The LHC's Atlas collaboration at Cern has observed a rare process: the production of Higgs bosons in association with a top quark and top antiquark pair. This work, supervised by an Irfu researcher, opens up perspectives on the study of the Higgs mechanism that gives mass to particles.
A particle-antiparticle pair is all the more likely to interact with a Higgs boson since this particle is massive. And yet, the top quark is the most massive particle in the Standard Model of particle physics. This is why physicists are interested in the LHC's "events", which associate the Higgs boson and top quarks. The production of a Higgs boson following the production of a top quark - top antiquark pair is the sign of an interaction or coupling between the Higgs boson and the top quark. This particularly strong coupling is therefore interesting to study in order to shed light on the Higgs mechanism.
The LHC's Atlas collaboration recently made public two Higgs boson disintegration pathways, one reasonably probable but strongly "noisy" due to an interfering mechanism, whereas the other is more rare but also more "clean". It is the latter pathway that has allowed physicists to obtain the most significant result, taking into account the current post-processing capabilities of the data. The researchers are not yet speaking of results since the quantity of data is not quite sufficient, although the presumption is strong: the recently obtained value agrees well with the Standard Model's prediction.
This study is based on data recorded in 2015 and 2016 at 13 TeV of proton-proton collision energy.
Contact : Henri Bachacou