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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

[pt] ESTUDOS DE SENSIBILIDADE PARA VIOLAÇÃO DE CARGA-PARIDADE NOS DECAIMENTOS D+ -> K-K+Π+ E D+ -> Π-Π+Π+ NO EXPERIMENTO LHCB / [en] SENSITIVITY STUDIES FOR CHARGE-PARITY VIOLATION IN THE DECAYS D+ -> K-K+Π+ AND D+ -> Π-Π+Π+ IN THE LHCB EXPERIMENT

LUCAS NICHOLAS FALCAO FERREIRA 11 January 2022 (has links)
[pt] Na última década, desde o início do funcionamento do LHC, o Modelo Padrão de física de partículas vem sendo posto à prova com precisão sem precedentes, com enorme êxito. Um de seus experimentos é o LHCb, dedicado à física dos hádrons contendo os quarks beauty e charm. Um dos importantes temas de pesquisa do LHCb é o estudo de efeitos de assimetria partícula-antipartícula em processos de decaimento, devido à chamada violação de Carga-Paridade (CP). A violação de CP é prevista pelo Modelo Padrão e, em decaimentos envolvendo o quark charm, pode ocorrer em certos processos chamados de suprimidos por Cabibbo. No entanto, este efeito é muito pequeno, da ordem de 0.1 porcento. Esta pequenez faz com que o ambiente de decaimentos charmosos seja atraente para busca por física além do Modelo Padrão. O objetivo deste trabalho é o estudo de sensibilidade para violação de CP nos canais D+ -> K- K+π+ e D+ -> π- π+π+: no run II do LHCb. Através de uma representação do espaço de fase desses decaimentos, chamado de Dalitz Plot, e a utilização do método de Mirandizing, que se baseia em procurar significâncias locais na diferença da distribuição de eventos no Dalitz Plot de partícula e antipartícula, pode-se buscar por assimetrias de carga que indicariam efeitos de violação de CP nestes decaimentos. Baseando-se nas estatísticas dos dados tomados entre 2016 e 2018 no LHCb, foram desenvolvidos pseudoexperimentos, via método de Monte Carlo, visando reproduzir a dinâmica dos dados reais, e inserindo pequenos efeitos de violação de CP. Verificamos que há sensibilidade para a violação de CP com efeitos da ordem de 10-3 em algumas situações, que condiz com as expectativas do Modelo Padrão, o que indica a possibilidade de observação de violação de CP nos dados reais do run II. / [en] In the last decade, since the beginning of the operation of the LHC, the Standard Model of particle physics has been tested with unprecedented precision, with enormous success. One of its experiment is LHCb, dedicated to the physics of hadrons containing the beauty and charm quarks. One of the important research topics of the LHCb is the study of the effects of particle-antiparticle asymmetry in decay processes, due to the so-called charge-parity violation (CP). CP violation is predicted by the Standard Model and, in decays involving the charm quark, it can occur in certain processes called Cabibbo-suppressed. However, this effect is very small, of the order of 0.1 percent. This smallness makes the environment of charm decays attractive to search for physics beyond the Standard Model. The aim of this work is the study of sensitivity for CP violation in the channels D+ -> K-K+π+ and D+ -> π-π+π+ in run II of the LHCb. Through the phase space of these decays, called Dalitz Plot, and the use of the Mirandizing method, which is based on looking for local significance in the difference in the distribution of events for particle and antiparticle Dalitz Plots, one can seek for local asymmetries that would indicate effects of CP violation in these decays. Based on the data statistics taken between 2016 and 2018 at the LHCb, pseudo experiments were performed, using the Monte Carlo method, aiming to reproduce the dynamics of real data, and inserting small effects of CP violation. We found that there is sensitivity for CP violation with effects of the order of 10−3 in some situations, which is the expected level predicted by the Standard Model, indicating a possibility for observing CP violation in the real data from run II.
502

Redovisningsetik : En studie som undersöker hur företagsskandaler framställsi media / Accounting ethics : A study that examines how corporate scandals are portrayed by media

