Extracting Parameters of Nature at the LHC (and beyond)
Given that the new physics is separated from the SM via a mass gap and cannot be produced directly, its effects can be described via operators of mass dimension D > 4 (composed of SM fields), parametrizing deviations from the SM in a 'model-independent' way - in analogy to the Fermi theory. Constraining the coefficients of these effective field theory (EFT) operators by combining information from various directions will deliver important insights on how the SM could be completed at high energies.
While for example several properties of the Higgs boson are already measured with reasonable accuracy, very little is known so far about its Yukawa couplings to light fermions, its self couplings (extractable via Higgs-pair production) and its effective coupling to a Z boson and a photon. Learning more about these interactions is however of paramount importance for a deep understanding of the Higgs sector. The research group is also working on novel approaches to extract such couplings in an EFT approach, proposing for example new channels or methods to constrain them (such as in [1-5]).
[1] I. Brivio, FG, G. Isidori, PRL 115 (2015), 211801
[2] FG, PRL 113 (2014), 261803
[3] FG, Papaefstathiou, Yang, Zurita, JHEP 1306 (2013) 016
[4] FG, Papaefstathiou, Yang, Zurita, JHEP 1504 (2015) 167
[5] Dall’Osso, Dorigo, FG, Gottardo, Oliveira, Tosi, JHEP 04 (2016) 126