Matteo Beccaria

Radiative correction effects of a very heavy top

Abstract If the top is very heavy, mt ⪢ Mz, the dominant radiative correction effects in all electroweak precision tests can be exactly characterized in terms of two quantities, the ϱ-mparameter and the GIM-violating Z → b b coupling. These quantities can be computed using the standard model lagrangian with vanishing gauge couplings. This is done here up to two loops for arbitrary values of the Higgs mass.

Two loop heavy top effects in the Standard Model

Abstract We give a detailed description of the calculation in the Standard Model of all the m t 4 radiative correction effects to the electroweak precision observables for arbitrary values of the Higgs mass.

Kramers equation simulation algorithm. I. Operator analysis.

Using an operatorial formalism, we study the Kramers equation and its applications to numerical simulations. We obtain classes of algorithms which may be made precise at every desired order in the time step ǫ and with a set of free parameters which can be used to reduce autocorrelations. We show that it is possible to use a global Metropolis test to restore Detailed Balance.

Kramers equation simulation algorithm. II. Application to the Gross-Neveu model.

We continue the investigation on the applications of the Kramers equation to the numerical simulation of field theoretic models. In a previous paper we described the theory and proposed various algorithms. Here, we compare the simplest of them with the hybrid Monte Carlo algorithm studying the two-dimensional lattice Gross-Neveu model. We used a Symanzik-improved action with dynamical Wilson fermions. Both the algorithms allow for the determination of the critical mass. Their performances in the definite phase simulations are comparable with the hybrid Monte Carlo algorithm. For the two methods, the numerical values of the measured quantities agree within the errors and are compatible with the theoretical predictions, moreover; the Kramers algorithm is safer from the point of view of numerical precision.

High-performance road-vehicle optimised aerodynamic design: Application of parallel computing to car design

Abstract The HIPEROAD project has developed a software system capable of performing a semi-automatic optimisation of the shape of sport cars with respect to their aerodynamical properties. The system utilises an aerodynamic solver implemented on parallel MIMD systems, and features advanced tools for the evolution and meshing of car surfaces. The system allows one to include aerodynamic optimisation in the early stages of car design. It has been tested on a Ferrari auto model and full agreement between computed and measured aerodynamical properties was found. The code has been used for designing an optimised model with improved car safety.

Continuum limit of field theories regularized on a random lattice

The continuum limit and scaling properties of an asymptotically free field theory regularized on a random lattice are compared with those on a regular square lattice. We work on random lattices parametrized by a degree of “randomness” κ. We show that the continuum limit exists and different κ are related by a finite renormalization.

HIgh PErformance ROADvehicle Optimized Aerodynamic Design: Application of Parallel Computing to Car Design

The HIPEROAD project has developed a software system capable of performing a semi-automatic optimisation of the shape of sport cars with respect to their aerodynamical properties. The system utilises an aerodynamic solver implemented on parallel MIMD systems, and features advanced tools for the evolution and meshing of car surfaces. The system allows to include aerodynamic optimisation in the early stages of car design. It has been tested on a Ferrari Auto model and full agreement between computed and measured aerodynamical properties was found. The code has been used for designing an optimised model with improved car safety, reducing the vertical upload significantly without affecting car performance.

Validation and Performance Analysis of a Parallel Ported Code for Simulating the Effects of Lightning Strokes on Telecommunication Buildings

The Artemis subproject, in the framework of the UE Capri project, deals with porting on parallel architectures of a Method of Moment (MoM) code for electromagnetic design and hardening of telecommunication centres against the effects of lightning strokes. After a preliminary stage of the work during which QR and LU algorithms for large complex matrix inversion were implemented both on Alenias Quadrics (SIMD) and Cray T3D (MIMD) platforms, in order to choose the best suitable machine for such a kind of problem, the code has been ported on the last one. In this paper the parallel code validation and the performance improvement analysis with respect to the sequential one will be reported and discussed.

Triggering and data analysis for the VIRGO experiment on the APEmille parallel computer

We give a brief resume of some possible strategies for the real-time data analisys in the framework of the VIRGO experiment. We discuss in particular the utility and the feasibility of their implementation on parallel computers, focusing on the APEmille SIMD machine. We evaluate the computational power required in two cases: the monitoring of known pulsars and the detection of binary coalescences.

Porting on Parallel Platforms of a Tool for Simulating the Effects of Lightning Strokes on Telecommunication Buildings: A Comparison on Preliminary Results about Performances and Accuracy on SIMD and MIMD Architectures

In the framework of the UE CAPRI project, the Artemis subproject deals with porting on parallel architectures of a Method of Moment (MoM) code for electromagnetic design and hardening of telecommunication centres against the effects of lightning strokes.