1,688 research outputs found
Charm suppression in Pb-Pb collisions at the LHC measured using D0 K-Ï + reconstruction with the ALICE experiment
No full textThe thesis is focused on the measurement of the nuclear modification of charm quark production, in lead-lead collisions at the Large Hadron Collider. This observable is sensitive to the interaction of this quark with the high-density strongly interacting medium formed in ultra-relativistic heavy-ion collisions and, thus, to the properties of the state of matter. The partons traversing the medium lose energy via gluon radiation or elastic collisions with other partons already present in the medium. The charm quark allows to study the mass and colour charge dependences of the energy loss, since heavy quarks are expected to behave differently from light partons.
The measurement presented in this thesis is performed for the first time in nucleus-nucleus collisions, with the full reconstruction of D mesons via their hadronic decay. The strategy to reconstruct D0 mesons in the two-prong decay D0->K-ÃÂÃÂ+, with the ALICE experiment, will be described. Results obtained in Pb-Pb collisions at the energy of 2.76 TeV in the centre of mass of the collision for nucleons pair will be shown. In particular, the selection cut optimization was studied to compute the raw signal of D mesons with an invariant mass analysis. Selection and reconstruction efficiencies were considered with the detector acceptance, to correct for experimental effects. The corresponding data systematic uncertainties were evaluated in detail.
The comparison with the production cross section obtained in proton-proton collisions at the same energy allows then to compute the nuclear modification of D0 meson, the first direct evidence of the charm quark energy loss.
The measurement was compared with other open heavy flavour results and with light-charged hadrons suppression, measured at the LHC, to test the mass and colour charge dependences of the interaction with the medium. Results have been also compared with models that compute the charm quark energy loss using different theoretical approaches.
These results were recently approved by the ALICE Collaboration and a publication has been proposed and is being review by the Collaboration.La tesi descrive la misura della modifica della produzione di quark charm, in collisioni tra ioni piombo al Large Hadron Collider. Questa misura permette di studiare l'interazione del quark charm con il mezzo ad alta densitÃÂàe fortemente interagente, formato in collisioni di ioni pesanti ad energie ultra-relativistiche e le proprietÃÂàdi questo stato della materia. I partoni che attraversano il mezzo perdono energia per emissione di gluoni (gluonnstrahlung) e collisioni elastiche con gli altri partoni del mezzo. Il quark charm permette di studiare come variano le proprietÃÂàdell'interazione in funzione della massa e della carica di colore del quark, poichÃÂé i modelli teorici prevedono un comportamento diverso dei quark pesanti nel mezzo, rispetto a quelli leggeri.
La misura presentata in questa tesi ÃÂÃÂ ̈ la prima fatta in collisioni tra nuclei pesanti, attraverso la ricostruzione esclusiva dei mesoni D nel loro decadimento adronico. In particolare, verrÃÂÃÂ presentata la strategia di ricostruzione del mesone D0 nel suo decadimento in due corpi D0->K-ÃÂÃÂ+, fatta con l'esperimento ALICE. Verranno, quindi, illustrati i risultati ottenuti con i dati di collisioni Pb-Pb ad un energia nel centro di massa per coppia di nucleoni di 2.76 TeV. In particolare, ÃÂÃÂ ̈ stata studiata l'ottimizzazione dei tagli di selezione per misurare il segnale, estratto con un'analisi di massa invariante. Le efficienze di selezione e ricostruzione delle particelle e gli effetti di accettanza del rivelatore, sono stati considerati con uno studio Monte Carlo, per considerare gli effetti sperimentali. Nella tesi viene anche descritto in dettaglio lo studio sulle incertezze sistematiche.
Il confronto delle sezioni d'urto di produzione ottenute in collisioni Pb-Pb e protone-protone, alla stessa energia, permette di misurare il fattore di modifica nucleare del mesone D0, prima evidenza diretta di perdita energia del quark charm nel mezzo.
La misura ÃÂÃÂ ̈ stata confrontata con altri risultati ottenuti nel settore dei quark pesanti alla stessa energia, e con la soppressione degli adroni carichi, per valutare le dipendenze dalla massa e dalla carica di colore del quark, nella sua interazione con il mezzo. I risultati sono stati confrontati con modelli teorici che descrivono la perdita di energia del quark charm, utilizzando diversi metodi di calcolo.
