Contact
Name
Sébastien Brochet

Position
Former member
Postdoc in CP3 from March 2015
Projects
Research directions:
Phenomenology of elementary particles
Data analysis in HEP experiments

Experiments and collaborations:
CMS

Active projects
a C++ software package to compute Matrix Element weights: MoMEMta
Jérôme de Favereau, Christophe Delaere, Pavel Demin, Vincent Lemaitre, Alessia Saggio

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)
Search for non-resonant new physics in ttbar production
Vincent Lemaitre

The lack of observed resonances produced at the LHC motivates finding new ways of searching for BSM phenomena. This project aims at discovering possible non-resonant New Physics affecting the production of Top quark pairs, by means of a dedicated analysis of data recorded by the CMS experiment. The New Physics effects are modeled using an effective field theory (EFT), whose parameters are to be measured or constrained in a global fit.

The analysis is conducted in close collaboration with phenomenologists to ensure the approach is theoretically sound and future-proof.
Search for nonresonant Higgs boson pair production in the llbb+MET final state
Christophe Delaere, Martin Delcourt, 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.
Search for resonant Higgs pair production in the llbb+MET final state
Christophe Delaere, Martin Delcourt, Vincent Lemaitre

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.

Non-active projects
Publications in CP3
All my publications on Inspire

Number of publications as CP3 member: 5 Download BibTeX

2017

CP3-17-56: The Phase-2 Upgrade of the CMS Tracker
CMS collaboration

[Full text]
CERN-LHCC-2017-009 ; CMS-TDR-014
Refereed paper. December 13.
CP3-17-30: Search for resonant production of two Higgs bosons in the b-blν lν final state in 2016 data
O. Bondu, S. Brochet, C. Delaere, M. Delcourt, B. Francois, V. Lemaitre, M. Vidal Marono, S. Wertz

[Full text]
CMS AN-2016/444; Restricted access
Private experimental note. August 21.
CP3-17-29: Search for production of two Higgs bosons in the b-blν lν final state in 2016 data
O. Bondu, S. Brochet, C. Delaere, M. Delcourt, B. François, V. Lemaître, M. Vidal Marono, S. Wertz

[Full text]
Restricted access; CMS AN-2016/430
Private experimental note. August 21.
CP3-17-28: Search for resonant and nonresonant Higgs boson pair production in the bblnulnu final state in proton-proton collisions at sqrt(s) = 13 TeV
CMS collaboration

[Abstract] [PDF] [Journal] [Dial] [Full text]
Published in JHEP 1801 (2018) 054
Refereed paper. August 21.

2016

CP3-16-20: Search for H(WW)H(bb) decays using the 2015 data sample
CMS collaboration

[Full text]
prepared for Moriond 2016
Public experimental note. April 28.