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Статті в журналах з теми "SCUOLA DI DOTTORATO DI RICERCA IN FISICA"
Marcon, Alessandra, and Elvira Pietrobon. "Deconstructing paradigms of Western thought." CRIOS, no. 23 (October 2022): 78–87. http://dx.doi.org/10.3280/crios2022-023008.
Повний текст джерелаCerbara, Loredana, and Maria Girolama Caruso. "Fragilità e rischio di povertà educativa negli adolescenti in Italia. I dati delle indagini del CNR-IRPPS." WELFARE E ERGONOMIA, no. 1 (June 2020): 119–27. http://dx.doi.org/10.3280/we2020-001011.
Повний текст джерелаDIAS, Gabrielle Batista, Nilza Fátima Virgem FERREIRA, and Ronan Daré TOCAFUNDO. "A contribuição da Logosofia para a docência na Educação Física." INTERRITÓRIOS 5, no. 9 (December 9, 2019): 330. http://dx.doi.org/10.33052/inter.v5i9.243601.
Повний текст джерелаSCHINDHELM, Virginia Georg. "Gênero, sexualidades e os desafios para educadore(a)s infantis." INTERRITÓRIOS 6, no. 10 (April 14, 2020): 73. http://dx.doi.org/10.33052/inter.v6i10.244894.
Повний текст джерелаCalleja-Reina, Marina, José Manuel Rueda Gómez, and Antonio Barbosa Gonzalez. "Relación entre la práctica deportiva en Clubes Deportivos y la mejora del control de la impulsividad en escolares." Cuadernos de Psicología del Deporte 21, no. 1 (January 1, 2021): 179–91. http://dx.doi.org/10.6018/cpd.437791.
Повний текст джерелаRibeiro, Edivan Charlton do Nascimento, Amanda Alves Fecury, Euzébio de Oliveira, Carla Viana Dendasck, and Claudio Alberto Gellis de Mattos Dias. "Abilità elevate nell'EPT e nell'insegnamento regolare: una rassegna degli ultimi cinque anni." Revista Científica Multidisciplinar Núcleo do Conhecimento, January 18, 2022, 111–30. http://dx.doi.org/10.32749/nucleodoconhecimento.com.br/formazione-it/abilita-elevate-nellept.
Повний текст джерелаДисертації з теми "SCUOLA DI DOTTORATO DI RICERCA IN FISICA"
Pakdast, Seid Hossein. "Advanced MEMS resonator for mass detection and micromechanical transistor." Doctoral thesis, Università degli studi di Trieste, 2012. http://hdl.handle.net/10077/6690.
Повний текст джерелаCantilever sensors have been the subject of growing attention in the last decades and their use as mass detectors proved with attogram sensitivity. The rush towards the detection of mass of few molecules pushed the development of more sensitive devices, which have been pursued mainly through downscaling of the cantilever-based devices. In the field of mass sensing, the performance of microcantilever sensors could be increased by using an array of mechanically coupled micro cantilevers of identical size. In this thesis, we propose three mechanically coupled identical cantilevers, having three localized frequency modes with well-defined symmetry. We measure the oscillation amplitudes of all three cantilevers. We use finite element analysis to investigate the coupling effect on the performance of the system, in particular its mass response. We fabricated prototype micron-sized devices, showing that the mass sensitivity of a triple coupled cantilever (TCC) system is comparable to that of a single resonator. Coupled cantilevers offer several advantages over single cantilevers, including less stringent vacuum requirements for operation, mass localization, insensitivity to surface stress and to distributed a-specific adsorption. We measure the known masses of silica beads of 1µm and 4µm in diameter using TCC. As it is difficult to obtain one single bead at the free end of the cantilevers, we choose to use the Focused Ion Beam. By sequential removing mass from one cantilever in precise sequence, we proved that TCC is also unaffected from a-specific adsorption as is, on the contrary, the case of single resonator. Finally, we proposed shown the use of TCC can be as micromechanical transistor device. We implemented an actuation strategy based on dielectric gradient force which enabled a separate actuation and control of oscillation amplitude, thus realizing a gating effect suitable to be applied for logic operation.
XXIV Ciclo
1980
Fan, Xi Long. "Galaxy evolution by chemical and SED model." Doctoral thesis, Università degli studi di Trieste, 2012. http://hdl.handle.net/10077/7429.
