Fabio Maltoni

Academic staff


Centre for Cosmology, Particle Physics and Phenomenology - CP3
Université catholique de Louvain
2, Chemin du Cyclotron - Box L7.01.05
B-1348 Louvain-la-Neuve

+32 10 47 3166


Personal homepage

UCL member card
Teaching at UCL
Quantum Mechanics
First course on Quantum Mechanics.
45h+30h, 5 ECTS

Relativistic Quantum Mechanics
Introduction to the Dirac Equation.
15h+15h, 4 ECTS

Electroweak interactions
Introduction to the Standard Model of the electroweak interactions.
22.5h, 4 ECTS (shared with J.M.Gerard)

Strong interactions and symmetries
Introduction to perturbative QCD and symmetries
30h, 5 ECTS (shared with J.M.Gerard)

Seminars of theoretical and mathematical physics
Invited lectures on special topics.
15h, 2 ECTS.
People responsibilities
Rafael Aoude (UCL-FSR - FSR21) (member since October 2020)
My interests are in the effective description of the Standard Model of particle physics and Gravity. I work in SMEFT phenomenology and in the use of modern methods for scattering amplitudes to understand Effective Field Theories for BSM particle physics and General Relativity.
Ramon Winterhalder (IISN - MAX LHC) (member since September 2021)
I work on the intersection of particle physics and machine learning. My research aims to fully establish data-driven techniques in high-energy physics and to enhance standard simulation methods with (generative) neural networks.

PhD students
Tommaso Armadillo (FNRS - Aspirant) (member since January 2022)
I am working on the development of methods and tools to advance our ability to perform precision studies at colliders and apply them to key novel computations. In particular, we aim at introducing new techniques for two-loop integrals that are currently the bottleneck of next-to-next-to-leading order (NNLO) electroweak and use them to obtain predictions for Drell-Yan process at the LHC and for ZH production at future electron-positron colliders.
Daniele Massaro (member since May 2019)
My research is focused on astroparticle physics, in particular on dark sector, neutrinos and dark matter. I am working on dark sector phenomelogy, studying new beyond Standard Model models scenarios trying to explain problems, such as dark matter or neutrino masses, according the several experimental constraints. I am also active in the development of the tool "MadDM", which is an automated numerical tool for the computation of dark matter observables for generic new physics models.
Simone Tentori (EOS) (member since January 2023)
I study particle physics phenomenology in colliders, both SM and BSM, with particular attention to top-philic interaction.
Zeqiang Wang
(1) Improve the accuracy of the SMEFT predictions (2) Advance the SMEFiT technology (3) Perform global analyses of HEP data with optimal observables.

Master students



Former members
Research statement
The high energy and luminosity of the present and future colliders, from the Tevatron (FNAL) to the Large Hadron Collider (CERN) to a Tev Linear Collider, will offer the widest range of physics opportunities to the exploration of the high-energy frontier. Among the highest priorities is understanding not only the nature of the electroweak symmetry breaking (EWSB) but also the mechanism through which the electroweak scale stabilizes. Simple and very robust arguments indicate that this scale should be less than one TeV, very much in the reach of the above mentioned colliders. At this energy, spectacular events take place and mulijet final states in association with leptons or missing energy constitutes the most interesting data samples. The quest for the Higgs boson(s) and/or for supersymmetric particles will rely on our ability of predicting both the signal and the standard model processes which are the backgrounds of these searches.

The difficulty of detecting such signatures asks for a dedicated and joint effort of all the high-energy physics community. Not only the best theoretical predictions for the expected signals will be necessary, but also a very good understanding of the large QCD backgrounds and the detectors responses will allow us to unreveal the mechanism of EWSB. In this respect, I consider of primary importance for theorists to work in close contact with experimentalists.

In the next crucial years which will see the first new data from the LHC, I plan to focus my efforts in two main directions:

  1. provide new and/or more precise evaluations of the most important signatures that probe the the EWSB mechanism, such as top and Higgs boson(s) production both in the standard model and its extensions.
  2. provide the experimentalists at the colliders with the means to simulate events occurring at the energy frontier.
Research directions:
Data analysis in HEP, astroparticle and GW experiments
Phenomenology of elementary particles

Experiments and collaborations:

Active projects
Advanced Multi-Variate Analysis for New Physics Searches at the LHC
Agni Bethani, Christophe Delaere, Andrea Giammanco, Vincent Lemaitre, Fabio Maltoni

With the 2012 discovery of the Higgs boson at the Large Hadron Collider, LHC, the Standard Model of particle physics has been completed, emerging as a most successful description of matter at the smallest distance scales. But as is always the case, the observation of this particle has also heralded the dawn of a new era in the field: particle physics is now turning to the mysteries posed by the presence of dark matter in the universe, as well as the very existence of the Higgs. The upcoming run of the LHC at 13 TeV will probe possible answers to both issues, providing detailed measurements of the properties of the Higgs and extending significantly the sensitivity to new phenomena.

Since the LHC is the only accelerator currently exploring the energy frontier, it is imperative that the analyses of the collected data use the most powerful possible techniques. In recent years several analyses have utilized multi-variate analysis techniques, obtaining higher sensitivity; yet there is ample room for further improvement. With our program we will import and specialize the most powerful advanced statistical learning techniques to data analyses at the LHC, with the objective of maximizing the chance of new physics discoveries.

