I am an Astroparticle physicist. This means that I work at the interface of particle physics, astrophysics and cosmology. The results of e.g. WMAP and Planck experiments relieved that about 80% of the matter content of the Universe is invisible. My job is to determine what this "dark" matter is made of. Discovering new particles for example would most likely reveal new fundamental laws in the Universe.
I obtained my PhD at Ecole Normale Superieure (Paris) in 2001, under the official supervision of Prof P. Fayet (and unofficial supervision of Prof R. Schaeffer at CEA, Saclay).
In 2001, I was awarded a national fellowship in the UK to work with Prof J. Silk at Oxford University and, in 2004, another fellowship to work in the theory division at CERN.
At the same epoch, I was recruited at the french national institute for research (CNRS) and became a permanent staff member at LAPTH, Annecy (a beautiful town, definitely worth a visit if you do not know it yet!). After a few years spent in a laboratory overlooking the Mont Blanc (almost!), I joined the Institute for Particle Physics Phenomenology at Durham University. The view is not quite the same but I enjoy working in a University environment and meeting bright students.
Field of expertise
My research involves:
- Dark matter physics,
- Beyond the Standard Model theories,
- The Cosmic Microwave Background and large-scale-structure formation,
and sometime a combination of all of these at the same time.
Most of my work lies at the frontier of theoretical and experimental physics. One aspect of my job is to predict the signatures associated with theoretical dark matter models and identify the best strategy to detect these effects in particle and cosmology experiments. Another facet of my work is to use the results of experimental searches to confirm or rule out current theories of our Universe.
During my PhD I worked with A. Djouadi and M. Drees on supersymmetry. With Y. Mambrini and A. Djouadi, we were the first to compute and predict the
4-body decay of the stop (the supersymmetric partner of the top) see hep-ph/9907428 , a process that was used to search for at LHC and, with A. Djouadi & M Drees, to study the coannihilations between the neutralino and the supersymmetric partner of the top, one of the rare process that maintains the neutralino dark matter hypothesis still alive ( hep-ph/9911496 ). I have continued my research in supersymmetry since from the dark matter point of you and the Higgs boson too (see for example 1203.3446 and 1303.5386).
I have also pioneered the notion of collisional damping with R. Schaeffer and P. Fayet, i.e. the impact of dark matter interactions with itself and Standard Model particles on the Cosmic Microwave Background and the formation of the large-scale-structures in the Universe. Recently, thanks to a collaboration between several members at Durham University, we showed that not only can dark matter interactions in the early Universe have a huge impact on the number of small structures but they can also transform our cosmic neighbourhood completely ( 1404.7012 ). This is essentially a new way to set limits on dark matter interactions. I expect big galaxy surveys to play a leading role in constraining the dark matter microphysics, as explained here. A little movie to illustrate the impact of dark matter interactions with photons (or neutrinos) was made by J. Schewtschenko and is shown below
This work led me to introduce light dark matter particles with T. Ensslin & J. Silk (with a mass smaller than 10 GeV to avoid gamma-ray constraints, astro-ph/0208458) coupled to light Z' and, a bit later with P. Fayet, to introduce simplified models to study the phenomenology of light dark matter models ( hep-ph/0305261). It all became fascinating when SPI on board of the SPI satellite announced the detection of a 511 keV line in the Galactic Centre (GC), which they could attribute to the formation of positronium (and therefore the existence of low energy positrons in the GC). This led me and my collaborators to assume that this signal could come from light dark matter particles (astro-ph/0309686). Since this work, I have continued to seek for dark matter signatures in the sky. These works include efforts to assess the dark matter density profile in the galactic centre and M87. I was also intrigued by the so called "GeV excess" seen in the Fermi-LAT data of the Galactic centre. The work published on this subject with e.g. my former postdoc, Dr C. McCabe, and a current PhD student, T. Lacroix can be found in 1401.6458, 1403.1987, 1404.4977.
In the last few years, I had also a close look at the data analysis of the CoGeNT and Xenon100 experiments with my collaborators (in particular my former PhD student Dr J. Davis). We showed for example that the excess found by the CoGeNT collaboration was likely to be due to a possible misinterpretation of the background events, as explained in 1405.0495. This work was made possible because CoGeNT was the first dark matter direct detection experiment to make their data public. This courageous move was in my opinion a huge step forward, as discussed in an article by Jon Cartwright and another by Jon Butterworth.
Astroparticle physics aside, I have interest in biology and in fact have published two papers in collaboration with Prof R. Twarock and Dr P.-P. Dechant on the affine extension of non-crystallographic Coxeter groups (see 1110.5228 and 1110.5219 ), which is relevant to describe the surface organisation of viruses that cannot be described by the Caspar-Klug theory.
For more of my work, see my list of publications in InSPIRE-hep.
Supervision of PhD students
- 2014- : T. Jubb,
- 2013-2016: R. Wilkinson, our papers can be found here
- 2012-2016: T. Lacroix, here
- 2011-2014: J. Davis, here
- 2008-2011: D. Albornoz-Vasquez, here
Supervision of PhD students on SPECIFIC PROJECTS
- 01-06 2015, Maria de Los Angeles Moline, supervisor Dr S. Palomares-Ruiz
- 2013-2016, Jascha Schewtschenko, supervisor Profs C. Baugh and S. Pascoli
- 01-06 2012, Jonathan DaSilva, supervisor Prof G. Belanger
- 2011-2014, Ernestas Pukartas, supervisor Dr A. Mazumdar
Supervision of Postdoctoral fellows
- From 2014, Dr Aaron Vincent
- 2011-2014, Dr Christopher McCabe
- 2012-2014, Dr Takashi Toma (with Prof S. Pascoli)
- 2011-2013, Dr Pierre Dechant (with Prof R. Twarock)