Повний текст джерелаIn this thesis, we have studied the ISM, QSO, LGRB hosts and LBGs by galactic chemical evolution and spectro-photometric models. We also tested the so-called mono- lithic scenario of elliptical galaxies formation. Here we present the main results of this work: 1. The star formation history is the main driver of galaxy evolution. The predictions of elliptical chemical evolution models with the so-called monolithic scenario of elliptical galaxies formation are consistent with the data of high redshift LBGs and QSOs. Both the infall and the star formation timescale are suggested to decrease with galactic mass. This scenario is confirmed by the spectro-photometric models by reproducing the average SED of MIPS-LBGs. This so-called “ downsizing” of SFH is consistent with many observations. 2. Our M = 1012M⊙ elliptical model can reproduce super-massive BH mass, stellar mass, gas mass and dust mass of one of the most distant QSO ever observed J1148+5251 (z ≃ 6.4). The same model can also reproduce [N/C] versus [C/H] and [Si/C] versus [C/H] of the NLRs in QSO hosts. The very high C abundance observed in these QSOs can be explained only by assuming yields with mass loss from massive stars with a strong dependence on metallicity, as those of Maeder (1992) 3. Our elliptical models suggested the LBGs at hight redshift are likely to be young (age < 0.6 Gyr) ellipticals. This picture is consist with the results of spectro- photometric models. By chemical evolution models, we found that, LBGs in A- MAZE and LSD samples, CB 58, Clone and Cosmic Horseshoe are of intermediate mass(1010 − 3 · 1010M⊙). Our elliptical model for 3 · 1010M⊙ well reproduces the [O/H] abundance as a function of redshift for these LBGs. By spectro-photometric models, we found that theMIPS-LBGs are more massive (∼ 1011M⊙). Our spectro- photometric models for 1011M⊙ well reproduce the average SED of MIPS-LBGs. 4. Our elliptical models suggested that if the observed high-redshift LGRB-DLAs and local LGRB host galaxies belonged to an evolutionary sequence, they should be irregulars with a common galaxy-formation redshift as high as zf = 10, observed at different phases of their evolution. We cannot exclude, however, that they correspond to the outermost regions of spiral disks, since their properties are similar to those of irregulars. Elliptical galaxies cannot be LGRB host galaxies at low 111 redshift and that they are very unlikely hosts of LGRB-DLAs even at high redshift, because of their rapid chemical enrichment at high redshift following the occurrence of a galactic wind several Gyrs ago and subsequent passive evolution. 5. Our elliptical models suggested that a dust mass-stellar mass relation exists, with more massive galaxies attaining a higher dust content at earlier time. The dust evolution in ISM make the main contribution for the large amount of dust in high redshift QSOs. QSO itself produced dust but this production appears negligible compared to that from stellar sources, unless one focuses on the very central regions at times very close to the galactic wind onset. 6. The dust mass estimation in the average MIPS-LBGs based on the combination of our elliptical models and spectro-photometric models is not consistent with the one based on simple temperature grey-body fitting. The Milky Way dust parameters can not reproduce the average SED of MIPS-LBGs with the SFHs from chemical evolution models. The more dense dusty environments and flatter dust size distributions are needed to reproduce the average SED of MIPS-LBGs with these SFHs. 7. IGIMF of starburst galaxies can improve the [α/Fe] ratios, however it still can- not solve the discrepancy between predictions and data. Dust effect is the most plausible solution.
XXIV Ciclo
1981
Formato, Valerio. "Measurement of the nuclear and isotopic composition of galactic cosmic rays with the PAMELA experiment." Doctoral thesis, Università degli studi di Trieste, 2014. http://hdl.handle.net/10077/9962.
Повний текст джерелаThis thesis describes the study of the isotopes of hydrogen and helium and of the boron and carbon nuclei in the cosmic radiation. New measurements of the fluxes of 1H, 2H, 3He, 4He, between 120 MeV/n and 900 MeV/n, and of the boron and carbon fluxes, between 400 MeV/n and 120 GeV/n, are presented at the top of the atmosphere. The measurements were made with the space-borne PAMELA experiment from July 2006 to March 2008, that is during a period of minimum solar activity and negative solar magnetic field polarity. Such measurements can help in achieving a more detailed knowledge of the physics of cosmic ray propagation inside the Galaxy, which is a key ingredient in interpreting cosmic ray origin, acceleration mechanism and the possible presence of new physics.
