B-Physics and Quarkonium studies in early ATLAS data

B-Physics and Quarkonia physics are among the first areas to be investigated with the first data collected by ATLAS. In the following we present the related physics program planed for the early period of LHC. Investigation of the decay of B-hadrons represents an alternative approach to direct searches for Physics beyond the Standard Model. The ATLAS efforts concentrate on those B decays that can be selected by the first and second trigger levels. The most favorable B and heavy quarkonia trigger signatures will be events decaying to μ pair, either directly or via a J/psi meson. Using the J/psi trigger ATLAS will be able to collect unprecedentedly high statistics of Bs‐>J/ψφ decays, allowing measurements of CP violating effects, which are predicted by some Beyond the SM to be significantly larger than the Standard Model. The di-muon trigger will also give ATLAS access to potentially large numbers of rare B-> mumu decays. Early B-physics data will provide valuable information on the detector performance, as well as allow calibration studies in support of New Physics searches. Meaningful quarkonium studies performed with early data are expected to have the reach to make authoritative statements about the underlying production mechanism and provide cross-sections in this new energy regime.