4,753 research outputs found
Preliminary measurements of the quark-antiquark production cross- section in annihilations up to LEP2 highest energies
No full textData collected with the DELPHI detector at square root s up to LEP2 highest energies (i.e. exceeding 205 GeV) have been used to extract preliminary values of the cross-sections for quark-antiquark pair- production in e/sup +/e/sup -/ annihilations. The values found were used to test the Standard Model predictions and to seek for physics beyond it. (6 refs)
Semileptonic branching ratios and moments
No full textRecent B physics results from the BaBar, Belle, CLEO, and LEP collaborations are reviewed. In particular, results on semileptonic B meson branching ratios and spectral moments are presented
Fermion pair cross-sections and asymmetries and limits on new physics
No full textThe measurements of hadron and lepton pair production cross-sections and lepton pair forward-backward asymmetries performed by the ALEPH, DELPHI, L3 and OPAL collaborations are summarized. The results obtained with data taken at centre-of-mass energies between 130 and 207 GeV, including the events recorded in the early summer 2000 at 205 and 207 GeV, show no significant deviations from the standard model predictions. This allows to constrain new physics phenomena like contact interactions, additional heavy gauge bosons Z', models of gravity in extra dimensions, exchange of sneutrinos or squarks in R- parity violating models and leptoquarks
Caratterizzazione meccanica e microstrutturale di acciai sinterizzati realizzati con polveri prive di nichel. (Mechanical and microstructural characterization of Ni-free powder steel.)
No full textAttualmente la maggioranza dei componenti meccanici in acciaio, realizzati con processo di sinterizzazione, utilizzano polveri contenenti anche nichel carbonile. Questa fine polvere di Nichel permette di ottenere pezzi con buoni valori di densità, tenacità e resistenza a fatica, ma al contempo è un elemento cancerogeno e dai costi elevati, la cui produzione è concentrata in un numero ristretto di stati extra EU.
Per tale ragione negli ultimi anni i produttori di polveri stanno sviluppando nuove formulazioni sostenibili e “green” non contenenti Ni. Una delle barriere alla diffusione di queste polveri risiede, però, nella mancanza sia di dati esaustivi riguardanti il comportamento meccanico del materiale realizzato con queste polveri, sia di esempi di applicazioni di successo nella produzione di componenti ad alte prestazioni.
Allo scopo di favorire la diffusione dell’utilizzo delle polveri senza nichel, la EIT Raw Materials ha finanziato il progetto NEWMAN (Nickel frEe poWders for high perforMAnce compoNents), mirante ad identificare quali di queste polveri siano al contempo adatte per la realizzazione di componenti meccanici alto prestazionali e utilizzabili per la produzione industriale di componenti per il settore automotive e per sistemi di misura di precisione.
All’interno del progetto è stata eseguita una preliminare caratterizzazione di 3 diverse polveri: Astaloy 85Mo+0,25C, Astaloy CrA+0,25C e Astaloy CrA+0,6C. Su queste sono state eseguite analisi di densità e microstrutturali e prove meccaniche. I risultati ottenuti hanno evidenziato come le polveri senza nichel, se affiancate da un’appropriata ottimizzazione di processo, trattamento termico e progettazione, possano sostituire le tradizionali polveri con nichel nella produzione di manicotti scorrevoli per cambi automobilistici e componenti di precisione utilizzati in macchine di misura
Autoencoder-based Anomaly Detection System for Online Data Quality Monitoring of the CMS Electromagnetic Calorimeter
No full textThe CMS detector is a general-purpose apparatus that detects high-energy collisions produced at the LHC. Online data quality monitoring of the CMS electromagnetic calorimeter is a vital operational tool that allows detector experts to quickly identify, localize, and diagnose a broad range of detector issues that could affect the quality of physics data. A real-time autoencoder-based anomaly detection system using semi-supervised machine learning is presented enabling the detection of anomalies in the CMS electromagnetic calorimeter data. A novel method is introduced which maximizes the anomaly detection performance by exploiting the time-dependent evolution of anomalies as well as spatial variations in the detector response. The autoencoder-based system is able to efficiently detect anomalies, while maintaining a very low false discovery rate. The performance of the system is validated with anomalies found in 2018 and 2022 LHC collision data. In addition, the first results from deploying the autoencoder-based system in the CMS online data quality monitoring workflow during the beginning of Run 3 of the LHC are presented, showing its ability to detect issues missed by the existing system
Performance of the front-end electronics of the CMS electromagnetic calorimeter barrel for the High-Luminosity LHC
No full textNickel-free steel powders: Paving the way for sustainable Powder Metallurgy
No full textFew sectors of industry remain untouched by the demands of sustainability. The response to climate change has ramped up considerably in most countries, with consumers and regulators alike looking for greater assurance that products have the lowest environmental impact possible across the value chain. PM is no exception, and increasing numbers of PM projects on sustainability have emerged to meet this need. The EU’s NEWMAN project is one such effort, seeking to drastically improve PM’s economic and environmental sustainability by minimising nickel content in steel powders. Here, the NEWMAN partners discuss the project’s goals, progress and roadmap to completion
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