XXVI Ciclo
1986
Candelise, Vieri. "Measurement of the associated productionof a Z boson and b quarksin proton-proton collisions at √s = 8 TeVwith the CMS experiment at LHC." Doctoral thesis, Università degli studi di Trieste, 2014. http://hdl.handle.net/10077/9960.
Повний текст джерелаThe aim of the thesis work is the measurement of the associated production of a Z boson and b quarks with the 2012 collision data recorded by the CMS experiment at 8 TeV in proton-proton collisions at LHC. The importance of this physics process comes from the understanding of the perturbative Quantum Chromodynamics calculation schemes of the b quark content inside the proton and how this quark is extracted in the collision. Thus, the Z+b physics can be used for many relevant Standard Model measurements, such as the Z+b polarization asymmetry and the Higgs boson to b quarks background description. Nevertheless, many New Physics scenarios predict new particles decaying into Z+b or have enhanced Z+b cross sections, and for these reasons this process is considered as one of the most promising Standard Model final states to be used in searches at LHC. I have focused my attention on the development of the code needed to perform the analysis for the Z+b observables measured with the CMS data. First, I have built up the analysis framework for the selection of a Z boson decaying into muons and electrons, the jets characterization, and the implementation and study on the b-jets tagging. Then I have studied the various backgrounds and developed a strategy to extract the relative b-quark, c-quark and light flavour components from the Monte Carlo simulation by fitting the relative templates. A specific study on the estimation of the contamination of top quark pairs in the analysis has been done employing a data driven technique with an electron plus muon pairs final state with enhanced missing energy. In order to compare the results obtained in data with the different theoretical predictions of the b quark production in proton collisions, many unfolding techniques have been tested, and checks on the applied methods have been done using several Monte Carlo predictions. Finally, the evaluation of all the systematic sources of error has been quoted and added in the presentation of the final results. The differential cross sections of pp to Z+b process have been measured as a function of the leading b-jet momentum and pseudorapidity, the Z boson momentum, the angular difference between the Z boson and the leading b-jet, and the sum of all the jet momenta in the event. Then, the cross section ratio between the Z+b and the Z+jets processes has been calculated as a function of the observables mentioned above. All the results have been compared with the available theoretical calculations in perturbative Quantum Chromodynamics.
XXVI Ciclo
1987
Totaro, Pierluigi. "Search for a standard model Higgs boson in the tau-tau decay channel produced in proton-antiproton collisions at the center of mass energy of 1.96 TeV at Tevatron." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4487.
Повний текст джерелаIn questa tesi viene descritta la ricerca del bosone di Higgs del Modello Standard nel canale di decadimento in coppie di leptoni τ , condotta al Tevatron in collisioni protonantiprotone ad un’energia nel centro di massa √s = 1.96 TeV. L’analisi si basa su circa 2.3 fb−1 di dati raccolti dall’esperimento Collider Detector at Fermilab (CDF) ed e' stata effettuata considerando i seguenti processi di produzione di segnale: WH(→ τ τ ), ZH(→ τ τ ), qHq’→qτ τq’ e gg→H→ τ τ . Gli eventi sono selezionati richiedendo un τ adronico ed un elettrone (o muone) isolato, quest’ultimo proveniente dal decadimento leptonico di uno dei due τ originari. In aggiunta, almeno un getto calorimetrico deve essere presente nello stato finale. Il numero di eventi di fondo attesi e' 921.8±48.9 nel canale con un unico getto e 159.4±11.6 nel canale con due o piu' getti calorimetrici, mentre gli eventi osservati sono rispettivamente 965 e 166. Per aumentare la sensitivita' dell’analisi si e' impiegato di un metodo multivariato, basato su un set di Boosted Decision Trees allenati per separare il segnale dalle principali sorgenti di fondo. I dati non mostrano alcuna evidenza di produzione di bosoni di Higgs, pertanto sono stati calcolati i limiti al 95% di Livello di Confidenza sulla sezione d’urto di produzione, relativamente ai valori previsti dal Modello Standard. I risultati sono presentati per diversi possibili della massa del bosone di Higgs, nell’intervallo compreso tra 100 GeV/c^2 e 150 GeV/c^2. Nell’ipotesi MH = 120 GeV/c^2 il limite osservato e' 27.2 volte superiore alla sezione d’urto predetta, mentre il corrispondente valore atteso e' 23.4+9.8 −6.4.
