Search results for "PDF"

Parton distributions and lattice QCD calculations: A community white paper

2018

Progress in particle and nuclear physics 100, 107 - 160 (2018). doi:10.1016/j.ppnp.2018.01.007

Hadroproduction of open heavy flavour for PDF analyses

2019

Due to the large masses of the charm and bottom quarks, their production cross sections are calculable within the perturbative QCD. This makes the heavy-quark mesons important observables in high-energy collisions of protons and nuclei. However, the available calculations for heavy-flavored-meson hadroproduction have been somewhat problematic in reliably describing the cross sections across the full kinematic range from zero to very high $p_{\rm T}$. This has put some question marks on the robustness of LHC heavy-flavored-meson measurements in studying the partonic structure of the colliding hadrons and nuclei. Here, we introduce SACOT-$m_{\rm T}$ - a novel scheme for open heavy-flavour had…

Nuclear PDF constraints from p+Pb collisions at the LHC

2015

As the current nuclear PDF analyses are mainly constrained by fixed-target Drell-Yan and deeply inelastic scattering data only the quark nuclear modifications at fairly large $x$ values are in a good control. Inclusive pion production in d+Au collisions at RHIC provides some constraints for gluons but due to the limited kinematic reach of the data the gluon modifications remain uncertain especially at small values of $x$. In this talk, we discuss how the existing data from p+Pb collisions at the LHC can improve the nuclear PDF fits and which measurements would be sensitive to the small-$x$ gluons. In particular, we consider inclusive hadron production, compare this to direct photons, and sh…

Lévy processes in bounded domains: path-wise reflection scenarios and signatures of confinement

2022

We discuss an impact of various (path-wise) reflection-from-the barrier scenarios upon confining properties of a paradigmatic family of symmetric $\alpha $-stable L\'{e}vy processes, whose permanent residence in a finite interval on a line is secured by a two-sided reflection. Depending on the specific reflection "mechanism", the inferred jump-type processes differ in their spectral and statistical characteristics, like e.g. relaxation properties, and functional shapes of invariant (equilibrium, or asymptotic near-equilibrium) probability density functions in the interval. The analysis is carried out in conjunction with attempts to give meaning to the notion of a reflecting L\'{e}vy process…

Anomalous diffusion and nonlinear relaxation phenomena in stochastic models of interdisciplinary physics

2020

The study of nonlinear dynamical systems in the presence of both Gaussian and non-Gaussian noise sources is the topic of this research work. In particular, after shortly present new theoretical results for statistical characteristics in the framework of Markovian theory, we analyse four different physical systems in the presence of Levy noise source. (a) The residence time problem of a particle subject to a non-Gaussian noise source in arbitrary potential profile was analyzed and the exact analytical results for the statistical characteristics of the residence time for anomalous diffusion in the form of Levy flights in fully unstable potential profile was obtained. Noise enhanced stability …

Interpreting Heterogeneous Geospatial Data Using Semantic Web Technologies

2016

International audience; The paper presents work on implementation of semantic technologies within a geospatial environment to provide a common base for further semantic interpretation. The work adds on the current works in similar areas where priorities are more on spatial data integration. We assert that having a common unified semantic view on heterogeneous datasets provides a dimension that allows us to extend beyond conventional concepts of searchability, reusability, composability and interoperability of digital geospatial data. It provides contextual understanding on geodata that will enhance effective interpretations through possible reasoning capabilities. We highlight this through …

Elektronisko parakstu īstenošana PDF dokumentos

2015

Šis darbs apskata elektronisko parakstu īstenošanu PDF dokumentos. Tas pēta elektronisko parakstu struktūru un funkcionalitāti. Darba mērķis ir izpētīt elektronisko parakstu standartus PDF dokumentiem, struktūru, darbības principus un īstenošanas iespējas. Uzmanība tiek pievērsta pakarstu struktūrai, un ir apskatīti nepieciešamie dati elektronisko parakstu veidošanai. Tiek izpētīti papildus procesi un servisi, kurus ir nepieciešams nodrošināt elektronisko parakstu sniedzēju pusē. Papildus tiek apskatīti dažu elektronisko parakstu sniedzēju produkti. Darbā tiek aprakstīta tīmekļa lietotnes veidošana, kas nodarbojas ar parakstu pievienošanu un parakstu pārbaudi PDF dokumentos. Tiek parādīts, …

Summary of Week VII

2018

International audience; Week VII of the INT program 2018 “Probing Nucleons and Nuclei in High Energy Collisions” was dedicated to topics at the interface of the electron-ion collider (EIC), heavy ion and proton-nucleus collisions. The EIC will provide complementary tools to investigate and constrain the initial state in HIC collisions, as well as transport properties of QCD matter which can be extracted from observables that are sensitive to final states interactions such as pt-broadening and energy loss. The contributed talks and discussions covered a variety of physics topics from saturation physics and the origin of multi-particle correlations in HIC to jet quenching and the strong coupl…

Spatially dependent parton distribution functions and hard processes in nuclear collisions

2014

First measurement of the Sivers asymmetry for gluons using SIDIS data

2017

The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. It was extracted from measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it turned out to be non-zero for quarks. In this letter the evaluation of the Sivers asymmetry for gluons in the same process is presented. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simul…