Search results for "Lattic"

Hadronic light-by-light contribution to $(g-2)_\mu$ from lattice QCD with SU(3) flavor symmetry

2020

We perform a lattice QCD calculation of the hadronic light-by-light contribution to $(g-2)_\mu$ at the SU(3) flavor-symmetric point $m_\pi=m_K\simeq 420\,$MeV. The representation used is based on coordinate-space perturbation theory, with all QED elements of the relevant Feynman diagrams implemented in continuum, infinite Euclidean space. As a consequence, the effect of using finite lattices to evaluate the QCD four-point function of the electromagnetic current is exponentially suppressed. Thanks to the SU(3)-flavor symmetry, only two topologies of diagrams contribute, the fully connected and the leading disconnected. We show the equivalence in the continuum limit of two methods of computin…

Biased graph walks for RDF graph embeddings

2017

Knowledge Graphs have been recognized as a valuable source for background information in many data mining, information retrieval, natural language processing, and knowledge extraction tasks. However, obtaining a suitable feature vector representation from RDF graphs is a challenging task. In this paper, we extend the RDF2Vec approach, which leverages language modeling techniques for unsupervised feature extraction from sequences of entities. We generate sequences by exploiting local information from graph substructures, harvested by graph walks, and learn latent numerical representations of entities in RDF graphs. We extend the way we compute feature vector representations by comparing twel…

Lattice Boltzmann Simulations at Petascale on Multi-GPU Systems with Asynchronous Data Transfer and Strictly Enforced Memory Read Alignment

2015

The lattice Boltzmann method is a well-established numerical approach for complex fluid flow simulations. Recently general-purpose graphics processing units have become accessible as high-performance computing resources at large-scale. We report on implementing a lattice Boltzmann solver for multi-GPU systems that achieves 0.69 PFLOPS performance on 16384 GPUs. In addition to optimizing the data layout on the GPUs and eliminating the halo sites, we make use of the possibility to overlap data transfer between the host CPU and the device GPU with computing on the GPU. We simulate flow in porous media and measure both strong and weak scaling performance with the emphasis being on a large scale…

Quasiparticle properties of nonequilibrium gluon plasma

2018

We apply classical gluodynamics to early stages of ultrarelativistic heavy-ion collisions. We start by giving a brief overview of QCD. Then we proceed to the space-time evolution of ultrarelativistic heavy-ion collisions in the color glass condensate framework and go through the basics of real-time gluodynamics on the lattice in the temporal gauge. We study the plasmon mass scale in three- and two-dimensional systems by comparing three different methods to measure the mass scale. The methods are a formula which can be derived from Hard Thermal Loop effective theory at leading order (HTL), the effective dispersion relation (DR) and measurement of the plasma oscillation frequency triggered by th…

L'aroma del Puzzone

2010

Mantenere la tipicità in un mondo che cambia

2011

Measurement of the top quark charge in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

2013

A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb[superscript −1] of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton t[¯ over t] candidate events. This excludes models that propose a heavy quark of electric charge −4/3, instead of the Standard Model top quark, with a significance of more than 8σ.

"Table 3" of "Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in $pp$ collisions at $\sqrt{s} =13$ TeV wi…

2020

Acceptance times selection efficiency for Kaluza-Klein gluon Γ=30% as a function of top-quark pair mass for all regions A–D in the resolved analysis and the combination of all SRs in the boosted analysis.

"Table 20" of "Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in $pp$ collisions at $\sqrt{s} =13$ TeV w…

2020

Expected and observed upper limits on the cross-section times branching fraction of Kaluza-Klein gluon decaying into top-quark pair as a function of the gluon mass.

K°- K°, - D° and B° - B° oscillations in the Standard Model and beyond from unquenched Twisted Mass Lattice QCD

2013

El análisis del triángulo de unitariedad y la búsqueda de cotas restrictivas sobre las escala de nueva física requiere medidas precisas de las amplitudes de mezcla de las oscilaciones de mesones. El retículo proporciona una óptima herramienta no perturbativa para el cálculo de dichos elementos de matriz con incertidumbres del 1% y errores sistemáticos bajo control. La tesis se centra en el cálculo de los parámetros B, que controlan las oscilaciones de mesones, la masa del quark b y las constantes de desintegración fB y fBs a partir de QCD simulada en el retículo con fermiones Twisted Mass e incluyendo los efectos cuánticos de quarks dinámicos en el mar. A lo largo de esta tesis, a partir de…