This thesis describes the search for the Standard Model Higgs boson decaying to tau lepton pairs, in the Tevatron proton-antiproton collisions at a center of mass energy √s = 1.96 TeV. The search is based on approximately 2.3 fb−1 of CDF Run II data and is performed by considering the following signal processes: WH(→ τ τ ), ZH(→ τ τ ), qHq’→qτ τq’ and gg→H→ τ τ . Events are selected by requiring an hadronic tau and one isolated electron or muon, coming from the leptonic decay of one of the two taus. In addition, at least one calorimeter jet must be present in the final state. We expect 921.8±48.9 background events in the 1 jet channel and 159.4±11.6 in the ≥ 2 jets channel, while in data we observe 965 and 166 events, respectively. In order to improve the search sensitivity we employ a multivariate technique, based on a set of Boosted Decision Trees trained to get the best separation between signal and the dominant sources of background. We observe no evidence for a Higgs boson signal and therefore we set a 95% confidence level (C.L.) upper limit on the cross section relative to the SM predictions (σ/σSM). Results are presented for the Higgs boson mass varying from MH = 100 GeV/c^2 to MH = 150 GeV/c^2. For the mass hypothesis of 120 GeV/c^2 the observed limit is 27.2, while the corresponding expected value is 23.4+9.8−6.4.
XXII Ciclo
1982
Panizzo, Giancarlo. "Testing new physics with bottom quarks at LHC: a pragmatic approach." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10891.
Повний текст джерелаThis work discusses how Bottom-quark physics at the Large Hadron Collider (LHC) can be used as a probe to hint to Beyond the Standard Model Physics from a phenomenological point of view. In this contest, the calculation of three observables is presented, all related to the production of one boson (Z, or a Higgs particle of Beyond the Standard Model nature) in association with a bottom-quark. The Polarization Asymmetry of the Z-boson produced in association with a b-quark is computed at Leading Order, using the 5-flavours number scheme, assuming it is measured at the LHC with a center of mass energy of 14 TeV. It is shown how this observable can be used for an accurate determination of the A_b parameter, measured at the Stanford Linear Collider (and, indirectly, at the Large Electron Positron), and known to be in tension with its Standard Model prediction: this strongly motivates its new, independent, determination at the LHC. As an estimate of the theoretical uncertainties affecting the prediction of the Polarization Asymmetry, this is re-computed varying both the renormalization/factorization scale and the Parton Density Function set, showing its strong stability against such effects. The Forward-Backward asymmetry of the b-quark produced in association with a leptonically decaying Z-boson, firstly defined by the candidate, is computed at LO in the 5-flavours number scheme. It is here shown that this observable inherits, from the Polarization Asymmetry of the Z-boson in the same process, stability under factorization/renormalization scale variations and PDF-set choice. For this observable, directly accessible by the LHC experimental collaborations, a complete feasibility study is presented in this work, simulating, with modern tools (MadGraph, PYTHIA, Delphes), both the showering/hadronization processes and the detector response, assuming a final integrated luminosity of 400 fb^-1 with 14 TeV in the center of mass of the colliding proton beams. This allows to determine, for the Forward-Backward asymmetry, an upper bound on the leading experimental systematic and statistical uncertainties at the next LHC run. Finally, the production cross section of a light Higgs boson in association with one b-quark is computed at Next-to-Leading Order in alpha_em in the framework of the Next-to-Minimal Supersymmetric Standard Model. The calculation has been done in the 5FNS, using, respectively, the DRBAR renormalisation scheme to manage Ultraviolet divergencies, and the soft-photon approximation to treat consistently Infrared divergencies. This is the first calculation of the Electromagnetic NLO effect in the NMSSM, which shows a relevant relative magnitude respect to the LO determination of genuinely NMSSM nature.
XXVII Ciclo
1985
Contini, Emanuele. "Galaxy populations in clusters and proto-clusters." Doctoral thesis, Università degli studi di Trieste, 2014. http://hdl.handle.net/10077/9964.
