Jérôme de Favereau
Research scientist. Funding: FNRS.
Member since October 2002
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 3113
UCL member card
I am involved in the following research directions:

a C++ software package to compute Matrix Element weights: MoMEMta

MoMEMta is a C++ software package to compute Matrix Element weights. Designed in a modular way, it covers the needs of experimental analysis workflows at the LHC. MoMEMta provides working examples for the most common final states (Formula: 0, WW, ...). If you are an expert user, be prepared to feel the freedom of configuring your MEM computation at all levels.
MoMEMta is based on:

- C++, ROOT, Lua scripting language
- Cuba (Monte-Carlo integration library)
- External PDFs (LHAPDF by default)
- External Matrix Elements (currently provided by our MadGraph C++ exporter plugin)

Development of a framework for fast simulation of a generic collider experiment: Delphes

Observability of new phenomenological models in High Energy experiments is delicate to evaluate, due to the complexity of the related detectors, DAQ chain and software. Delphes is a new framework for fast simulation of a general purpose experiment. The simulation includes a tracking system, a magnetic field, calorimetry and a muon system, and possible very forward detectors arranged along the beamline. The framework is interfaced to standard file format from event generators and outputs observable analysis data objects. The simulation takes into account the detector resolutions, usual reconstruction algorithms for complex objects (FastJet) and a simplified trigger emulation. Detection of very forward scattered particles relies on the transport in beamlines with the Hector software.

The CMS silicon strip tracker upgrade

Development of the "phase II" upgrade for the CMS silicon strip stracker.

More precisely, we are involved in the development of the uTCA-based DAQ system and in the test/validation of the first prototype modules. We take active part to the various test-beam campaigns (CERN, DESY, ...)

This activity will potentially make use of the cyclotron of UCL, the probe stations and the SYCOC setup (SYstem de mesure de COllection de Charge) to test the response to laser light, radioactive sources and beams.

The final goal is to take a leading role in the construction of part of the CMS Phase-II tracker.

External collaborators: CRC and CMS collaboration.

World LHC Computing Grid: the Belgian Tier2 project

The World LHC Computing GRID (WLCG) is the worldwide distributed computing infrastructure controlled by software middleware that allows a seamless usage of shared storage and computing resources.

About 10 PBytes of data are produced every year by the experiments running at the LHC collider. This data must be processed (iterative and refined calibration and analysis) by a large scientific community that is widely distributed geographically.

Instead of concentrating all necessary computing resources in a single location, the LHC experiments have decided to set-up a network of computing centres distributed all over the world.

The overall WLCG computing resources needed by the CMS experiment alone in 2016 amount to about 1500 kHepSpec06 of computing power, 90 PB of disk storage and 150 PB of tape storage. Working in the context of the WLCG translates into seamless access to shared computing and storage resources. End users do not need to know where their applications run. The choice is made by the underlying WLCG software on the basis of availability of resources, demands of the user application (CPU, input and output data,..) and privileges owned by the user.

Back in 2005 UCL proposed the WLCG Belgian Tier2 project that would involve the 6 Belgian Universities involved in CMS. The Tier2 project consists of contributing to the WLCG by building two computing centres, one at UCL and one at the IIHE (ULB/VUB).

The UCL site of the WLCG Belgian Tier2 is deployed in a dedicated room close to the cyclotron control room of the IRMP Institute and is currently a fully functional component of the WLCG.

The UCL Belgian Tier2 project also aims to integrate, bring on the GRID, and share resources with other scientific computing projects. The projects currently integrated in the UCL computing cluster are the following: MadGraph/MadEvent, NA62 and Cosmology.

External collaborators: CISM (UCL), Pascal Vanlaer (Belgium, ULB), Lyon computing centre, CERN computing centre.

Past projects
Hide past projects.

