B-hadrons spectroscopy and decay properties with the ATLAS experiment

The parity violating asymmetry parameter αb in Λb→ΛJ/ψ decay was measured using the ATLAS detector in proton–proton collisions at the Large Hadron Collider at , using data collected in the 2011 run. Furthermore, a search for excited states of the meson was performed using 4.9fb−1 of 7 TeV and 19.2fb−1 of 8 TeV proton–proton collision data. A new state was observed through its hadronic transition to the ground state, with an invariant mass of 6842 ± 7 ± 4 MeV, consistent with predictions for the meson.