Повний текст джерелаThe aim of my Thesis is to explore the physical properties of the galaxy population in clusters and proto-clusters. A large number of physical processes plays an important role in the formation and evolution of galaxies: cooling, that allows the condensation of gas in the centre of dark matter haloes; star formation, that converts cold gas in stars; feedback from Active Galactic Nuclei (AGN), that prevents the gas in the central regions of haloes from "over-cooling"; feedback from Supernovae, which liberates energy in the surrounding, mixing the gas and enriching it with heavy metals. Galaxy clusters are special environments in which additional important processes take place, and play an important role in the evolution of the cluster galaxy population. Galaxy merging, harassments, tidal interactions, ram pressure stripping and strangulation are all processes acting in dense environments such as clusters of galaxies. I will take advantage of a {\it state of the art}-semi-analytic model of galaxy formation and of a set of 27 high-resolution dark matter only simulations: the semi-analytic model is based on physically motivated and observationally constrained prescriptions for the physical processes listed above and makes use of merger-trees extracted from the simulations to generate mock catalogues of galaxies. First, I make use of this set of simulations to carry out a statistical study of dark matter substructures. In the framework of modern theories of galaxy formation, dark matter substructures can be considered as the birth-sites of luminous galaxies. Therefore, the analysis of subhaloes, and in particular of their mass and spatial distributions, merger and mass accretion histories, provides important information about the expected properties of galaxies in the framework of hierarchical galaxy formation models. I have studied the amount and distribution of dark matter substructures within dark matter haloes, focusing mainly on the measured properties of subhaloes as a function of the mass and physical properties of their parent haloes, and redshift. I show that the fraction of halo mass in substructures increases with increasing mass, reaching $10 \%$ for haloes with mass of the order of $10^{15} \,M_{\odot} \hm$. The scatter in the relation is driven by halo concentration, with less concentrated haloes having larger fractions of mass in substructures. Most of this mass is locateted in the external regions of the parent haloes, in relatively few, but massive subhaloes, thus giving rise to a mass segregation which appears to be stronger at increasing redshift. Tidal stripping is found to be the process responsible for that. In fact, haloes that are more massive at the time of accretion, and that are supposed to host more luminous galaxies, are brought closer to the centre on shorter time-scales by dynamical friction, and therefore suffer of a more significant stripping. The results confirm that the main properties of galaxies, such as luminosity or stellar mass, are related to the mass of subhalos at infall, as found in previous studies.. The main results discussed in this part of the Thesis have been published in Contini et al. (2012), MNRAS.420.2978C. In a second part, I describe the implementation of physical processes responsible for the generation of the Intra-Cluster Light (ICL) in the available semi-analytic model, that, in its original form, does not account for them. The inclusion of these physical processes is, thus, an important improvement of the model. I take advantage of this upgrade of the model to investigate the origin of the ICL and to understand how the main properties of galaxies change with respect to a model that does not include these additional prescriptions. I find the fraction of ICL in groups and clusters predicted by the model to range between $10 \%$ and $40 \%$, with a large scatter and no halo mass dependence. Large part of the scatter on cluster scales is due to a range of dynamical histories, while on smaller scales it is mainly driven by individual accretion events and stripping of relatively massive satellites, with mass of the order of $10^{10.5} \, M_{\odot} \hm$, found to be the major contributors to the ICL. The ICL forms very late, below $ z \sim 1$ and a non negligible fraction (between $5 \%$ and $25 \%$) has been accreted during the hierarchical growth of haloes. Moreover, the ICL is made of stars which cover a relatively large range of metallicity, with the bulk of them being sub-solar, in agreement with recent observational data. The main results of this analysis have been submitted to MNRAS (Contini et al. 2013). In the last part of the thesis, the updated model is used to investigate the properties of the galaxy population in proto-cluster regions. The work is still in progress. I am testing the predictions of the semi-analytic model and comparing them with observations in terms of properties such as galaxy colours, star formation and stellar mass. A preliminary analysis of one very massive proto-cluster region shows that the galaxy population gets red and tend to cluster around the most massive galaxy as time goes by. There are, in literature, only a few attempts to probe such peculiar regions of the Universe from a theoretical point of view. The novelty of this work lies in the connection between massive clusters observed in the local Universe and the proto-cluster regions from which they have formed. I will try to define what a proto-cluster region is, and how it looks like, by studying the main properties of progenitors it contains. Specifically, I will investigate the spatial and velocity distributions of galaxies in simulated proto-clusters, looking at the red and blue galaxy distributions in these regions, as well as at BCG and satellite properties as a function of redshift. The main results of this work will be the subject of a paper in preparation.
