arXiv subjects
Publications and source records attributed to M. Franco Sevilla.
The Upstream Tracker is a new, high-precision silicon strip detector installed in the LHCb experiment as part of the overall LHCb Upgrade I project. The detector is an integral part of the tracking system, and plays a crucial role in the reconstruction of charged particles in the new fully software-based trigger. An overview of the Upstream Tracker detector design, its commissioning, and performance are presented.
We describe searches for B meson decays to the charmless vector-vector final states omega omega and omega phi with 471 x 10^6 B Bbar pairs produced in e+ e- annihilation at sqrt(s) = 10.58 GeV using the BABAR detector at the PEP-II collider at the SLAC National Accelerator Laboratory. We measure the branching fraction B(B0 --> omega omega) = (1.2 +- 0.3 +0.3-0.2) x 10^-6, where the first uncertainty is statistical and the second is systematic, corresponding to a significance of 4.4 standard deviations. We also determine the upper limit B(B0 --> omega phi) < 0.7 x 10^-6 at 90% confidence level. These measurements provide the first evidence for the decay B0 --> omega omega, and an improvement of the upper limit for the decay B0 --> omega phi.