The study of the Higgs boson pair production is generating a growing interest in the particle physics community, in particular in view of the High-Luminosity phase of LHC. In addition to the Higgs self-coupling, the VVHH coupling is also an important parameter to improve our understanding of the electroweak symmetry breaking, which can be probed through the search for di-Higgs events in the VBF production mode.

The ATLAS detector is ideally suited for such studies, with its design optimised to reconstruct and identify most of the decay products of the Standard Model particles produced in rare physics processes involving Higgs bosons, such as the di-Higgs production modes. This thesis will include some work on the optimisation of the algorithms used to identify jets produced in the hadronization of b-quarks for the upgrade of the ATLAS detector planned for the High-Luminosity phase of the LHC. Those algorithms play a major role in all the final states involving b-quarks, produced in the decay of the top quark and of the Higgs boson for instance. 

Very strong constrains on the VVHH coupling can already be achieved with the LHC Run 3 dataset, in particular combining the low and high m(HH) regions. The corresponding analyses are the focus of a collaborative research effort involving several French laboratories members of the ATLAS Collaboration at CERN. The PhD position would complement this research effort, with a particular focus on the analysis of the bbtautau resolved final state, benefitting from the strong expertise of the ATLAS group at CPPM in b-tagging and di-Higgs studies [1-2].

Applications should include a CV, a letter of motivation, academic records from bachelor to master and contacts of two reference persons willing to provide reference letters.

[1] ATLAS flavour-tagging algorithms for the LHC Run 2 pp collision dataset https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/FTAG-2019-07/

[2] Search for Higgs boson pair production in the final state with two bottom quarks and two photons in pp collisions at ?s = 13 TeV with the ATLAS detector https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HDBS-2018-34/