with purely fixed-order calculations the consistency of theoretical predictions is dramatically improved. The remaining theoretical uncertainty is of order 5-7%, primarily due to modelling of the differential $H\to b\bar{b}$ distributions.

Speaker: Ivan Novikov (Karlsruhe Institute of Technology (KIT))

slides.pdf

37 Measurements of Higgs boson production with top quarks with the ATLAS detector

The study of Higgs boson production in association with one or two top quarks offers a unique opportunity to probe the interactions between the two heaviest particles in the Standard Model. This talk presents measurements of key Higgs boson properties—specifically the production cross section and CP nature—in events produced via tH and t\bar{t}H processes. The results are based on the full Run 2 dataset of proton-proton collisions at $\sqrt{s}$ = 13 TeV, recorded by the ATLAS detector at the LHC.

Speaker: Alex May (The University of Manchester (GB))

38 Uncertainties for Higgs boson cross sections from PDFs and $\alpha_s$

The largest source of uncertainty for the gluon-gluon fusion HIggs boson cross section comes for the combination of PDF and $\alpha_s $ uncertainties. These uncertainties
also play a role in other Higgs boson subprocesses. This talk will focus on the current status of PDF uncertainties relevant for Higgs production and prospects for future improvements.
In addition, a preview of the 2025 PDG $\alpha_s $ average will be presented.

Speaker: Joey Huston (Michigan State University (US))

10:30 Break

Higgs Potential, Di-Higgs, and Multi-Higgs

Talks are 20' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Andreas Papaefstathiou (Kennesaw State University (US)), Liza Brost (Brookhaven National Laboratory (US)), Marina Kolosova (University of Florida (US)), William Balunas (University of Oxford (GB))

39 Triple Higgs Boson Production at the LHC and Beyond

Multi-Higgs boson production processes can provide essential insights into the scalar sector of the Standard Model (SM). Exploring the production of three Higgs bosons is primarily motivated by the unique opportunity it offers to measure the Higgs quartic self-coupling. Although observing triple Higgs production within the SM presents significant experimental challenges at the LHC, due to its exceptionally small cross section, the process becomes potentially observable in scenarios involving extended scalar sectors or anomalous couplings. In this talk, we will review the key theoretical and phenomenological aspects of triple Higgs boson production at hadron colliders, focusing on the information that can be extracted at current and future experiments.

Speaker: Andreas Papaefstathiou (Kennesaw State University (US))

40 HHH searches with CMS at the LHC

Speaker: Marko Stamenkovic (Brown University (US))

41 HHH searches with ATLAS at the LHC

In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. Experimentally, the Higgs boson trilinear and quadratic couplings and thereby the shape of the Higgs potential, can be probed through the production of double or triple Higgs pairs. This talk focuses on the on a search for non-resonant hhh production.

Speaker: Matthew🦜 Klein (Southern Methodist University (US))

Single Higgs measurements and calculations: Session 4

Talks are 17' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Clara Lavinia Del Pio (Brookhaven National Lab), Emanuele Di Marco (INFN, Roma 1 (IT)), Hannah Arnold (Stony Brook University)

42 Measurements of Higgs boson coupling properties to leptons with the ATLAS detector

Detailed measurements of Higgs boson decays into leptons provide a direct probe of the Yukawa interactions and the mechanism of fermion mass generation in the Standard Model. This talk presents the latest results from the ATLAS experiment on Higgs boson decays into pairs of tau leptons, using the full Run 2 dataset of proton-proton collisions at $\sqrt{s}​$=13 TeV, with the inclusion of available Run 3 results where relevant. These measurements test the Higgs couplings to leptons with increasing precision, offering important insights into the structure of the Higgs sector and potential deviations from Standard Model expectations.

Speaker: Tamas Marton Baer (University of Michigan (US))

43 STXS and differential cross section measurements at CMS, and their combination, with EFT interpretation

We will discuss the latest STXS and differential measurements of Higgs boson cross sections with the CMS detector in bosonic and fermionic decay channels and their combination. The data collected during Run 3 of the LHC by the CMS experiment are used. EFT interpretation will be added.

