2,814 research outputs found
Hitchhiker's guide to the fractional Sobolev spaces
No full textThis paper deals with the fractional Sobolev spaces W-s,W-p. We analyze the relations among some of their possible definitions and their role in the trace theory. We prove continuous and compact embeddings, investigating the problem of the extension domains and other regularity results. Most of the results we present here are probably well known to the experts, but we believe that our proofs are original and we do not make use of any interpolation techniques nor pass through the theory of Besov spaces. We also present some counterexamples in non-Lipschitz domains. (c) 2011 Elsevier Masson SAS. All rights reserved
Regularity of Envelopes
No full textLet X be a compact complex manifold of complex dimension n and α be a smooth closed real form on X such that its cohomology class {α}∈H1,1(X,R) is big. In this paper we prove that, given a bounded function f with bounded distributional laplacian in X, the α-psh envelope P(f) is also locally bounded with locally bounded distributional laplacian on the ample locus of {α}
LHCspin: A polarized internal target for the LHC
No full textThe LHCspin project aims to bring both unpolarized and polarized physics at the LHC through the installation of a gaseous fixed target at the upstream end of the LHCb detector. The forward geometry of the LHCb spectrometer (2 < η < 5) is perfectly suited for the reconstruction of particles produced in fixed-target collisions. The fixed-target configuration, with center-of-mass energies ranging from √sNN = 72 GeV in collisions with Pb beams to √s = 115 GeV in pp interactions, allows to cover a wide backward center-of-mass rapidity region, corresponding to the poorly explored high x-Bjorken and high x-Feynman regimes. The use of transversely polarized H and D targets will allow to study the quarks TMDs in p-p collisions at unique kinematic conditions. Furthermore, being LHCb specifically designed for heavy-flavor physics, final states with c- or b-quarks (e.g. inclusive quarkonia production) will be efficiently reconstructed, thus providing, among other fundamental measurememnts, access to the so-far unknown gluons TMDs. The contribution focuses on the design considerations of the polarized internal target and on a discussion of possible critical machine issues
MEASUREMENT OF THE η′ GLUONIUM CONTENT AND OF THE MASS AT KLOE
No full textHere we update the measurement of the η′ gluonium content and present the final result of the η mass measurement. The η′ gluonium content is estimated by fitting the ratio Rφ = BR(φ → η′γ)/BR(φ → ηγ) together with other decay branching ratios. The analyses have been performed on 450 pb−1 of data collected in the years 2001 and 2002
The LHCspin project: A polarized target experiment at LHC
No full textA polarized target, operated in combination with the high-energy, high-intensity LHC beams and a highly performing LHC particle detector, has the potential to open new physics frontiers and to deepen our understanding of the intricacies of the strong interaction in the non-perturbative regime of QCD. Specifically, the LHCspin project aims to perform spin physics studies in high-energy polarized fixed-target collisions using the LHCb detector. Being designed and optimized for the detection of heavy hadrons, the LHCb spectrometer, in combination with the LHCspin setup, will provide a complementary access to the nucleon structure, e.g., by studying inclusive production of c- and b-hadrons, which represent an ideal tool to access the essentially unexplored spin-dependent gluon TMDs. Furthermore, fixedtarget collisions with 7 TeV proton beams, corresponding to center-of-mass energies ranging from 115 GeV in pp interactions to 72 GeV per nucleon in collisions with ion beams, will allow to cover a wide backward rapidity region, corresponding to the poorly explored high x-Bjorken and high x-Feynman regimes. The status of the LHCspin project is presented along with a selection of physics opportunities
Internal gas target experiments at the LHC
No full textThe physics opportunities offered by a fixed-target program using the proton and lead-ion beams of the LHC is wide and exciting. The LHC beams can provide the most energetic fixed-target measurements by pp, pA, and PbA collisions at √sNN = 72–115 GeV probing unexplored regions of the kinematical plane, including the high-x region. In the case of an unpolarized target the physics rich ranges from QCD to astroparticle, while the polarized target option opens the ground to novel measurements of TMDs, thereby contributing with a complementary approach to the understanding of the dynamics of the quark-gluon interplay inside the nucleon up to the 3-dimensional description of the nucleons. Among the main LHC experiments LHCb is the most suitable to host a fixed gas target. A description of the ongoing fixed-target proposals aimed at having the first LHC unpolarized data in Run3 and polarized data in Run4 will be discussed
Cavità di origine antropica e sicurezza degli edifici scolastici nella città di Roma: i casi di studio di via Asmara (Municipio II) e via Diana (Municipio V)
No full textNegli ultimi anni l'incremento di fenomeni di sprofondamento nel territorio di Roma
Capitale e nella sua area metropolitana costituisce un rischio sempre maggiore per la
popolazione e per le infrastrutture. Il verificarsi di questi eventi è in gran parte dei casi
connesso alla presenza di sistemi caveali di origine antropica e diversa età e funzione.
Il presente studio ha permesso di perfezionare un protocollo speditivo di utilizzo integrato di
alcuni metodi geofisici (microgravimetrico, georadar e sismico) funzionale
all’individuazione di cavità nel sottosuolo, che permette di mappare dimensioni,
distribuzione spaziale e profondità. Tale base informativa risulta imprescindibile per una
gestione in sicurezza degli edifici scolastici esistenti e per la progettazione di nuovi
interventi.Published1 dicembre 2017, Sala Convegni del CNR, P. le Aldo Moro, Roma7A. Geofisica per il monitoraggio ambientale7SR AMBIENTE – Servizi e ricerca per la societ
Towards hardware acceleration for parton densities estimation
No full textIn this proceedings we describe the computational challenges associated to the determination of parton distribution functions (PDFs). We compare the performance of the convolution of the parton distributions with matrix elements using different hardware instructions. We quantify and identify the most promising data-model configurations to increase PDF fitting performance in adapting the current code frameworks to hardware accelerators such as graphics processing units
The LHCSpin project
No full textThe LHCspin project aims to bring both unpolarized and polarized physics at the LHC through the installation of a gaseous fixed target at the upstream end of the LHCb detector. The forward geometry of the LHCb spectrometer (2 < η < 5) is perfectly suited for the reconstruction of particles produced in fixed-target collisions. The fixed-target configuration, with center-of-mass energies ranging from √sNN = 72 GeV in collisions with Pb beams to √s = 115 GeV in pp interactions, allows to cover a wide backward center-of-mass rapidity region, corresponding to the poorly explored high x-Bjorken and high x-Feynman regimes. The project has several ambitious goals regarding heavy-ion physics and new-era quantitative searches in QCD through the study of the nucleon's internal dynamics in terms of both quarks and gluons degrees of freedom. In particular, the use of transversely polarized H and D targets will allow to study the quarks TMDs in pp collisions at unique kinematic conditions. Furthermore, being LHCb specifically designed for heavy-flavor physics, final states with c- or b-quarks (e.g. inclusive quarkonia production) will be efficiently reconstructed, thus providing, among other fundamental measurememnts, access to the so-far unknown gluons TMDs. The status of the project is presented along with a selection of physics opportunities
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