I am involved in the following research directions:

Advanced Techniques for Fast Simulation and Data Analysis in High Energy Physics (ASAP)

The discovery of the 125GeV Higgs boson by the LHC experiments has finally opened a new era in the exploration of the TeV scale. The physics programs of CMS and ATLAS aim far beyond the simple discovery, and vigorously pursue the full characterization of the newly discovered state and the full exploration of the TeV scale in search of new phenomena. A key lesson drawn from first two years of LHC running is that most probably first discoveries and then identification of new states/interactions will not be easy. On the one hand, model-independent searches in simple topologies such as single/multi lepton at high transverse momenta have not shown any hint of new physics so far. On the other, topologies with jets and/or missing transverse energies, much more challenging experimentally, do strongly depend on the underlying theoretical models so that efficiently identifying signal enhanced regions of the phase space is quite involved. In this context, multi-variate techniques have become more and more central in the analysis of data from hadron collider experiments, to maximally exploit the information available on the signal and on the backgrounds. Amongst the most advanced techniques and certainly the most powerful one from the theoretical point of view, the so called matrix element method stands out. The main goal of this proposal is to advance the use and the scope of the matrix-element method so to significantly extend the range of physics applications at the LHC to the search of new physics. First we aim at providing the experimental HEP community with complete and automatic simulation tools, such as MadWeight/MoMEMta and Delphes, that overcome the technical limitations of the method. Second we propose to test and apply the new tools to current analyses in signatures that involve final state leptons and b-jets. Finally, we explore new and original applications of the method to both model-dependent or model-independent searches of new physics at the LHC.

External collaborators: CMS collaboration.

Anomalous interactions between the photon and top quark

We study the observation of single top quarks in photoproduction at the LHC as a way of detecting the presence of flavour changing neutral currents, predicted by some theories beyond the standard model.

Hector, the simulator

Hector is a fast, multi-purpose simulator for the path of particles into beamlines.

It is build to be adaptative to any beamline and is already used by people from CMS (as a part of the official software) and ATLAS at the LHC and STAR at RHIC.

It is written in C++ and uses the ROOT framework to provide nice tools for analysis.

Results were cross-checked versus MAD-X, the official software used by the LHC machine group. It already allowed to obtain many estimations in terms of acceptance and resolutions of very forward detectors, as well as the effect of beamline misalignements and other related important topics related to forward detectors.

In collaboration with Xavier Rouby (Freiburg, D).

Measurement of the b(b)Z process at LHC

At LHC, the Z boson can be produced in association with one or two b-quarks, which is here refereed as b(b)Z production. This process has been seen for the first time at LHC, and measurement of it is an important test of QCD calculations.

For the first time, we observed the Z+b final state and measured of the Z+b/Z+j cross-section ratio in 35.9/pb of pp collisions at 7 TeV, using particle flow jets and simple secondary vertex b-tagging algorithm in the definition of the signal.Emphasis is put on kinematic properties of the jets. With more luminosity, we are working on the measurement of the cross-section for the b(b)Z process, with the identification of one or two b-jets.

External collaborators: A.Gilbert, A.-M.Magnan, A.Nikitenko (Imperial College London); N.Heracleous, A.Perieanu (RWTH Aachen); M.Musich, E.Migliore (University of Torino), and CMS Collaboration.

Search for Higgs boson(s) in CMS at the LHC in the llbb topology

Search for Higgs boson(s) within the Standard Model and beyond and also withing a minimal extension of the scalar sector (2HDM).

The final state under study is a Z decaying into a lepton pair associated with two b-jets. This topology is sensitive to a light SM Higgs via the associate ZH production, as well as a middle mass range SM Higgs boson via the inclusive Higgs production followed by its decay into ZZ with one Z decaying into a lepton pair and the other into bbar.

It is also very sensitive to the production of a non standard heavy Higgs boson decaying into Z plus A (pseudo scalar Higgs boson).

Similar selection (but outside of the Z window) is also sensitive to H->aa->llbb, with "a" a generic light scalar.

External collaborators: CMS collaboration.

Validation of a fully automatic matrix element technique for CMS data analyses

The matrix element reweighting method attempts to compute the full likelihood of an observed event given a theoretical model. The method therefore measures the degree of compatibility of the event with the given model using as much information as available. MadWeight is a tool that fully automatize the computation of the event likelihood for any model implemented in MadGraph, by performing phase-space integration and providing a framework for taking into account the experimental resolution on the observed final state objects.
This project aims at validating the matrix element reweighting technique implemented in MadWeight on a number of benchmark searches. In some cases, the final goal is the efficient identification of background events. The final states that are being considered are: Zbb, single top, ttbar resonances and dimuon resonances.