Speaker: Spencer Ellis (Brown University (US))

44 Combined Higgs boson measurements and their interpretations with the ATLAS experiment

Precision measurements of Higgs boson couplings and kinematic properties can be performed using the data collected by the ATLAS experiment, leveraging a variety of final states and production modes to probe different regions of phase space with increasing accuracy. By combining these measurements, the strengths of individual channels are maximally exploited, providing the most stringent global constraints on Higgs boson properties. This talk presents the latest combination of Higgs boson measurements by the ATLAS experiment, with results reported in terms of production modes, branching fractions, Simplified Template Cross Sections, and coupling modifiers. The results are based on proton-proton collision data collected at $\sqrt{s}$=13 TeV during Run 2 of the LHC.

Speaker: Yangfan Zhang (University of Science and Technology of China (CN))

Plenary

Main Auditorium, 20 Washington Place

45 One loop probes in the SMEFT

Speaker: Sally Dawson (BNL)

46 Solutions to the hierarchy problem through model building

Speaker: Thomas Steingasser

47 HEFT and non-decoupling BSM in Higgs sector

Speaker: Ilaria Brivio (University & INFN Bologna)

48 Precision measurements at the LHC - cross-section in different production modes, STXS

Speaker: Ximo Poveda Torres (IFIC, CSIC‐UV (ES))

15:30 Coffe break

Plenary

Main Auditorium, 20 Washington Place

49 Experimental methods (physics objects) in ATLAS

Speaker: Francesco Armando Di Bello (Universita & INFN Pisa (IT))

50 Experimental methods (physics objects) in CMS

Speaker: Alessandro Calandri (Università & INFN, Firenze (IT))

51 Discussion

52 Rare decays, including 2nd generation fermions, at the LHC

Speaker: Roberto Covarelli (University/INFN Torino (IT))

53 Conference dinner

Thursday 30 October

Higgs Physics at Future Colliders

Talks are 17' (presentation) + 5' (discussion)
Parallel room, 20 Washington Place

54 Prospects for single-Higgs measurements at the HL-LHC with the CMS experiment

The title says it all

Speaker: Ulrich Goerlach (Centre National de la Recherche Scientifique (FR))

55 Prospects for single-Higgs measurements at the HL-LHC with the ATLAS experiment

The High-Luminosity LHC (HL-LHC) is expected to deliver an integrated dataset of approximately 3 ab⁻¹, enabling detailed studies of Higgs boson processes with unprecedented precision. Projections based on current analyses have been performed to estimate the expected measurement accuracy and identify potential limitations. This talk will present the ATLAS experiment’s prospects for Higgs measurements at the HL-LHC.

Speaker: Sam Waterhouse (Royal Holloway, University of London (GB))

56 Detector Challenges at e+e- Higgs Factories

Speaker: Christopher Madrid (Texas Tech University (US))

Single Higgs measurements and calculations: Session 5

Talks are 17' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Clara Lavinia Del Pio (Brookhaven National Lab), Emanuele Di Marco (INFN, Roma 1 (IT)), Hannah Arnold (Stony Brook University)

57 Rare & BSM decays of the Higgs boson at CMS

We present searches for rare decays and beyond standard model of the Higgs boson with the CMS detector.

Speaker: Rui Zou (Cornell University (US))

58 Measurements of Higgs boson coupling properties to bottom and charm with the ATLAS detector

Probing the Yukawa couplings between the Higgs boson and fermions is essential to understanding the origin of fermion masses. Higgs boson decays into pairs of quarks offer a direct window into these couplings and broader Higgs boson properties. This talk presents ATLAS measurements of Higgs decays into bottom quark pairs and searches for decays into charm quark pairs, based on the full Run 2 dataset of proton-proton collisions at $\sqrt{s}$ = 13 TeV, with the inclusion of available Run 3 results where relevant.

Speaker: Louis-Guillaume Gagnon (Lawrence Berkeley National Lab. (US))

59 CMS Measurements of Higgs couplings to bottom and charm quarks including ttH

With the full run-2 data and with the advent of ML flavour tagging techniques, a lot of progress has been made to constrain the couplings of the Higgs to c-quarks and b-quarks. In this talk, we present the latest results of direct Higgs to heavy flavour couplings by the CMS experiment in the ttH/cH production, as well as the results obtained in indirect ways.

