Anomalous Diffusion in Infinite Horizon Billiards

We consider the long time dependence for the moments of displacement < |r|^q > of infinite horizon billiards, given a bounded initial distribution of particles. For a variety of billiard models we find ~ t^g(q) (up to factors of log t). The time exponent, g(q), is piecewise linear and equal to q/2 for q2. We discuss the lack of dependence of this result on the initial distribution of particles and resolve apparent discrepancies between this time dependence and a prior result. The lack of dependence on initial distribution follows from a remarkable scaling result that we obtain for the time evolution of the distribution function of the angle of a particle's velocity vector.Comment: 11 pages, 7 figures Submitted to Physical Review

Composite electric S-brane solutions with maximal number of branes

In this paper we consider (n+1)-dimensional cosmological model with scalar field and antisymmetric (p+2)-form. Using an electric composite Sp-brane ansatz the field equations for the original system reduce to the equations for a Toda-like system with n(n-1)/2 quadratic constraints on the charge densities. For certain odd dimensions (D = 4m+1 = 5, 9, 13, ...) and (p+2)-forms (p = 2m-1 = 1, 3, 5, ...) these algebraic constraints can be satisfied with the maximal number of charged branes ({\it i.e.} all the branes have non-zero charge densities). These solutions are characterized by self-dual or anti-self-dual charge density forms Q (of rank 2m). For these algebraic solutions with the particular D, p, Q and non-exceptional dilatonic coupling constant \lambda we obtain general cosmological solutions to the field equations and some properties of these solutions are highlighted (e.g. Kasner-like behavior, the existence of attractor solutions). We prove the absence of maximal configurations for p =1 and even D (e.g. for D =10 supergravity models and those of superstring origin).Comment: 19 pages JHEP format, references adde

Spin Correlation Coefficients in pp Elastic Scattering at 200 MeV

This research was sponsored by the National Science Fooundation Grant NSF PHY-931478

Hamiltonian dynamics and Noether symmetries in Extended Gravity Cosmology

We discuss the Hamiltonian dynamics for cosmologies coming from Extended Theories of Gravity. In particular, minisuperspace models are taken into account searching for Noether symmetries. The existence of conserved quantities gives selection rule to recover classical behaviors in cosmic evolution according to the so called Hartle criterion, that allows to select correlated regions in the configuration space of dynamical variables. We show that such a statement works for general classes of Extended Theories of Gravity and is conformally preserved. Furthermore, the presence of Noether symmetries allows a straightforward classification of singularities that represent the points where the symmetry is broken. Examples of nonminimally coupled and higher-order models are discussed.Comment: 20 pages, Review paper to appear in EPJ

Experimental Test of a New Technique to Overcome Spin-Depolarizing Resonances

We recently tested a new spin resonance crossing technique, Kondratenko Crossing (KC), by sweeping an rf-solenoid's frequency through an rf-induced spin resonance with both the KC and traditional fast crossing (FC) patterns. Using both rf bunched and unbunched 1.85 GeV/c polarized deuterons stored in COSY, we varied the parameters of both crossing patterns. Compared to FC with the same crossing speed, KC reduced the depolarization by measured factors of 4.7 +/- 0.3 and 19(-5)(+12) for unbunched and bunched beams, respectively. This clearly showed the large potential benefit of Kondratenko Crossing over fast crossing

Silicon Detector Development for Cooler Exp. 35

This research was sponsored by the National Science Foundation Grant NSF PHY-931478