XXV Ciclo
1982
Schizzi, Andrea. "Associated production of W bosons and two jets from b quarksat the CMS experiment." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10892.
Повний текст джерелаIl Modello Standard delle particelle elementari è senza dubbio una delle teorie che hanno riscosso il maggior quantitativo di successo nella storia della fisica. La recente scoperta del bosone di Higgs, ad opera degli esperimenti ATLAS e CMS operanti presso il Large Hadron Collider (LHC) di Ginevra, è solamente l’ultima di una lunga serie di predizioni teoriche confermate dall’esperimento. Il meccanismo di produzione di quark b in associazione a bosoni vettori W e Z si inquadra all’interno della fenomenologia del Modello Standard, ma la sua predizione teorica presenta alcune interessanti sfide collegate alla complessità dei calcoli perturbativi nel campo della Cromodinamica Quantistica e alla descrizione del quark b all’interno del protone. Molti sviluppi sono stati fatti di recente in questo contesto tramite lo sviluppo di diversi modelli per la produzione del quark b. Questi risultati presuppongono diverse approssimazioni allo scopo di rendere il calcolo fattibile. La misura della sezione d’urto di produzione per questi processi costituisce quindi un ingrediente importante alla comprensioni di simili processi. Nel presente lavoro, la sezione d’urto per la produzione inclusiva di un bosone vettore W in associazione con una coppia di quark b è stata misurata sfruttando l’insieme di collisioni protone-protone prodotte da LHC ad un energia nel centro di massa pari a 8 TeV. Si è osservato il bosone vettore W tramite il suo decadimento in un elettrone o in un muone ed in un neutrino, mentre ciascun getto adronico originato da un b quark è stati identificato tramite la presenza di un adrone B associato ad un vertice di decadimento secondario. L’analisi è stata effettuata su un campione di collisioni consistente di una luminosità pari a 19.6/fb. La misura della produzione di eventi W+bb è inoltre importante in quanto essa costituisce un fondo irriducibile ad altri processi fisici di grande interesse quali la produzione di W in associazione al bosone di Higgs nel suo canale di decadimento in coppie di quark b. Altri processi del Modello Standard che producono uno stato finale simile al processo studiato nella presente tesi sono costituiti dalla produzione di coppie di quark top , quark top singoli o dalla produzione di coppie di bosoni vettori. Infine, lo stato finale del processo W+bb può costituire un fondo irriducibile per processi di nuova fisica oltre il Modello Standard, quali ad esempio la produzione di particelle supersimmetriche.
The Standard Model of elementary particles is without any doubt one of the most successful theories in the history of physics. The recent discovery of the Higgs boson, thanks to the analysis of the Large Hadron Collider data performed by the ATLAS and CMS experiments, is the last and most striking of a long series of predictions of this theory confirmed by experimental evidence. The production mechanism of bottom quark pairs in association with W or Z vector bosons in proton-proton collisions is comprised within the phenomenology of the Standard Model, but nevertheless its theoretical prediction presents some interesting challenges which are connected with the complexity of perturbative calculations in the context of QCD interactions and with the description of the b quark content of the proton. Many developments have been recently made in this regard with the implementation of several models for the production of b quarks. These results are based on different approximations in order to overcome the difficulties of this calculation. A precise experimental measurement of the production cross section for these processes therefore provides an important input to the refinement of perturbative QCD calculations. In this work, the inclusive production cross section for a W boson and a pair of jets from b quarks is measured using the sample of proton-proton collisions at a center of mass energy of 8 TeV collected by the CMS experiment at the LHC. The W boson is observed via its decay to a muon or electron and a neutrino, while each b-jet is identified by the presence of a B hadron with a displaced secondary vertex. The analysis is performed on a sample of proton-proton collisions corresponding to an integrated luminosity of 19.6/fb. The measurement of the production of W+bb events is also important because this process is an irreducible background to other interesting physics processes involving the production of a Standard Model Higgs boson decaying to a b-jet pair in association with a W. Other Standard Model processes produce final states with a similar experimental signature to the one studied in this thesis, such as the production of top quark pairs, single top quarks or dibosons. Eventually, the final state of W+bb events may mimic the decay of particles predicted by new physics theories beyond the Standard Model, most notably the decay of particles predicted by Supersymmetry.
