B-hadrons spectroscopy and decay properties with the ATLAS experiment

ATLAS has performed searches for heavy hadrons, with results including the first observation of the $\chi_b$(3P) Bottomonium states. Also ATLAS studies of B-hadron decays are reviewed, including the measurement of the parity violating asymmetry parameter $\alpha_b$ in $\Lambda_b \rightarrow \Lambda ~J/\psi$, obtained from the study of angular correlations in the $p~\pi^-\mu^+\mu^-$ final state. The measurement is compared to predictions based on perturbative QCD and heavy quarks effective theory.