Hadgebes, Nebay, Magan, Hanna, Teklemariam Haile, Yosan January 2022 (has links)
Media is something the public comes in contact with on a daily basis. Through numerous platforms, their overall goal is to spread information, messages, and pique interest. The power that the media has also means that they have a great influence on the public's perceptions and opinions about what is right and wrong. At the same time, social media has also become an increasingly common approach to spread information in a faster way than before.   This study aims to investigate how corporate scandals are portrayed by the media. Furthermore, this study aims to examine how the media's reporting of corporate scandals has changed over the years. The study has adopted a social constructivist research approach as the study touches on what is considered right and wrong from an ethical perspective. The study is a document study that examines three different corporate scandals based on 105 Swedish articles. Each corporate scandal has 35 articles designed in three tables. The 105 Swedish articles are news articles from various morning- and evening newspapers.  A conclusion drawn in the study is that only one of the articles refers to social media and that social media thus has a low impact on the media reporting of these scandals. This is partly due to the fact that two of the scandals investigated took place during a period where social media was not as developed as it is today, but the third is important to point out the reason why social media influence exists at the time of the scandal. Furthermore, it is also concluded that it is primarily the company management who were portrayed as the culprits by the media, and that the focus shifted from the organization in question. The absence of social media means that only traditional media sources controls the story of the corporate scandals.This is clearly shown among the articles as they focus on blaming the individuals behind the scandals in order to apply the idea of the guilty towards the innocent which piques a greater interest and thus generates more income  A proposal for further research includes examining articles internationally in order to determine how they may differ from Swedish media and also to be able to shed light on the factors behind the differences.  This study is written in swedish / Media är något allmänheten kommer i kontakt med dagligen. Via olika plattformar är deras övergripande mål primärt att sprida information, budskap, och väcka intresse. Denna makt som media behärskar innebär även att de har en stor påverkan på allmänhetens uppfattningar och åsikter kring vad som är rätt och fel. Samtidigt har även sociala medier blivit ett alltmer vanligare tillvägagångssätt för att sprida information på ett snabbare sätt än tidigare. Syftet med studien är att undersöka hur olika företagsskandaler framställs i media. Vidare syftar studien även till att undersöka hur medias rapportering av företagsskandaler förändrats genom åren. Studien har antagit en socialkonstruktivistiskt forskningsansats då studien berör vad som anses rätt och fel ur ett etiskt perspektiv. Studien är en dokumentstudie som undersöker tre olika företagsskandaler utifrån 105 svenska artiklar. Varje företagsskandal har 35 artiklar utformade i varsin tabell. De 105 svenska artiklarna är nyhetsartiklar från diverse morgon – och kvällstidningar.   En slutsats som dras i studien är sociala medier och dess påverkan på medias framställning av skandaler är svag eftersom endast en av de berörda artiklarna refererar till sociala medier.  Detta beror delvis på att två av de undersökta företagsskandalerna skedde under en period där sociala medier inte var lika utvecklat i den grad som den är idag, men den tredje är viktig att poängtera av den orsaken att sociala mediers påverkan existerade vid skandalens tidpunkt. Vidare dras även slutsatsen att det primärt är företagsledningen som framställs som de skyldiga av media, och att fokuset försvann från organisationen i fråga. Sociala mediers frånvaro bland rapporteringen innebär att enbart traditionell media styr narrativet av företagsskandalerna. Detta visas tydligt bland artiklarna då de fokuserar på att skuldbelägga individerna bakom skandalerna för att kunna applicera idén om de skyldiga gentemot de oskyldiga som väcker ett större intresse och därmed genererar fler intäkter.   Ett förslag på vidare forskning inkluderar att undersöka artiklar internationellt för att kunna avgöra skillnader gentemot svensk media och även kunna belysa de faktorer som ligger bakom skillnaderna.  Studien är skriven på svenska
503

Shihua_Huang_thesis_Dec_2022_submit.pdf

Shihua Huang (14226611) 08 December 2022 (has links)
<p>The ability of the Mu2e experiment to probe, or discover BSM physics in direct CLFV μ+ and π+ decay modes is estimated.</p>
504

Leptonic Dipole Transitions: A New Signature for Physics Beyond the Standard Model