XXVII Ciclo
1986
La, Licata Chiara. "Measurement of the production cross section of a Z boson in association with exactly one or at least two b jets with the CMS experiment at LHC." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10890.
Повний текст джерелаIl Modello Standard fornisce una delle piu’ soddisfacenti descrizioni delle proprieta’ delle particelle elementari e delle loro interazioni dato il notevole accordo esistente tra le sue predizioni ed i risultati sperimentali conseguiti negli ultimi decenni. Le predizioni teoriche di questo modello sono state verificate in maniera sempre piu’ accurata da numerosi esperimenti ma ci sono ancora alcuni aspetti che non trovano un’ adeguata spiegazione all’interno di questa teoria. Gli esperimenti a LHC si propongono, quindi, di fornire una risposta alle domande rimaste ancora aperte e ai numerosi problemi teorici irrisolti che possono rappresentare un’ indicazione per la presenza di nuova fisica. L’esplorazione di scenari di nuova fisica non puo’, comunque, prescindere da una solida conoscenza dei processi di Modello Standard che possono rappresentare un fondo importante. Per questo motivo i vasti programmi di fisica degli esperimenti di LHC includono anche misure di processi di Modello Standard. Inoltre, lo studio di questi processi e’ importante in quanto rappresentano test fondamentali per le predizioni teoriche di Cronodinamica Quantistica perturbativa. La produzione associata di bosoni Z in associazione con uno o piu’ getti provenienti dall’adronizzazione di quark pesanti fornisce un test unico per alcune predizioni teoriche. Questo lavoro di tesi verte sullo studio della produzione associata di un bosone Z con esattamente un getto di tipo b o almeno due getti di tipo b. Per eseguire questa misura sono stati usati i dati forniti nel 2012 da LHC ad una energia del centro di massa di 8 TeV e raccolti dall’esperimento CMS (corrispondente ad una luminosita’ integrata di 19.8 fb−1). La prima parte dell’analisi e’ incentrata sulla selezione degli eventi: specifiche richieste su alcune variabili vengono applicate per discriminare la segnatura Z+b. I diversi contributi dei fondi sono estratti da simulazioni Monte Carlo fatta eccezione per il fondo da quark top che e’ stato valutato dai dati. Particolare attenzione e’ stata posta per estrarre la purezza dell’evento, ovvero stimare il vero numero di getti di tipo b. Questo e’ stato fatto simultaneamente nei campioni selezionati Z + 1b e Z + 2b per poter tenere conto di possibili migrazioni di eventi da un campione all’altro a causa di inefficenze dell’algoritmo usato per l’identificazione del tipo di getto. Per poter confrontare i risultati sperimentali ottenuti con i calcoli teorici e’ necessario correggere le quantita’ misurate dagli effetti del rivelatore. Diverse sorgenti di incertezze sistematiche sulla misura sono state, infine, studiate. Le sezioni d’urto differenziali misurate in funzione di diverse osservabili sono state quindi confrontate con diverse predizioni teoriche che implementano diverse approcci nel calcolo (schema 4-flavor, schema 5-flavor).
XXVII Ciclo
1984
Sammito, Davide. "Integration of plasmonic gratings into optoelectronic devices." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8578.
