123370608
Computing technology and environment for physics research
Over the past year a remarkable progress in computing technology and environment for physics research has been achieved. This article tries to summarize the contributions to the field as presented in the course of the ACAT2003 conference.
122322573
New states as observed by the Crystal Barrel experiment
Abstract The Crystal Barrel Detector has been in operation since October 1989. Results on the analysis of the annihilation of protonium at rest into three pseudoscalars is presented. The π 0 π 0 π 0 final state confirms the existence of ƒ 2 (1520)→π 0 π 0 . In the ηη system of the π 0 ηη final state an isoscalar J PC = 0 ++ resonance with a mass of 1560 MeV/c 2 and a width of 245 MeV/c 2 is observed. The identification with ƒ 0 (1590) is doubtful since the ηη' decay is not observed with the corresponding strength. Our analysis yields an upper limit for the relative branching ratio BR(ƒ 0 (1560)→ηη') BR(ƒ 0 (1560)→ηη) .
121889238
Antiproton-proton annihilation at rest into two mesons
Abstract Branching ratios for antiproton-proton annihilations at rest into two mesons are given. The data were obtained at LEAR by stopping antiprotons in a liquid hydrogen target. Both charged and neutral annihilation products were detected in the Crystal Barrel detector. Representative data are presented, and their bearing on the general picture of annihilation dynamics is discussed. In addition, preliminary branching ratios for two-body radiative annihilations are given.
54028825
Dynamic Extensions of Batch Systems with Cloud Resources
Compute clusters use Portable Batch Systems (PBS) to distribute workload among individual cluster machines. To extend standard batch systems to Cloud infrastructures, a new service monitors the number of queued jobs and keeps track of the price of available resources. This meta-scheduler dynamically adapts the number of Cloud worker nodes according to the requirement profile. Two different worker node topologies are presented and tested on the Amazon EC2 Cloud service.
53706779
Spectroscopy of Light Quark Systems
Thi s article i s part of a proposal for the construction of a high intensity proto~ accelerator in Europe (EHF, Proposal for a European Hadron Facility, edited by J.F.Crawford (SIN), supported by BMFT (Germany) and INFN (Italy)). Experiments concerning the spectroscopy of light Quark systems are discussed, which can be performed wi th Kaon beams of high intensi ty and high purity at EHF. After abrief review of the status of Mesonand Baryonspectroscopy an optimized detection system is presented, and two specific experiments (Glue-Ball production with Kbeams; radiative decays of the A(1405)-resonance) are discussed in detail. A Monte-Carlo-simulation shows, that clear signals for these processes can be obtained in short measuring times. These examples demonstrate, that wi th high quali ty Kbeams new and important information on Hadron-spectroscopy can be obtained, which is important for a further understanding of Quantum-Chromo-Dynamics.
122284184
Parametric optimization with evolutionary strategies in particle physics
Abstract Evolutionary strategies provide a generic means to find optimum solutions for large-scale numerical problems. The EVA library, an implementation of parallel Evolutionary Algorithms, adds the possibility to run the optimization in parallel on devices ranging from multi-processor machines over clusters to the world wide grid. This paper discusses the application of the EVA library to two distinct computationally expensive physics problems—the optimization of particle signals in histograms and the minimization procedure involved in analysing Dalitz plots.
53967767
Existence of Axially Symmetric Static Solutions of the Einstein-Vlasov System
We prove the existence of static, asymptotically flat non-vacuum spacetimes with axial symmetry where the matter is modeled as a collisionless gas. The axially symmetric solutions of the resulting Einstein-Vlasov system are obtained via the implicit function theorem by perturbing off a suitable spherically symmetric steady state of the Vlasov-Poisson system.
16238417
Gravitational collapse and the formation of black holes for the spherically symmetric Einstein-Vlasov system
We review results on the spherically symmetric, asymptotically flat Einstein-Vlasov system. We focus on a recent result where we found explicit conditions on the initial data which guarantee the formation of a black hole in the evolution. Among these data there are data such that the corresponding solutions exist globally in Schwarzschild coordinates. We put these results into a more general context, and we include arguments which show that the spacetimes we obtain satisfy the weak cosmic censorship conjecture and contain a black hole in the sense of suitable mathematical definitions of these concepts which are available in the literature.
8009241
Simplified models of electromagnetic and gravitational radiation damping
In previous work the authors have analysed the global properties of an approximate model of radiation damping for charged particles. This work is put into context and related to the original motivation of understanding approximations used in the study of gravitational radiation damping. We examine to what extent the results obtained previously depend on the particular model chosen. Comparisons are made with other models for gravitational and electromagnetic fields. The relation of the kinetic model for which theorems were proved to certain many-particle models with radiation damping is exhibited.
6557807
Global Existence for the Spherically Symmetric Einstein–Vlasov System with Outgoing Matter
We prove a new global existence result for the asymptotically flat, spherically symmetric Einstein–Vlasov system which describes in the framework of general relativity an ensemble of particles which interact by gravity. The data are such that initially all the particles are moving radially outward and that this property can be bootstrapped. The resulting non-vacuum spacetime is future geodesically complete.