Tunley, Robin 04 1900 (has links)
<p>In this work, we consider the addition of a single neutral massive vector boson to the Standard Model (SM). This boson, which we refer to as N<sup>0</sup>, induces dipolar transitions between electrons and muons. We obtain bounds on the strength of its coupling and its mass: from the scattering process e+e- to mu+mu-; from its contribution to muonium-antimuonium oscillations; and from its possible contribution to the rare muon decay mu- to e+e-e-. In particular, we examine the two cases where the mediator is both heavy and light compared with the scattering energies for, and place constraints on the relevant parameters based on their contributions to the cross section and the forward-backward asymmetry. For muonium-antimuonium oscillations, we consider only the case where the mediator is heavy compared to all other scales, reducing its effect to an effective contact interaction. Finally, we consider an SU(2) invariant theory from which the N<sup>0</sup> interaction emerges, and find that flavour diagonal interactions also emerge, giving a tree-level path for the decay mu- to e+e-e-. We find that the heavy N<sup>0</sup> is not strongly constrained by this contribution, while the light N<sup>0</sup> is very strongly constrained by it. Very generally, we find that the heavy N<sup>0</sup> is much less constrained than other lepton flavour violating processes, while the constraints on the light N0 vary in strength between processes.</p> / Master of Science (MSc)
505

[en] RESTRICTING THE VIOLATION OF EQUIVALENCE PRINCIPLE BY ICECUBE S ATMOSPHERIC NEUTRINO DATA / [pt] RESTRINGINDO A VIOLAÇÃO DO PRINCÍPIO DA EQUIVALÊNCIA COM DADOS DE NEUTRINOS ATMOSFÉRICOS DO ICECUBE

LIZANDRA MINEIRO CAMPOS CHAGAS 27 August 2024 (has links)
[pt] O princípio da equivalência é um pressuposto fundamental da Teoria da Relatividade Geral, entretanto, nas tentativas de quantização da gravidade os cálculos estão levando, muitas vezes, a pequenas violações desse princípio (VEP). Por esse motivo, se mostra necessário testá-lo e obter limites estatísticos para essas violações, a fim de possivelmente descartar alguns cenários. Uma das frentes com grande possibilidade de limitar os valores dessa violação é analisando a oscilação de neutrinos atmosféricos de altas energias, gerados pelos raios cósmicos. A oscilação padrão de sabores dos neutrinos que atravessam a Terra se torna desprezível em altas energias, enquanto a oscilação induzida por VEP se torna cada vez mais proeminente nessa faixa da energia. Neste trabalho, usamos uma abordagem minimalista da VEP, em que ela aconteceria através de diferentes valores de constantes gravitacionais para cada autoestado de massa de neutrino, parametrizado como Gi ≡ γiG onde o G é contante gravitacional, e traçamos limites para os parâmetros \Phi \Delta\gamma_21 e \Phi \Delta\gamma_21 no plano (\Phi \Delta\gamma_21 , \Phi \Delta\gamma_31), onde o \Phi é o potencial gravitacional. Para isso, foram usados os dados de rastros de múons gerados da interação de neutrinos atmosféricos com a rocha ou gelo, coletados por um ano pelo IceCube na sua forma completa (IC-86). Os múons possuem energias entre 400 GeV e 20 TeV, e os dados coletados foram comparados com os valores esperados pelos melhores modelos de produção de neutrinos muônicos atmosféricos. / [en] The equivalence principle is a fundamental assumption of General Relativity. However, in several quantum gravity scenarios, small violations of thisprinciple (VEP) is expected. For this reason, it is important to test this principle and obtain statistical limits on its violation, in order to possibly discardsome scenarios. One way to constrain this violation is analyzing the flavor oscillation pattern of high-energy atmospheric neutrinos, generated by cosmicrays. The standard oscillation of neutrino s flavor crossing the Earth becomesnegligible at high energies, while the oscillation induced by VEP becomes increasingly prominent in this range of energy. In this work, we use a minimalisticapproach about the VEP, in which it would occur because of different valuesof gravitational constants for each neutrino mass eigenstate, parameterized asGi ≡ γiG where G is the gravitational constant, and we derive limits on theparameters Phi Deltagamma_21 and Phi Deltagamma_21 in the (Phi Deltagamma_21 , Phi Deltagamma_31) plane, where Phi is thegravitational potential. To this end, muon-tracks events generated from theinteraction of atmospheric neutrinos with the rock or ice, collected for oneyear by IceCube in its complete form (IC-86), were used. The detected muonshave energies between 400 GeV and 20 TeV, and the collected data has beencompared with the values expected by the best models of atmospheric muonneutrino production.
506

