Contact
Name
Jean-Marc Gérard

Position
Professor

Email
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
Belgium

Phone
+32 10 47 2712

Office
UCL member card
Teaching
Special Relativity
Introduction to kinematics and dynamics in Minkowski space-time.
PHY1223 (22.5h + 15h; shared with J.Govaerts)

General Relativity
Introduction to Einstein's theory of gravity.
PHY1323 (30h + 15h)

Quantum field theory 1
Introduction to Quantum Electrodynamics.
PHY2120 (22.5h)

Fundamental interactions
Introduction to electroweak, strong and gravitational interactions.
PHY2121 (22.5h)

Strong interactions and symmetries
Introduction to perturbative QCD and to hadron physics.
PHY2223 (30h; shared with F.Maltoni)

Electroweak interactions
Introduction to the Standard Model.
PHY2224 (22.5h; shared with F.Maltoni)
People responsibilities
Postdocs
Jan Hajer (IISN) (member since October 2017)
BSM Phenomenology. Higgs physics, naturalness of the SM, SUSY. Hidden particles at NA62.

Former members
Research statement
My interests cover the phenomenology of the four fundamental interactions.
Strong interactions
The use of an effective theory for Quantum Chromo Dynamics in the large-N limit to cast a new glance on:
-the U(1) problem and the resulting strong CP-violation;
-the non-perturbative effects on and hadronic decays.

Electroweak interactions
The use of Quantum Flavor Dynamics to get theoretical constraints on:
-the fermion mixings and the resulting weak CP-violation;
-the boson mass spectrum in multi-Higgs doublet models.

Gravitational interactions
The use of equivalence principles to test relativistic theories of gravity:
-around the Sun;
-in the early Universe.
Projects
Research directions:
Experiments and collaborations:
Active projects
CP and chiral symmetry in K physics.
Jean-Marc Gérard

Study anomalous effect on the energy distribution and try to extract the parameter from experimental data.
Gravitational Wave Physics with Virgo
Diego Bardiaux, Giacomo Bruno, Jan Govaerts, Jean-Marc Gérard, Vincent Lemaitre, Krzysztof Piotrzkowski, Andres Tanasijczuk

In July 2018 CP3 members have joined the Virgo Collaboration at the European Gravitational Observatory (EGO) near Pisa in Italy. Virgo is the European laser interferometer for gravitational wave detection. After several years of instrument upgrades, Virgo went in observation mode in August 2017, about one year and half after the two LIGO interferometers in the US had detected for the first time gravitational waves. Virgo and LIGO work in close collaboration, sharing data, analysing data and publishing together. Fundamental research in gravitational wave experimental physics was funded for the first time in Belgium at the end of 2018 with a project led by UCLouvain and ULiege. On the data analysis side the plan is on one side to investigate the properties of binary black hole coalescence events, possibly relating them to theoretical models of dark matter and/or primordial black holes, and on the other to search for a stochastic gravitational wave background originating from the very early moments of the life of the Universe, a discovery that would be foundational for cosmology. On the instrumentation side, contributions to computing and the optical system of the Virgo interferometer are planned.
CP3 members are also actively supporting the Einstein Telescope project, a proposed underground laser interferometer project for gravitational wave detection that is expected to take over from LIGO and Virgo around 2030.
On the unification of gauge coupling constants
Jean-Marc Gérard

In the standard model version of the grand unified theory different gauge couplings intend to, but do not, meet at some higher scale. Here we will look for some better ways for the unification of the gauge coupling constants.
Scalar-tensor theories of gravitation
Jean-Marc Gérard

The strong equivalence principle (SEP) does not hold anymore in various extensions of General Relativity. Its violations can be revealed by the non-universality of free-falling for compact objects and we have developed a generic and effective way to test the SEP in the Cosmic Microwave Background (CMB). A violation of the SEP indeed alters the amplitude of the acoustic oscillations in the primeval plasma. Using the WMAP data, we have contrained a possible SEP violation for the baryons.

Our interests are also focused on the scalar-tensor theories of gravitation and their cosmologies. In a more specific way, we are currently studying a model where the scalar sector is conformally invariant. The effective fluid related to the non-minimally coupled scalar field differs from the other cosmological fluids of radiation by its very particular anisotropic pressure and we are studying its impact on the CMB anisotropies by modifying the CAMB code.
Tensions in flavor physics and two Higgs doublet models
Jean-Marc Gérard

Study of the tensions observed between the K and the B meson systems and their implications for scalar-mediated flavor changing currents in the framework of two Higgs doublet models (2HDM).

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

Number of publications as CP3 member: 34

Last 5 publications

2018

CP3-18-38: Master formula for $arepsilon'/arepsilon$ beyond the Standard Model
Aebischer, Jason and Bobeth, Christoph and Buras, Andrzej J. and Gérard, Jean-Marc and Straub, David M.

[Abstract] [PDF]
6 pages, 1 table
June 26.
CP3-18-31: BSM Hadronic Matrix Elements for $epsilon'/epsilon$ and $K opipi$ Decays in the Dual QCD Approach
Aebischer, Jason and Buras, Andrzej J. and Gérard, Jean-Marc

[Abstract] [PDF] [Journal] [Dial]
ABJ-18-5
Refereed paper. May 25.
CP3-18-25: Dual QCD Insight into BSM Hadronic Matrix Elements for K0−K¯0 Mixing from Lattice QCD
Buras, Andrzej J. and Gerard, Jean-Marc

[Abstract] [PDF]
17 pages, no figures
March 29.
CP3-18-21: $K\to\pi\pi$ and $K-\pi$ Matrix Elements of the Chromomagnetic Operators from Dual QCD
Buras, Andrzej J. and Gérard, Jean-Marc

[Abstract] [PDF] [Journal] [Dial]
Published in JHEP 1807 (2018) 126
Refereed paper. March 12.

2016

CP3-16-08: Final State Interactions in $K opipi$ Decays: $Delta I=1/2$ Rule vs. $arepsilon^prime/ arepsilon$
Buras, Andrzej J. and Gerard, Jean-Marc

[Abstract] [PDF] [Journal] [Dial]
March 15.

More publications