Speaker: Christopher Cosby (Fermi National Accelerator Lab. (US))

60 Theory uncertainties of the irreducible background to VBF Higgs production

Higgs boson production through gluon fusion in association with two jets is an irreducible background to Higgs boson production through vector boson fusion. Despite a range of available simulation tools, precise predictions for the corresponding final state are hard to achieve. Using state-of-the art fixed-order calculations as the baseline for a comparison, we perform a detailed study of similarities and differences in existing event generators. We find that NLO calculations for the two-jet final state are essential to achieve reliablel predictions.

Speaker: Joey Huston (Michigan State University (US))

10:30 Break

Beyond the Standard Model Higgs

Talks are 20' (presentation) + 5' (discussion)

Parallel room, 20 Washington Place

Conveners: Ennio Salvioni (UAB and IFAE, Barcelona), Jingyu Luo (Brown University), Nathan Grieser (University of Cincinnati), Tatjana Lenz (University of Bonn)

61 Search results for high-mass new scalars (including charged Higgs)

Though the Standard Model (SM) of particle physics has been a very successful theory in explaining a wide range of measurements, there are still many questions left unanswered such as incorporation of gravity into SM, neutrino masses, matter-antimatter asymmetry, supersymmetry, or existence of dark matter candidates. One of the possible solutions to address these challenges is the extension of the SM with the presence of additional, heavy BSM particles; including scalar (H/S), pseudoscalar (A), or charged (H+-/H++--) BSM Higgs bosons. This is accounted for in multiple possible new physics models predicting the existence of these new, heavy particles. This talk summarises recent ATLAS searches for Beyond-the-Standard-Model heavy resonances, including charged BSM Higgs bosons.

Speaker: Doyeong Kim (Argonne National Laboratory)

62 Models and constraints of pseudo Goldstone dark matter

Understanding the particle nature of dark matter remains one of the key challenges in contemporary physics. Although the thermal relic picture provides a natural explanation for the observed dark matter density, the continuing absence of positive signals in direct detection experiments calls into question the simplest WIMP hypotheses. A compelling alternative scenario emerges when dark matter originates as a pseudo-Goldstone particle associated with the breaking of a global symmetry. In this framework, the symmetry structure that generates the dark matter mass also governs its couplings, leading to interactions that diminish rapidly at low momentum transfer. We investigate a dark sector possessing an O(N) symmetry that is spontaneously broken to O(N-1), giving rise to a family of pseudo-Goldstone states. Introducing a small explicit breaking term lifts their degeneracy, leaving a single stable particle protected by a residual discrete symmetry. The remaining, nearly degenerate states can engage in coannihilation processes that significantly affect the freeze-out dynamics and determine the final relic abundance. This symmetry-based approach offers a natural mechanism for evading direct detection bounds while preserving the successful thermal history of dark matter, and it motivates new avenues for exploration through indirect searches and collider experiments.

Speaker: Sarah Farzand (University of Helsinki)

63 Additional resonance searches in Higgs sector

We present the searches for additional resonances in Higgs sector with the CMS detector. The presented results include searches in the low and high mass regions.

Speaker: Xiaohe Shen (Brown University (US))

Higgs Potential, Di-Higgs, and Multi-Higgs

Talks are 20' (presentation) + 5' (discussion)

Main Auditorium, 20 Washington Place

Conveners: Andreas Papaefstathiou (Kennesaw State University (US)), Liza Brost (Brookhaven National Laboratory (US)), Marina Kolosova (University of Florida (US)), William Balunas (University of Oxford (GB))

64 Search for VBS VVH with CMS Run 2 data

This talk presents a search for the production of a Higgs Boson in association with two vector bosons (VVH) via vector boson scattering (VBS). The VBS production of VVH is sensitive to both the Higgs boson trilinear self-coupling (HHH) and the quartic coupling between vector bosons and the Higgs boson (VVHH), potentially providing complementary constraints to those obtained from the di-Higgs program. Our search is based on LHC Run2 data, corresponding to 138 fb-1 recorded by the CMS detector at √s = 13 TeV. By targeting boosted signatures— enhanced in the presence of anomalous couplings— the analysis constrains the Higgs-gauge quartic coupling (HHVV) and sets the most stringent bounds to date on the WWHH and ZZHH couplings. Advanced tagging methods and machine learning techniques are used to identify boosted objects and estimate backgrounds. Prospective improvements to this analysis that could be applied starting with Run 3 and then HL-LHC data can also be discussed.