A study of charge symmetry violation in fragmentation functions extracted from semi-inclusive electroproduction of charged pions from protons and deuterons

Bhatt, Hem Datt 10 May 2024 (has links) (PDF)
We have measured the flavor dependence of multiplicities for $\\pi^+$ and $\\pi^-$ production in semi-inclusive deep-inelastic scattering (SIDIS) on proton and deuteron targets. We used a 10.6 GeV electron beam at Jefferson Lab, and 4 msr solid angle spectrometers (HMS for electrons, SHMS for pions), the lepton vertex spanned the kinematic range $0.3 < x < 0.6$, $2 < Q^2 < 5$ GeV$^2$, and $4 < W^2 < 11$ GeV$^2$. The pion fractional momentum range was $0.3 < z < 0.7$ and the small transverse momentum range was $0 < P_t < .25$ GeV. We used the multiplicities to form sum-and-difference ratios, testing the validity of factorization. We extracted two favored and two unfavored $W$ dependent fragmentation functions (FFs) from these multiplicities. Assuming factorization at low $P_t$, we find that the two ``favored" FFs allow for isospin breaking (charge symmetry violation) at low $W$, while converging to a common value at the highest $W$ of this experiment. The two unfavored FFs are consistent with each other within the experimental uncertainties.
507

Études de la violation de CP dans les désintégrations B0 -> DK*0 et des performances du système de déclenchement hadronique avec le détecteur LHCb au CERN / CP violation studies on the B0 -> DK*0 decays and hadronic trigger performance with the LHCb detector at CERN

Martin Sanchez, Alexandra 25 June 2013 (has links)
Dans le Modèle Standard de la physique des particules, le mécanisme Cabibbo-Kobayashi-Maskawa (CKM) décrit le phénomène du mélange des quarks. De ses paramètres, l'angle gamma est celui connu avec la moins grande précision. Les mesures directes donnent une incertitude d'environ 15º, importante comparée à celle sur la valeur extraite des ajustements globaux, de 3º. Pour vérifier la cohérence du Modèle Standard, gamma doit être mesuré précisément. Cela est possible en utilisant des processus au niveau des arbres, où seules des contributions du Modèle Standard sont attendues, ou avec des processus impliquant des boucles, qui peuvent être sensibles à des effets au-delà. Des différences entre la mesure de gamma avec des diagrammes en arbres et avec des boucles pourraient être donc une indication de nouvelle physique. Cette thèse présente la première mesure des observables CP dans la désintégration B0 -> DK*0. Celle-ci est sensible à gamma du fait de l'interférence entre l'amplitude des diagrammes b -> u et b -> c, au niveau des arbres. L'asymétrie CP dans le mode B0 -> D(K+K-)K*0 et le rapport des largeurs partielles avec B0 -> D(K+pi-)K*0 sont mesurés avec 1 /fb de données récoltées par l'expérience LHCb en 2011,A_KK_d = -0,452 +/- 0,230 +/- 0,025 = A_CP+,R_KK_d = 1,360 +/- 0,366 +/- 0,075 = R_CP+. L'asymétrie CP du mode supprimé B0 -> D(K-pi+)K*0 et le rapport des largeurs partielles avec le favorisé B0 -> D(K+pi-)K*0 sont mesurés avec 3 /fb de données récoltées en 2011 et 2012,A_sup_d = -0,094 +/- 0,318 = A_ADS,R_d = 0,075 +/- 0,023 = R_ADS. Les études réalisées sur le système de déclenchement hadronique de l'expérience LHCb sont aussi présentées. / In the Standard Model of particle physics, the Cabibbo-Kobayashi-Maskawa (CKM) mechanism describes the quark mixing effect. The CKM gamma angle is one of the parameters of the Standard Model that are known less accurately. Direct measurements give an uncertainty of around 15º, large with respect to the uncertainty on the value extracted from global fits, of 3º. In order to test the Standard Model consistency, the gamma angle needs to be measured precisely. This can be done using processes at the tree-level, where only Standard Model contributions are expected, or using processes involving loop diagrams, which can be sensitive to physics beyond the Standard Model. Differences in the gamma measurement from tree and loop diagrams would be an indication of new physics. This thesis presents the first measurement of the CP observables in the B0 -> DK*0 decay. Sensitivity to gamma arises from the interference of the b -> u mediated amplitude with the b -> c one, at the tree-level. The CP asymmetry of the B0 -> D(K+K-)K*0 mode and the partial width ratio of this channel with respect to B0 -> D(K+pi-)K*0 are measured using 1 /fb of data collected by the LHCb experiment in 2011,A_KK_d = -0.452 +/- 0.230 +/- 0.025 = A_CP+,R_KK_d = 1.360 +/- 0.366 +/- 0.075 = R_CP+. The CP asymmetry of the suppressed B0 -> D(K-pi+)K*0 mode and the partial width ratio with respect to the favoured B0 -> D(K+pi-)K*0 are measured using the total 3 /fb of data collected in 2011 and 2012,A_sup_d = -0.094 +/- 0.318 = A_ADS,R_d = 0.075 +/- 0.023 = R_ADS. In addition, the studies performed on the hardware hadronic trigger of the LHCb experiment are also presented.
508