Повний текст джерелаABSTRACT This thesis deals with the control of light absorption in semiconductor devices by the plasmonic resonances of periodically arranged metallic nanostructures integrated on them. Metallic gratings support propagating (SPP) and localized (LSP) plasmonic excitations and surface plasmons-related phenomena, like Extraordinary Optical Transmission (EOT) and plasmonic band gaps, as well as conventional diffraction effects. We combine all the optical resonances outlined to tune the incoupling and distribution of incident photons in the absorbing semiconductor substrate. In particular we consider the application of these concepts to two typologies of optoelectronic devices: photovoltaic solar cells and phototransistors. In the case of photovoltaic devices the objective is to increase the energy conversion efficiency by enhancing light harvesting and re-shaping the absorption profile, in order to improve the collection of photo-generated charge carriers. We begin analyzing a case study, a one-dimensional lamellar grating placed on a silicon substrate, by numerical optical simulations. The aim is to find the coupling conditions of the resonances supported, by designing the geometric parameters of the nanostructures, and showing their impact on the generation profile. These findings are then applied for light trapping purpose to two realistic solar cell layouts. SPP and LSP resonances are able to provide high near field magnification and effectively enhance the absorption of ultrathin organic solar cells. On the other hand, EOT coupled to diffraction orders are more suited to wafer-based Si cells. Then we present the fabrication process developed to realize the designed nanostructures over the large surface area of Si photovoltaic devices. By experiments and simulation we show that an improvement of Internal Quantum Efficiency can be obtained compared to unpatterned devices. Concerning the phototransistors, the aim is use them as compact and scalable biosensors by integrating a plasmonic crystal on the active area. By simulations the grating is designed to maximize transmittance variation due the plasmon resonance shift related to the surface binding of bio-analyte molecules. This event is transduced into an electrical signal at device terminals, as confirmed by characterizations on the first prototypes fabricated. The metallic grating simultaneously works as plasmonic structure and as electronic gate of the transistor in a fully integrated architecture.
SOMMARIO In questa tesi viene trattata la tematica del controllo dell’assorbimento di luce in dispositivi a semiconduttore tramite le risonanze plasmoniche proprie di nanostrutture metalliche integrate con disposizione periodica. Reticoli metallici supportano eccitazioni plasmoniche propaganti (SPP) e localizzate (LSP) e fenomeni correlati ai plasmoni di superficie, quali la trasmissione ottica straordinaria (EOT) e la creazione band gap plasmoniche, così come effetti di diffrazione convenzionali. Tali risonanze ottiche sono state combinate per regolare l’accoppiamento e la distribuzione dei fotoni incidenti in substrati semiconduttori assorbenti. In particolare consideriamo l’applicazione di tali concetti a due tipologie di dispositivi optoelettronici: celle solari fotovoltaiche e foto-transistor. Nel caso dei dispositivi fotovoltaici, l’obiettivo è aumentare l’efficienza di conversione energetica tramite una maggiore raccolta di luce e la redistribuzione del profilo di assorbimento, in modo da migliorare la raccolta dei portatori di carica fotogenerati. L’analisi di un caso di studio, un reticolo lamellare monodimensionale posto su un substrato di silicio, tramite simulazioni ottiche per via numerica, serve a trovare le condizioni di accoppiamento delle risonanze supportate, dimensionando i parametri geometrici delle nanostrutture, e mostrare il loro impatto sul profilo di generazione. Questi risultati sono quindi applicati, per finalità di “light trapping”, a due strutture realistiche di celle solari. Le risonanze SPP e LSP sono capaci di fornire una grande intensificazione del campo vicino e aumentano efficacemente l’assorbimento di celle solari organiche ultra-sottili. D’altro canto, la combinazione di EOT e ordini di diffrazione è più adatta per celle solari spesse in Si. Quindi presentiamo il processo di fabbricazione sviluppato per realizzare le nanostrutture progettate sulle ampie superfici dei dispositivi fotovoltaici in Si. Esperimenti e simulazioni mostrano che è possibile ottenere un aumento dell’efficienza quantica interna rispetto ai dispositivi non nanostrutturati. Per quanto riguarda i foto-transistor, l’obiettivo è utilizzarli come biosensori compatti e scalabili tramite l’integrazione di cristalli plasmonici sull’area attiva. Il reticolo è stato progettato in modo da massimizzare variazioni di trasmittanza dovute alla modulazione delle risonanze plasmoniche indotta dal legame di bio-molecole sulla superficie. Questo evento è trasdotto in un segnale elettrico misurabile ai capi del dispositivo, come confermato dalle caratterizzazioni sui primi prototipi fabbricati. Il reticolo metallico funziona simultaneamente come struttura plasmonica e come gate elettronico del transistor in un’architettura totalmente integrata.
XXV Ciclo
1984
Книги з теми "SCUOLA DI DOTTORATO DI RICERCA IN FISICA"
Arcuri, Alberto. Sicurezza integrata e welfare di comunità. Edited by Tommaso Giupponi. Fondazione Bologna University Press, 2022. http://dx.doi.org/10.30682/sg314.
Повний текст джерелаSpiga, Federico. Il corpo tra infanzia e adolescenza. Bononia University Press, 2020. http://dx.doi.org/10.30682/alph01.
Повний текст джерела