Roberto Petronzio

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Several neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's diseases are associated with amyloid fibrils formed by different polypeptides. We probe the structure and stability of oligomers of different sizes of the fragment Abeta(16-22) of the Alzheimer beta-amyloid peptide using atomic-detail molecular dynamics simulations with(More)
We compute charm and bottom quark masses in the quenched approximation and in the continuum limit of lattice QCD.We make use of a step scaling method, previously introduced to deal with two scale problems, that allows to keep the lattice cutoff always greater than the quark mass. We determine the RGI quark masses and make the connection to the MS scheme.(More)
We make a comparison between our quenched-hadron-spectroscopy results for the non-perturbatively-improved Wilson action and the corresponding unimproved case, at β = 6.2 on the same set of gauge configurations. Within our statistics, we find a sizeable improvement for the baryon spectrum and for the determination of the strange-quark mass . CERN-TH/98-110(More)
Roberto Ammendola∗ab, Andrea Biagionic, Ottorino Frezzac, Francesca Lo Ciceroc, Alessandro Lonardoc, Pier Paoluccic, Roberto Petronzioad , Davide Rossettic, Andrea Salamona, Gaetano Salinaa, Francesco Simulae, Nazario Tantaloab, Laura Tosorattoc and Piero Vicinic aINFN Roma Tor Vergata bCentro Studi e Ricerce e Museo della Fisica “Enrico Fermi ” cINFN Roma(More)
We study dynamical fermion effects in lattice QCD at finite temperature. The method adopted is basically the extrapolation from negative flavour numbers already tested at zero temperature and based on the simulation of local bosonic theories, with an essential difference. With an appropriate choice of the boundary conditions on the bosonic fields, called(More)
We present the current status of APENet, our custom 3-dimensional interconnect architecture for PC clusters environment. We report some micro-benchmarks on our recent large installation as well as new developments on the software and hardware side. The low level device driver has been reworked by following a custom hardware RDMA architecture, and MPICH-VMI,(More)
This paper is a slightly modified and reduced version of the proposal of the apeNEXT project, which was submitted to DESY and INFN in spring 2000. It presents the basic motivations and ideas of a next generation lattice QCD (LQCD) computing project, whose goal is the construction and operation of several large scale Multi-TFlops LQCD engines, providing an(More)
We present evidence for the universality of the continuum limit of the scale dependence of the renormalization constant associated with the operator corresponding to the average momentum of non-singlet parton densities. The evidence is provided by a non-perturbative computation in quenched lattice QCD using the Schrödinger Functional scheme. In particular,(More)
We determine non-perturbatively the anomalous dimensions of the second moment of non-singlet parton densities from a continuum extrapolation of results computed in quenched lattice simulations at different lattice spacings. We use a Schrödinger functional scheme for the definition of the renormalization constant of the relevant twist-2 operator. In the(More)
We perform an extrapolation from negative to positive flavour numbers of full QCD lattice estimates of the η′ mass. The extrapolations are carried out by keeping ρ and π masses at fixed values. We find an η′ – π splitting which shows a flavour dependence consistent with the Witten Veneziano formula based on the U(1) anomaly. The quantitative splitting is(More)