Le rôle du droit international dans l'émergence d'un Etat palestinien. Difficultés et limites / The role of international law in the emergence of a palestinian state. Difficulties and limits

Suleiman, Lourdes 04 July 2014 (has links)
La communauté internationale et le droit international sont confrontés à un défi majeur : trouver une solution mettant un terme au conflit israélo-palestinien. L’étude du conflit israélo-palestinien à la lumière du droit international montre les nombreuses difficultés relatives à l’émergence d’un Etat palestinien. En effet, ce dernier est une source de violation du droit international du fait notamment des manquements aux droits fondamentaux qui ne cessent de sévir sur ce territoire. Les violations commises à l’encontre du droit international remontent à l’époque du mandat britannique et sont finalement caractérisées par l’impunité des entités qui les ont commises. Cela permet donc de mettre en évidence les lacunes où même les faiblesses du droit international, plus précisément celles de l’ONU qui se trouve en difficultés face à un manquement constant à ces principes et à ces décisions. On a cherché à pallier à cette situation infernale par l’usage de techniques qu’offre le droit international dont l’objectif est de mettre un terme à un conflit. Il existe une technique qui paraît être la plus appropriée pour le conflit israélo-palestinien, il s’agit de la fameuse technique de la négociation. Cependant le processus de paix ayant débuté en 1990 se trouve aujourd’hui presque oublié.Malgré tout cela, la création d’un Etat palestinien se trouve être la base de la solution du conflit israélo-palestinien. Cette présente étude cherche à démontrer, sur la base de la définition de l’Etat selon le droit international, que la Palestine dispose d’une part, d’éléments avérés, mais imparfaits, permettant à cette dernière de constituer un Etat selon le droit international, et d’autre part que cette dernière ne peut accéder au rang d’Etat dans la mesure où certains éléments nécessaires à la constitution d’un État demeurent contestables. Ce qui manque à la Palestine pour se constituer en Etat c’est l’effectivité. / The international community and the international law are facing a great challenge: find the solution to end the Israeli-Palestinian conflict. The study of the Israeli-Palestinian conflict in light of international law shows many difficulties related to the emergence of a Palestinian state. Indeed, this conflict is a source of violation of international law specifically a violation of human rights that continues to strike in this area. Violations against international law go back to the time of the British mandate and are finally characterized by the impunity towards the entities that have committed them. Therefore, this allows us to highlight the weaknesses of international law, more specifically those of the United Nations that is confronted with the constant breach of its principles and decisions. We have tried to overcome this infernal situation by using the techniques offered by the international law that aims to put an end to a conflict. There is a technique that seems to be the most appropriate for the Israeli-Palestinian conflict known as the negotiation. However, the peace process that began in 1990 is now almost forgotten.Despite all this, the creation of a Palestinian state is the base to the solution of the Israeli-Palestinian conflict. This present study aims to demonstrate, based on the definition of the State under international law, that Palestine has, on one hand, confirmed elements/components that are imperfect, allowing the latter to constitute a State under international law, and on the other, that it can’t achieve statehood to the extent that certain elements necessary for statehood remain questionable. What Palestine is missing is effectiveness.
509

