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Regression Deep Neural Networks for top-quark-pair resonance searches in the dilepton channel
No full textSeveral Beyond Standard Model (BSM) theories predict the existence of new massive particles decaying to pairs of top quarks, tt¯. In this concept work, the key observable for such resonance searches, the top-pair system invariant
mass, mtt¯, is reconstructed by training a deep neural network on a sample of simulated tt¯ events. A regression task is then performed on both tt¯ and Z signal events,
using mtt¯ as output parameter. The comparison between this machine learning approach and more traditional system reconstruction techniques highlights a tangible improvement in the ability to correctly reconstruct and resolve a TeV-scale tt¯ resonance peak
Search for the Higgs boson decaying to a pair of charm quarks at a future Multi-TeV Muon Collider
No full textThis paper presents a feasibility study aiming to estimate the precision achievable on the Higgs-to-charm-quark coupling at a future Muon Collider. The accurate measurement of the Yukawa couplings is of invaluable importance in High Energy Particle Physics, as it sheds light on the Electroweak Symmetry Breaking mechanism. In particular, the couplings to the second generations of fermions are of extreme interest due to sensitivity to a whole class of new physics models, but their measurement is extremely challenging, because of the small branching ratio. The coupling to charm quark, especially, is currently not accessible at LHC but could be probed at future lepton colliders. Within this work, the search for H → cc¯ at Muon Collider has been performed. The μ+μ− → Hνν¯ → ccν¯ ν¯ signal process has been fully simulated and reconstructed at √s = 1.5 TeV, along with the main physics backgrounds. The machine background originating from the decay of muons in the beam, the so-called Beam Induced Background, is not included in this preliminary study. With the aim of improving the rejection of jets coming from b-quark and u-d-s-g hadronization, a charm quark tagging algorithm has been developed by employing Machine Learning techniques. Finally, the relative uncertainty on the coupling at √s = 1.5 TeV is estimated to be 5.5%. A projection to √s = 3 TeV shows that precision improves with increasing energy, reaching the value of 2.6%
Feasibility study on the search for H → ZZ∗ → 4μ at a muon collider
No full textAmong the hadron and lepton colliders proposed for the future of HEP, a multi-TeV muon collider currently represents the best candidate to probe the Higgs boson properties and, possibly, search for new physics. In this paper, a feasibility study on the search for H → ZZ∗ → 4μ at a muon collider is briefly exposed. Signal and Standard Model (SM) irreducible background processes are studied in two center-of-mass energy scenarios, 1.5 and 3 TeV, in order to present a first estimate of the sensitivity of the Higgs boson coupling to Z bosons achievable at this facility. The impact of the machine background (BIB), due to the decay of beam muons, is evaluated in the 1.5 TeV scenario. This work also provides an evaluation of the muon system reconstruction performance
Quantum spin Hall based heterostructures
No full textA summary of my presentation at the Congresso Nazionale SIF
2021 is given. The potential of quantum spin Hall based heterostructures is briefly reviewed with particular emphasis on the role of the possible gap opening mechanisms: magnetic barriers, superconducting barriers, strong interactions, constriction potentials
Measurements of the 16O cross section on a C target with the FOOT apparatus
No full textIn particle therapy (PT) nuclear interactions of the beam with the body cause fragmentation of both the projectile and target nuclei. Fragmentation processes need to be taken into account when planning a PT treatment, but the evaluation of their impact is limited because of the lack of experimental data. The FOOT (FragmentatiOn Of Target) collaboration designed an experiment aiming to the measurement of the differential cross sections of interest in PT. In this paper, an overview of the FOOT experiment, the experimental setup and the measurement strategy will be discussed. In addition, preliminary results of a 400 MeV/u 16O beam impinging on a C target will be presented
Low-power programmable integrated photonic circuits fabricated by femtosecond laser micromachining
