ATLAS: helicity analyses in beauty hadron decays

The ATLAS detector will allow a precise spatial reconstruction of the kinem atics of B hadron decays. In combination with the efficient lepton identifi cation applied already at trigger level, ATLAS is expected to provide large samples of exclusive decay channels cleanly separable from background. The se data sets will allow spin-dependent analyses leading to the determinatio n of production and decay parameters, which are not accessible if the helic ity amplitudes are not separated. Measurement feasibility studies for decay s B-s(0) --> J/psi phi and Lambda(b)(0) --> Lambda J/psi, presented in this document, show the experimental precisions that can be achieved in determi nation of B-s(0) and Lambda(b)(0) characteristics. (C) 2000 Elsevier Scienc e B.V. All rights reserved.