Publications in CP3
All my publications on Inspire


Evidence for the direct decay of the 125 GeV Higgs boson to fermions
Chatrchyan, Serguei and others
[Abstract] [PDF] [Journal] Subjects: High Energy Physics - Experiment (hep-ex)
Journal reference: Nature Physics 10 (2014) 557
DOI: 10.1038/nphys3005
Report number: CMS-HIG-13-033, CERN-PH-EP-2014-004

Refereed paper. 1st July.


Measurement of the production cross sections of a Z boson in association with b jets in pp collisions at sqrt(s) = 7 TeV
The CMS Collaboration
[Full text] First presented at DIS 2013
Public experimental note. 26th August.
Measurement of the cross section of the production of a Z boson in association with 1, 2, or more b jets at CMS in pp collisions at sqrt(s)=7 TeV.
Tristan du Pree, Roberto Castello, Ludivine Ceard, Anne-Marie Magnan, Andrew Gilbert, Christophe Delaere, Adrien Caudron, Jerome de Favereau
[Full text] CMS internal document supporting CMS-SMP-13-004
Private experimental note. 26th August.
DELPHES 3, A modular framework for fast simulation of a generic collider experiment
de Favereau, J. and others
[Abstract] [PDF] [Journal] Published in JHEP
Refereed paper. 25th July.


Measurement of the Z/gamma*+b-jet cross section in pp collisions at 7 TeV
Chatrchyan, SergueiProg. Part. Nucl. Phys. and others
[Abstract] [PDF] [Journal] [Full text] Published in the Journal of High Energy Physics
Refereed paper. 10th April.
Observation of the Z+b final state and measurement of the Z+b/Z+j cross-section ratio in pp collisions at 7 TeV
Tristan du Pree, Ludivine Ceard, Jerome de Favereau, Christophe Delaere
[Full text] Restricted access: CMS internal document supporting CMS PAS-EWK-10-015
Private experimental note. 9th February.


Observation of Z+b, Z -> ee, mumu with CMS at sqrt(s)=7TeV.
The CMS Collaboration
[Full text] Prepared for 2010 Winter Conferences (Moriond)
Public experimental note. 11th March.
Observation of the Z+b final state and measurement of the Z+b/Z+j cross-section ratio in pp collisions at 7 TeV
L. Ceard, J. de Favereau, C. Delaere and T. du Pree
[Full text] CMS analysis note, in relation to EWK-10-015
Private experimental note. 11th March.


CMS Tracking Performance Results from early LHC Operation
CMS collaboration
[Abstract] [PDF] [Journal] [Full text] Published in Eur.Phys.J.C70:1165-1192,2010.
Refereed paper. 21st December.


CMS Data Processing Workflows during an Extended Cosmic Ray Run
CMS Collaboration
[Abstract] [PDF] [Journal] [Full text] Published in JINST
Refereed paper. 21st December.


The CMS experiment at the CERN LHC
The CMS Collaboration
[Journal] [Full text] The CMS Collaboration, "The CMS experiment at the CERN LHC", 2008 JINST 3 S08004, 361pp doi: 10.1088/1748-0221/3/08/S08004.
Refereed paper. 10th December.
Single top quark photoproduction at the LHC
de Favereau de Jeneret, J. and Ovyn, S.
[Abstract] [PDF] [Journal] Contribution to the CERN workshop on high energy photon collisions at the LHC, April 2008
Contribution to proceedings. 1st July.
High energy single top photoproduction at the LHC
S. Ovyn and J. de Favereau de Jeneret
[Abstract] [PDF] Presented at the International Workshop on Top Quark Physics (TOP2008), La Biodola, Isola d'Elba, Italy, May 2008. To be published in "Il nuovo cimento"
Contribution to proceedings. 29th June.
High energy photon interactions at the LHC
J. de Favereau et al.
[Abstract] [PDF] [Full text] Submitted. See CP3-09-37.
28th January.


Hector, a fast simulator for the transport of particles in beamlines
J. de Favereau, X. Rouby, K. Piotrzkowski
[Abstract] [PDF] [Journal] [Full text] Published in JINST2:P09005,2007
Refereed paper. 14th May.

[UCLouvain] - [SST] [IRMP] - [SC] [PHYS]
Contact : Vincent Boucher & Jérôme de Favereau
Job opportunities PhD position in NA62 experiment