Christophe Delaere
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 3207
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LPHY1342 - Etat solide
Ce cours constitue une introduction à la physique de l'état solide. En ce sens, sont abordés les différentes propriétés thermiques et électriques du solide. On mettra l'accent sur l'application des notions de base aux semi-conducteurs (applications micro-électroniques et techniques de détection des particules chargées) et à la supraconductivité.
MAFY1181 - Actualité de la physique
Cette activité a pour but de motiver l'étudiant en lui donnant une image ouverte et attrayante de la physique et des mathématiques d'aujourd'hui. Elle l'aidera aussi à préciser son choix d'études au-delà de la première année.
Mon séminaire porte sur le démarrage du LHC et les principaux objectifs de l'expérience CMS, parmis lesquels la recherche du boson de Higgs.
LPHY2131 - Physique des particules élémentaires I
Pour 1/3 du cours : Rappel : Constantes fondamentales et unités Matière ordinaire et unifications (quark-lepton) Anti-matière et symétries discrètes (C,P,T) Matière extraordinaire et masses (matrices de mélange CKM et MNS) Pour 2/3 du cours : partie expérimentale On discute ici plus en détail les expériences présentées dans le cours PHY1331. Une revue des découvertes de ces particules + des expérience liées à la violation de CP
LPHY2135 - Computing et Méthodes numériques en physique des particules
Sélection en ligne d'événements (systèmes de déclanchement et sélection hardware et software) - Méthodes de reconstruction d'événements : Tracking, vertexing, clustering et identification de particules. Techniques de calibration et alignement. - Techniques d'analyse des données - Générateurs MonteCarlo d'interactions entre particules - Simulation de la propagation de particules dans la matière. Des travaux personnels, largement informatisés, ayant pour but la simulation d'une expérience en physique des particules intégreront les cours théoriques.
People responsibilities
Olivier Bondu (FNRS), member since March 2015
I am a CMS experimentalist interested in connections between the Higgs boson and physics Beyond the Standard Model. In particular I am working on di-Higgs production at the LHC in the HbbHgg and HbbHWW channels. While the Standard Model cross-section of these process is very low, I am studying resonant production (WED, 2HDM, MSSM), and anomalous non-resonant production (EFT).

Miguel Vidal Marono (FNRS), member since July 2013
Experimentalist at the CMS experiment. Higgs searches and advanced techniques for data analysis in high energy physics (MoMEMta).

PhD students
Martin Delcourt (UCL), member since September 2014
Development of a new tracker for the CMS upgrade phase 2 and study of the feasibility of measurements at the HL-LHC.

Alexandre Mertens (IISN), member since September 2011
Interested in fast detector simulation and data analysis. In particular, the application of the Matrix Element Method to study the scalar sector.

Alessia Saggio (AMVA4NP), member since January 2016
Experimentalist, involved in the development of new tools for multi-variate analysis and member of the CMS collaboration.

Master students
Auriane Canesse, member since September 2016

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)

Advanced Multi-Variate Analysis for New Physics Searches at the LHC

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 are part of a network of European institutions whose goal is to foster the development and exploitation of Advanced Multi-Variate Analysis (AMVA) for New Physics searches. The network offers 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.

CMS Tracker commissioning and performance assessment

The CMS silicon strip tracker is the largest device of its type ever built. There are 24244 single-sided micro-strip sensors covering an active area of 198m2.
Physics performance of the detector are being constantly assessed and optimized as new data comes.
Members of UCL are playing a major role in the understanding of the silicon strip tracker and in the maintenance and development of the local reconstruction code.

External collaborators: CMS tracker collaboration.

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.

Search for nonresonant Higgs boson pair production in the llbb+MET final state

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.

Search for resonant Higgs pair production in the llbb+MET final state

The recent discovery of a scalar boson compatible with the Standard Model (SM) Higgs boson opened new windows to look for physics beyond the SM (BSM). An example of newly accessible phenomenology is the production of resonances decaying into two SM Higgs bosons (h) predicted by several theory families such as additional Higgs singlet/doublet or warped extra dimension.

This project consists in a search for spin-0 or spin-2 resonances produced via gluon fusion in the final state with two leptons, two b-jets and missing transverse energy – gg → X → h(bb) h(WW) asking for the leptonic decay of the W's. In particular, we are probing a mass range between 260 GeV and 900 GeV.

Study and optimization of b-tagging performances in CMS

We are involved in the activities of the btag POG (performance object group) of CMS, in release and data validation and purity measurement. We are also interested in btagging in special cases like for colinear b-jets. Furthermore, we are involved in the re-optimization and improvement of the Combined Secondary Vertex (CSV) tagger for the 2012 analyses.

External collaborators: Strasbourg CMS group, CMS collaboration.

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.

Show past projects.
Publications in CP3
Showing 5 publications over 39. Show all publications.
All my publications on Inspire


Search for H(WW)H(bb) decays using the 2015 data sample
CMS collaboration
[Full text] prepared for Moriond 2016
Public experimental note. 28th April.
Search for A/H to Z(ll)+H/A(bb) with 2015 data
CMS collaboration
[Full text] Prepared for Moriond 2016
Public experimental note. 28th April.
Search for Neutral Resonances Decaying into a Z Boson and a Pair of b Jets or Tau Leptons
CMS collaboration
[Abstract] [PDF] [Journal] [Full text] Published in Phys. Lett. B 759 (2016) 369
Refereed paper. 28th April.
Summary results of high mass BSM Higgs searches using CMS run-I data
CMS Collaboration
[Full text] CMS Physics Analysis Summary CMS-PAS-HIG-16-007,
Public experimental note. 22nd April.


Search for H/A decaying into Z and A/H, with Z-->ll and A/H-->bb or A/H-->tau tau
CMS Collaboration
[Full text] CMS-PAS-HIG-15-001
Public experimental note. 1st December.

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Job opportunities PhD position in NA62 experiment