A Complete Onium Program with R2D at RHIC II

Following on the discovery of a strongly interacting quark-gluon plasma (QGP) at RHIC, a program of detailed quarkonia measurements is crucial to understanding the nature of deconfinement. Lattice QCD calculations suggest a sequential melting of the quarkonia states in the deconfined medium. Such a melting would lead to a suppression in the measured charmonium and bottomonium yields. However, distinguishing a true suppression from shadowing, absorption, and recombination effects requires detailed measurements of the charmonium states (J/psi, psi', and chi_c) and bottomonium states (Y(1S), Y(2S), and Y(3S)). Also, since measurements are needed not only in A+A, but also in p+p for determining primary yields and in p+A for evaluating absorption, the detector should perform well in all collision environments. To fully realize the program outlined above, a new detector will be required at RHIC-II. We present a proposal for a complete quarkonia program and the abilities of a new detector, R2D, to meet the stated requirements. Comparisons will be made with proposed upgrades to existing RHIC detectors and with the upcoming LHC program.Comment: 3 pages, submitted proceedings from PANIC '0

Trip-Based Public Transit Routing Using Condensed Search Trees

We study the problem of planning Pareto-optimal journeys in public transit networks. Most existing algorithms and speed-up techniques work by computing subjourneys to intermediary stops until the destination is reached. In contrast, the trip-based model focuses on trips and transfers between them, constructing journeys as a sequence of trips. In this paper, we develop a speed-up technique for this model inspired by principles behind existing state-of-the-art speed-up techniques, Transfer Pattern and Hub Labelling. The resulting algorithm allows us to compute Pareto-optimal (with respect to arrival time and number of transfers) 24-hour profiles on very large real-world networks in less than half a millisecond. Compared to the current state of the art for bicriteria queries on public transit networks, this is up to two orders of magnitude faster, while increasing preprocessing overhead by at most one order of magnitude