Astroparticle Seminar

Beyond Standard Model Top Physic through same-charge dilepton

Léa Gauthier

Université de Montréal

The same charge dilepton channel is a good probe for BSM physics at the LHC due to its very low background in the Standard Model. Moreover, this final state is expected in a wide variety of new physics models : Composite Higgs Model, Randall-Sundrum, Supersymetry,... This final state is used here to analyse different exotic models.

Two complementary analyses are presented here:

• the first one is a theoretical analysis studying 4 tops in the final state: four-top production is an interesting final state and a sensitive probe of new physics. A particular model is presented where the top quark is partially composite and a new heavy particle couples strongly to top quark.
• the second one is an experimental analysis with an extradimensional model which includes top partner particles as well as fourth generation quark and four-top production. This analysis includes the first ATLAS results on : a limit on the four-top production cross-section and a limit on the composite model when both pair and single production of the top partner are taken into account.