1,721,120 research outputs found
APEmille
No full textThis paper describes the APEmille project, jointly carried out by INFN and DESY. It mainly focuses on the architectural features of this massively parallel compute engine that matches the computational requirements of LGT. In the paper I briefly cover the story of the APE projects, discuss the requirements of any efficient LGT engine and finally describe the APEmille machine
H- Stripping In Collisions With Low-energy Pbar and H-
No full textElectron detachment of H- by impact of low-energy antiprotons and H- is studied. Detachment cross sections for relative velocities v0.1c are evaluated with the use of several approximations. Results of different methods of calculation are consistent with each other. Cross sections of about 10-14 cm2 are obtained just above the detachment threshold. © 1983 The American Physical Society
Calcolatori: Hardware
No full textSOMMARIO: 1. Introduzione. ▭ 2. Il calcolatore con memoria ad accesso random: a) architettura; b) organizzazione elementare. ▭ 3. Contesto evolutivo. ▭ 4. Evoluzione del processore. ▭ 5. Evoluzione del sistema di memoria. ▭ 6. Prospettive. ▭ Bibliografia
CONTRIBUTION OF HARD QCD INTERACTIONS TO THE PPBAR-PP TOTAL INELASTIC CROSS-SECTION DIFFERENCE AT THE CERN ISR ENERGIES
No full textRelativistic dissipation obeys Chapman-Enskog asymptotics: Analytical and numerical evidence as a basis for accurate kinetic simulations
No full textWe present an analytical derivation of the transport coefficients of a relativistic gas in (2+1) dimensions for both Chapman-Enskog (CE) asymptotics and Grad's expansion methods. We further develop a systematic calibration method, connecting the relaxation time of relativistic kinetic theory to the transport parameters of the associated dissipative hydrodynamic equations. Comparison of our analytical results and numerical simulations shows that the CE method correctly captures dissipative effects, while Grad's method does not, in agreement with previous analyses performed in the (3+1)-dimensional case. These results provide a solid basis for accurately calibrated computational studies of relativistic dissipative flows
IS WEAK INTERACTION SYMMETRY BROKEN BY ORDINARY COLOR FORCES
No full textWe comment on models in which the Weinberg-Salam symmetry is dynamically broken by colour forces. These models have one weak doublet of colour-sextet fermions. Experimental implications of this scheme are studied and compared with predictions of the standard GWS model. © 1983
ON MODELS OF WEAK INTERACTION SYMMETRY-BREAKING BY COLOR FORCES
No full textComments are made on models in which the Weinberg-Salam symmetry is broken by colour forces. In particular, we discuss the relevance of compositeness of quarks, leptons and new fermions (including a family of colour sextets). © 1983
Probing bulk viscosity in relativistic flows
No full textWe derive an analytical connection between kinetic relaxation rate and bulk viscosity of a relativistic fluid in d spatial dimensions, all the way from the ultra-relativistic down to the near non-relativistic regime. Our derivation is based on both Chapman-Enskog asymptotic expansion and Grad's method of moments. We validate our theoretical results against a benchmark flow, providing further evidence of the correctness of the Chapman-Enskog approach; we define the range of validity of this approach and provide evidence of mounting departures at increasing Knudsen number. Finally, we present numerical simulations of transport processes in quark-gluon plasmas, with special focus on the effects of bulk viscosity which might prove amenable to future experimental verification. This article is part of the theme issue 'Fluid dynamics, soft matter and complex systems: recent results and new methods'
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