Observation and first properties measurements of the Higgs boson candidate in its di-photon decay with the ATLAS experiment

by Marine Kuna (INFN Roma)

Thursday 4 Jul 2013, 16:00 → 17:30 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

Last July 4, the discovery of an excellent Higgs boson candidate around 125 GeV in the collision data provided by the LHC at CERN was announced. A year later, the observed excess using the full statistics provided by the collider reaches 7.4 standard deviations in the ATLAS di-photon channel alone. Aiming to contribute to the confirmation or disclaimer that this newly discovered particle is the Standard Model Higgs boson, the gamma gamma analysis has been re-optimised towards properties measurements. The boson’s mass determination will be presented, as well as preliminary results on its spin from the Standard Model spin-0 hypothesis confrontation with a graviton-like spin-2 model with minimal couplings. The signal strength in the di-photon channel is currently measured to be larger than the SM predictions. Its breaking down into the contributions from different production modes has been performed to allow a better understanding of the particle’s coupling with the top quark and the W and Z vector bosons.

Slides SeminarRome_04-06-13_last.pdf