Speaker: Reyer Edmond Band (University of Notre Dame (US))

65 Overview of HH and Scalar+H resonance searches in ATLAS

The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional neutral Higgs-like bosons or additional heavy scalars. The current status of searches for these new scalars based on the full LHC Run 2 and some partial Run-3 results dataset of the ATLAS experiment at 13 TeV are presented.

Speaker: Jackson Barr (UCL)

66 Overview of HH and Scalar+H resonance searches in CMS

Searches for resonant Higgs bosons decaying into two scalar bosons have been attracting increasing attention at the Large Hadron Collider (LHC). The CMS Collaboration has studied various X→YH final states, and many beyond-the-Standard-Model (BSM) theories predict new scalar particles produced in association with the Standard Model Higgs boson. To further explore this sector, we present analyses targeting final states containing a pair of photons, with the other particle decaying via higher branching fraction modes (e.g., bbˉ or ττ). These analyses employ a parametric neural network (PNN), designed to efficiently probe a wide range of mass hypotheses and deliver competitive exclusion limits. The PNN naturally enables interpolation between simulated mass points, ensuring coverage of the full mass range. The presented results explore previously uncharted regions of parameter space, contributing an important piece to the broader puzzle of BSM models involving scalar bosons in the final state.

Speaker: Yanxi Gu (Univ. of California San Diego (US))

Plenary

Main Auditorium, 20 Washington Place

67 ATLAS and CMS results in EFT in and beyond Higgs Physics

Speaker: Rafael Coelho Lopes De Sa (University of Massachusetts (US))

68 Precision measurements at the LHC - properties: mass and width, couplings, CP, off-shell

Speaker: Linda Finco (INFN Torino (IT))

69 CPV in the Higgs sector

Speaker: Dorival Gonçalves (Oklahoma State University)

15:30 Coffe break

Plenary

Main Auditorium, 20 Washington Place

70 Experimental methods (analysis techniques) in CMS

Speaker: Alejandro Gomez Espinosa (Carnegie-Mellon University (US))

71 Experimental methods (analysis techniques) in ATLAS

Speaker: Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))

72 Discussion

73 Non-resonant HH searches and Higgs boson self-coupling at the LHC

Speaker: Liza Brost (Brookhaven National Laboratory (US))

74 Low-mass new scalars and Higgs decays to BSM particles at the LHC

Speaker: David Sperka (Boston University (US))

75 High-mass new scalars at the LHC, without H in the final state

Speaker: Ilia Kalaitzidou (Universite Libre de Bruxelles (BE))

76 Experimental Summary For Future Detectors (e+e-)

Speaker: Chris Palmer (University of Maryland (US))

Friday 31 October

Plenary

Main Auditorium, 20 Washington Place

77 High-mass new scalars at the LHC, with H in the final state

The search for new particles, conducted at the LHC by the ATLAS and CMS collaborations, covers several production and decay modes, leading to a large variety of final states that could be observed in both detectors. This review focuses on the production of new heavy scalars that have a Higgs boson in the final state. In particular, the three cases: resonant production of a heavy scalar X decaying into a Higgs boson and a lighter scalar S, heavy neutral Higgs boson decaying into another neutral Higgs boson and a Z boson, and a heavy charged Higgs boson production with subsequent decay into another neutral Higgs boson and a W boson. The reviewed searches are based on the complete LHC Run-2 dataset and partial Run-3 dataset.

Speaker: Andre Sopczak (Czech Technical University in Prague (CZ))

78 Higgs and ALPs

Speaker: Alexandre Salas-Bernárdez (Universidad Complutense de Madrid)

79 Higgs and BSM: Future Colliders crossover

Speaker: Benjamin Stefanek (IFIC Valencia)

11:00 Coffe break

Plenary

Main Auditorium, 20 Washington Place

80 Higgs Couplings and self-coupling at future colliders

Speaker: Luca Mantani (IFIC, Valencia)

81 CPV in the Higgs sector

Speaker: dorival Gonçalves (Oklahoma State University)

82 Experimental Summary: Physics (e+e-)

Speaker: Michele Selvaggi (CERN)

83 Closing experimental talk

Speaker: Valerio Dao (Stony Brook University)

84 Higgs 2026