I risultati sono stati recentemente approvati dalla collaborazione ALICE, una pubblicazione ÃÂÃÂ ̈ stata proposta ed ÃÂÃÂ ̈ in fase di review nella collaborazione
Correction to: When terminology hinders research: the colloquialisms of transitions of control in automated driving (Cognition, Technology & Work, (2022), 10.1007/s10111-022-00705-3)
No full textIn the original article, author affiliation published with error. The correct affiliations are: Davide Maggi—Institute for Transport Studies, Leeds, UK. Richard Romano—Institute for Transport Studies, Leeds, UK. Oliver Carsten—Institute for Transport Studies, Leeds, UK. Joost C. F. De Winter—Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands. The original article has been corrected.Human-Robot Interactio
Admiel Kosman, Siamo giunti a Dio
No full textInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Admiel Kosman, Siamo giunti a Dio
No full textInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Starchitecture: Scenes, Actors and Spectacles in Contemporary Cities
No full textHow and why do spectacular buildings get commissioned and procured? What are their visible urban effects? What can urban planners, architects, and policymakers learn in order to engage in more successful citymaking?
In recent years, media and critical attention has been lavished on famous architects, and the contributions of their designs to the branding of cities. The post-“Bilbao effect” global landscape is one where cities compete for the highest-profile skyscrapers, cultural projects, and high-profile developments designed by star architects whom even casual readers know by first name: Frank Gehry, Bjarke Ingels, Jean Nouvel, Zaha Hadid, Norman Foster, Rem Koolhaas. Far less is known about the decision-making processes behind these projects and their subsequent urban effects.
A unique combination of urban studies and photography, Starchitecture investigates projects designed by star architects in cities including Paris, New York, Abu Dhabi, Bilbao, and the architectural microcosm of the Vitra campus in Weil am Rhein, Germany. Author Davide Ponzini and photographer Michele Nastasi seek to explain and critique a growing global condition by revealing how starchitecture has been and continues to be deployed in cities around the world. The arguments they raise are vital to understanding the urban landscapes of today, and tomorrow
Design and characterization of a fractal-inspired multi-frequency piezoelectric energy converter
No full textA promising harvesting technique, in terms of simplicity and efficiency, is the conversion of ambient kinetic energy through piezoelectric materials. This work aims to design and investigate a piezoelectric converter conform to a fractal-inspired, multi-frequency structure previously presented by the author. A physical prototype of the converter is built and experimentally examined, up to 120 Hz, in terms of modal response and power output. Three eigenfrequencies are registered and the power output is particularly good at the fundamental eigenfrequency. Also the effect of the resistive load applied to the converter is investigated
Checking Flavour Models at Neutrino Facilities
No full textAbstractIn the recent years, the industry of model building has been the subject of the intense activity, especially after the measurement of a relatively large values of the reactor angle. Special attention has been devoted to the use of non-abelian discrete symmetries, thanks to their ability of reproducing some of the relevant features of the neutrino mixing matrix. In this Letter, we consider two special relations between the leptonic mixing angles, arising from models based on S4 and A4, and study whether, and to which extent, they can be distinguished at superbeam facilities, namely T2K, NOνA and T2HK
Measurement of heavy-favour production in pp and Pb-Pb collisions at the LHC with ALICE
No full textLatest results on open heavy favour measurements in pp collisions at 7 TeV and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV with the ALICE experiment are presented. The results of the single lepton analyses (electrons at central rapidity, muons at forward rapidity) and D meson reconstruction will be discussed.Latest results on open heavy favour measurements in pp collisions at 7 TeV and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV with the ALICE experiment are presented. The results of the single lepton analyses (electrons at central rapidity, muons at forward rapidity) and D meson reconstruction will be discussed
La rilevanza del rischio economico nella definizione dell’ambito soggettivo di applicazione della disciplina sui contratti pubblici e del diritto della concorrenza
No full textL’articolo si propone di analizzare il ruolo del rischio economico come criterio
idoneo a delineare l’ambito soggettivo di applicazione del diritto europeo dei
contratti pubblici e del regime della concorrenza. L’analisi si incentra sull’in-
terpretazione delle nozioni di “organismo di diritto pubblico” e di “impresa”. Il
contributo intende evidenziare la crescente importanza dell’analisi economica
come criterio ermeneutico utile a segnare il confine tra “pubblico” e “privato”,
tra “attività amministrativa” e “attività d’impresa”.The essay examines the role of economic risk in identifying the scope of public
procurement and competition law. The widespread use of private law institutions
by the public sector creates uncertainty about whether to apply public procurement
or competition law or both. According to the author, the concept of economic risk
could represent a decisive criterion for marking the boundaries between the two
areas of law. Consistently, the author highlights the importance of a “more
economic approach” in the application of European internal market law
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