No full textPhotonic integrated circuits (PICs) are steadily becoming an established technology with a wide range of applications in communications, sensing and analog signal processing. PICs manipulate light signals using waveguides, directional couplers and phase shifters as building blocks. Recently, there has been growing interest in fully reconfigurable PICs, which can be programmed to perform any linear transformation on the input signal. Femtosecond Laser Micromachining (FLM) is a versatile fabrication technology that allows rapid and cost-effective fabrication of PICs. Reconfigurability in FLM PICs is implemente by means of thermal phase shifters, which provide optical signal modulation without added signal loss. Until recently only few thermal shifters could be fabricated on the same chip due to their high power dissipation and thermal crosstalk. This limitation can be overcome with the introduction of isolation structures fabricated via FLM, which provide a
more than ten-fold reduction in dissipated power and crosstalk, allowing us to fabricate fully programmable PICs with tens of thermal shifters integrated into the same
device
Design and validation of an instrument to measure participation of students in the activities of the National Plan for Scientific Degrees (PLS): The SAAE instrument
No full textIn this study, we present a questionnaire aimed at evaluating the involvement of students in the activities of the National Plan for Scientific Degrees (Piano Lauree Scientifiche) through the multidimensional construct of engagement. The questionnaire was presented to about 1000 secondary school students attending Biology, Chemistry and Physics PLS activities at the Federico II University of Naples. The instrument has four dimensions: Satisfaction with the activities followed, Utility of the PLS, Difficulties in following the activities, Involvement of
close people. Students were then clustered according to their answers to the questionnaire. Implications of the study for the evaluation of the third mission of the
universities are briefly presented
Machine Learning approach for the search of heavy diboson resonances in semi-leptonic final state at √s = 13 TeV with the ATLAS detector
No full textA Recurrent Neural Network-based approach has been adopted for the classification of the production mechanisms in the search of heavy resonances decaying in two bosons. The search is performed using proton-proton collision data
recorded with the ATLAS detector from 2015 to 2018. The investigated final state is semi-leptonic, where one boson decays in two leptons and the other decays hadronically. No excesses have been found in data with respect to the background-only hypothesis. Upper bounds on the production cross sections of heavy scalar, vector or tensor resonances are derived in the mass range 300–5000 GeV
Report finale Progetto Centro Internazionale di Studi Avanzati su Ambiente
Get PDFIl progetto “Centro Internazionale di Studi Avanzati su Ambiente, ecosistema e Salute umana” –
CISAS – ha offerto uno schema organizzativo complesso e concreto idoneo ad indagare con una
moderna visione multidisciplinare l'inquinamento ambientale e il suo legame con l'ecosistema e la
salute umana. Il principale obiettivo del programma di ricerca effettuato è stato comprendere i
processi ed i meccanismi per il trasferimento di contaminanti convenzionali (metalli pesanti, POP,
radionuclidi, ecc.) ed emergenti (es. PBDE, antibiotici, farmaci di nuova generazione, antitumorali,
ecc.) dall'ambiente (come complesso di atmosfera, suolo, sedimenti, acque interne e matrici
marine) all'ecosistema e all'uomo
Metodi di campionamento e conservazione dell’ittioplancton
Get PDFLo studio delle popolazioni ittioplanctoniche è ormai riconosciuto su scala internazionale, quale
indice di rilevanza fondamentale per l’analisi della biodiversità e per la qualità degli ecosistemi marini.
Tale studio è fondamentale per comprendere le dinamiche delle popolazioni ittiche. La conoscenza
della distribuzione e dell'abbondanza di uova e larve, ottenute attraverso campionamenti del
plancton, può aiutare a migliorare la comprensione della distribuzione spaziale delle risorse alieutiche
e dei processi che incidono sulle fluttuazioni degli stock, ponendo le basi per una migliore gestione
di queste risorse. È dunque di fondamentale importanza riconoscere, classificare e analizzare in
dettaglio l’ittioplancton, per identificare le aree di riproduzione delle specie ittiche al fine di tutelarle
e preservarle. Numerose riserve naturali infatti fondano la loro esistenza proprio nelle zone di
spawning o di nursery dove appunto le specie si riproducono e dove le larve e i giovanili trovano le
condizioni ideali per accrescersi fino al momento della metamorfosi. Conoscere e preservare è quindi
un processo fondamentale, specialmente in aree interessate da fenomeni come l’inquinamento o
dove lo sforzo di pesca rischia di compromettere lo stato di salute delle comunità ittiche. Questo
rapporto tecnico vuole offrire un contributo metodologico alla fase di raccolta e conservazione delle
uova e larve dei pesci, che successivamente verranno identificate e adoperate per le diverse analisi a
cui andranno incontro