Latest Results from PHOBOS

This manuscript contains a summary of the latest physics results from PHOBOS, as reported at Quark Matter 2006. Highlights include the first measurement from PHOBOS of dynamical elliptic flow fluctuations as well as an explanation of their possible origin, two-particle correlations, identified particle ratios, identified particle spectra and the latest results in global charged particle production.Comment: 9 pages, 7 figures, PHOBOS plenary proceedings for Quark Matter 200

Planet Tours

Introduction: Planning to take a vacation soon? Visit Phobos! Small and cozy, Phobos orbits the fourth planet from the Sun in less than eight hours. From your observation deck on Phobos, you will have a superb view of Mars. You will see its mountains, polar ice caps, and the largest volcano in the solar system. Call your cosmic travel agent today! Try this creative activity to help your students explore the solar system in an imaginative manner.McDonald Observator

Advancing Tests of Relativistic Gravity via Laser Ranging to Phobos

Phobos Laser Ranging (PLR) is a concept for a space mission designed to advance tests of relativistic gravity in the solar system. PLR's primary objective is to measure the curvature of space around the Sun, represented by the Eddington parameter $\gamma$, with an accuracy of two parts in $10^7$, thereby improving today's best result by two orders of magnitude. Other mission goals include measurements of the time-rate-of-change of the gravitational constant, $G$ and of the gravitational inverse square law at 1.5 AU distances--with up to two orders-of-magnitude improvement for each. The science parameters will be estimated using laser ranging measurements of the distance between an Earth station and an active laser transponder on Phobos capable of reaching mm-level range resolution. A transponder on Phobos sending 0.25 mJ, 10 ps pulses at 1 kHz, and receiving asynchronous 1 kHz pulses from earth via a 12 cm aperture will permit links that even at maximum range will exceed a photon per second. A total measurement precision of 50 ps demands a few hundred photons to average to 1 mm (3.3 ps) range precision. Existing satellite laser ranging (SLR) facilities--with appropriate augmentation--may be able to participate in PLR. Since Phobos' orbital period is about 8 hours, each observatory is guaranteed visibility of the Phobos instrument every Earth day. Given the current technology readiness level, PLR could be started in 2011 for launch in 2016 for 3 years of science operations. We discuss the PLR's science objectives, instrument, and mission design. We also present the details of science simulations performed to support the mission's primary objectives.Comment: 25 pages, 10 figures, 9 table

Two-particle angular correlations in p+p and Cu+Cu collisions at PHOBOS

We present results on two-particle angular correlations in p+p and Cu+Cu collisions over a broad range of ($\eta$,$\phi$). The PHOBOS detector has a uniquely large angular coverage for inclusive charged particles. This allows for the study of correlations on both long and short range pseudorapidity scales. A complex two-dimensional correlation structure emerges which is interpreted in the context of a cluster model. The cluster size and its decay width are extracted from the two-particle pseudorapidity correlation function. Relative to p+p collisions, Cu+Cu reactions show a non-trivial decrease of cluster size with increasing centrality. These results may provide insight into the hadronization stage of the hot and dense medium created in heavy ion collisions.Comment: 5 pages, 4 figures, presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2006", Shanghai, China, November 14-20, 200