We have been part of AMVA4NewPhysics, a network of European institutions whose goal is to foster the development and exploitation of Advanced Multi-Variate Analysis for New Physics searches. The network offered between 2015 and 2019 extensive training in both physics and advanced analysis techniques to graduate students, focusing on providing them with the know-how and the experience to boost their career prospects in and outside academia. The network develops ties with non-academic partners for the creation of interdisciplinary software tools, allowing a successful knowledge transfer in both directions. The network studies innovative techniques and identifies their suitability to problems encountered in searches for new physics at the LHC and detailed studies of the Higgs boson sector.

External collaborators: University of Oxford, INFN, University of Padova, Université Blaise Pascal, LIP, IASA, CERN, UCI, EPFL, B12 Consulting, SDG Consulting, Yandex, MathWorks.
Complementarity of dark matter searches in simplified models
Chiara Arina, Fabio Maltoni

Study of the complementarity between dark matter relic abundance, direct detection, indirect detection and collider searches applied to the dark matter simplified models. These models consider a dark matter candidate communicating to the quark (especially top) sector of the standard model via a bosonic or vectorial mediator.

External collaborators: Eric Conte (GPRHE), Benjamin Fuks (LPTHE), Jun Guo (Chinese Academy of Science), Jan Heisig (RWTH), Kentarou Mawatari (LPSC Grenoble), Michael Kraemer (RWTH), Mathieu Pellen (University of Wuerzburg).
Céline Degrande, Fabio Maltoni

Implementation of the SMEFT at NLO in QCD in the Feynrules MadGraph5_aMC@NLO chain and phenomenological studies

External collaborators: Cen Zhang, Celine Degrande.
Electroweak corrections
Fabio Maltoni

Automation of the calculation of NLO Electroweak corrections and phenomenological studies of their impact on Standard-Model and Beyond-the-Standard-Model processes at colliders.
Céline Degrande, Fabio Maltoni

An automated framework for BSM phenomenology that allows one to compute Feynman rules from a Lagrangian.

External collaborators: Céline Degrande (CERN) Benjamin Fuks (Jussieu).
Higgs phenomenology at the LHC
Fabio Maltoni

We study the Vector Boson Fusion production channel for the Higgs boson and other particles at the LHC, mainly focusing on the role of QCD corrections.
Loop-induced processes in the SM and Beyond
Fabio Maltoni, Olivier Mattelaer

Automation within MadGraph5_aMC@NLO and phenomenological studies of loop-induced processes for the LHC
Fabio Maltoni, Olivier Mattelaer

Monte Carlo development.

External collaborators: Benjamin Fuks, Kentarou Mawatari, Kaoru Hagiwara, Tim Stelzer, Stefano Frixione, Marco Zaro, Rikkert Frederix, Valentin Hirschi, Paolo Torrielli, Johan Alwall, Hua-Sheng Shao, Mihailo Backovic,...
Search for nonresonant Higgs boson pair production in the llbb+MET final state
Agni Bethani, Christophe Delaere, Vincent Lemaitre, Fabio Maltoni

The discovery of a Higgs boson (H) by the ATLAS and CMS experiments fixes the value of the self-coupling λ in the scalar potential whose form is determined by the symmetries of the Standard Model and the requirement of renormalisability. Higgs boson pair production is sensitive to the self-coupling and will play a major role in investigating the scalar potential structure.

This project consists in a search for nonresonant Higgs boson pair production via gluon fusion in the final state with two leptons, two b jets and missing transvere energy – gg → H(bb) H(WW) asking for the leptonic decay of the W's. The analysis is conducted in close collaboration with phenomenologists to ensure the approach is theoretically sound and future-proof.
Study of processes with heavy quarks in the initial state
Fabio Maltoni

The difference between predictions obtained with a massive scheme, where a heavy quark is treated as a finale massive state and the massless scheme, where the heavy quark is viewed as an initial parton may be extremely sizable. The aim of the project is to gain a better understanding of the size of the collinear logarithms arising when a heavy quark is treated as a final massive state and to investigate its kinematical origin.

External collaborators: Maria Ubiali, Giovanni Ridolfi.

Non-active projects
Publications in IRMP
All my publications on Inspire

Number of publications as IRMP member: 135
Last 5 publications


IRMP-CP3-23-37: Probing new physics through entanglement in diboson production
Aoude, Rafael and Madge, Eric and Maltoni, Fabio and Mantani, Luca

[Abstract] [PDF]
Refereed paper. July 18.
IRMP-CP3-23-34: Quantum SMEFT tomography: Top quark pair production at the LHC
Aoude, Rafael and Madge, Eric and Maltoni, Fabio and Mantani, Luca

[Abstract] [PDF] [Local file] [Journal] [Dial]
Refereed paper. July 2.
IRMP-CP3-23-33: Resummation effects in the bottom-quark fragmentation function
Maltoni, Fabio and Ridolfi, Giovanni and Ubiali, Maria and Zaro, Marco

[Abstract] [PDF] [Local file] [Journal] [Dial]
Refereed paper. July 2.
IRMP-CP3-23-32: Quantum information and CP measurement in H->tau+tau- at future lepton colliders
Altakach, Mohammad Mahdi and Lamba, Priyanka and Maltoni, Fabio and Mawatari, Kentarou and Sakurai, Kazuki

[Abstract] [PDF] [Local file] [Journal] [Dial]
Refereed paper. July 2.


IRMP-CP3-22-56: MadNIS -- Neural Multi-Channel Importance Sampling
Heimel, Theo and Winterhalder, Ramon and Butter, Anja and Isaacson, Joshua and Krause, Claudius and Maltoni, Fabio and Mattelaer, Olivier and Plehn, Tilman

[Abstract] [PDF]
Refereed paper. December 10.

More publications