ASSINATURAS DA VIOLAÃÃO DA SIMETRIA DE LORENTZ NA RADIAÃÃO CÃSMICA DE FUNDO / SIGNATURES OF LORENTZ OF SYMMETRY VIOLATION IN BACKGROUND COSMIC RADIATION

Arilo Pinheiro AraÃjo 02 August 2016 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho investigaremos a relaÃÃo da violaÃÃo da simetria de Lorentz com a anisotropia da radiaÃÃo cÃsmica de fundo. Exporemos o desenrolar da compreensÃo do Big Bang e tambÃm da radiaÃÃo em questÃo e mostraremos o seu significado e a sua natureza. Mostraremos as definiÃÃes de simetria de Lorentz e de violaÃÃo da simetria de Lorentz. Usaremos o modelo Bumblebee para lidar com os termos que violam essa simetria e mostraremos quais termos serÃo utilizados. Desenvolveremos uma equaÃÃo de Einstein modificada atravÃs da variaÃÃo, com respeito à mÃtrica, da aÃÃo de Einstein-Hilbert com os termos de Bumblebee adicionados, pois sÃo os termos que violam a simetria de Lorentz. Usaremos essa equaÃÃo desenvolvida para fazer uma anÃlise perturbativa. Usaremos a mÃtrica de Friedmann-LemaÃtre-Robertson-Walker, por ser uma mÃtrica isotrÃpica, e introduziremos uma perturbaÃÃo em cada direÃÃo da parte espacial da mÃtrica em questÃo para tornÃ-la anisotrÃpica. Por fim, apresentaremos um conjunto de quatro equaÃÃes diferenciais lineares acopladas (com as perturbaÃÃes como variÃveis) que relacionam as perturbaÃÃes propostas com o campo de Bumblebee. / Neste trabalho investigaremos a relaÃÃo da violaÃÃo da simetria de Lorentz com a anisotropia da radiaÃÃo cÃsmica de fundo. Exporemos o desenrolar da compreensÃo do Big Bang e tambÃm da radiaÃÃo em questÃo e mostraremos o seu significado e a sua natureza. Mostraremos as definiÃÃes de simetria de Lorentz e de violaÃÃo da simetria de Lorentz. Usaremos o modelo Bumblebee para lidar com os termos que violam essa simetria e mostraremos quais termos serÃo utilizados. Desenvolveremos uma equaÃÃo de Einstein modificada atravÃs da variaÃÃo, com respeito à mÃtrica, da aÃÃo de Einstein-Hilbert com os termos de Bumblebee adicionados, pois sÃo os termos que violam a simetria de Lorentz. Usaremos essa equaÃÃo desenvolvida para fazer uma anÃlise perturbativa. Usaremos a mÃtrica de Friedmann-LemaÃtre-Robertson-Walker, por ser uma mÃtrica isotrÃpica, e introduziremos uma perturbaÃÃo em cada direÃÃo da parte espacial da mÃtrica em questÃo para tornÃ-la anisotrÃpica. Por fim, apresentaremos um conjunto de quatro equaÃÃes diferenciais lineares acopladas (com as perturbaÃÃes como variÃveis) que relacionam as perturbaÃÃes propostas com o campo de Bumblebee.
510

Study of the time-dependent CP asymmetry in D° decays in the Belle II experiment / Etude de l'asymétrie de CP en fonction du temps dans les désintegrations du méson D° dans l'expérience Belle II

Maria, Robert Daniel 30 October 2015 (has links)
Nous étudions la sensibilité de Belle II avec 50 ab-1 de données sur l'angle βc du triangle d'unitarité, avec une mesure en fonction du temps de l'asymétrie de CP dans les désintégrations des mésons D0. Nous montrons que cette mesure est limitée statistiquement, avec une incertitude totale attendue de l'ordre de 3°. La mesure de βc nécessite la reconstruction de trajectoires de particules de très faible impulsion, impactée par le bruit de fond induit par SuperKEKB. Deux échelles PLUME vont être utilisées pour étudier ce bruit de fond. Ici, une étude des performances de PLUME est effectuée. Ainsi, la résolution spatiale avec des traces à 0° et 36° est mesurée, de 1,8 µm et 3,5µm respectivement. Par ailleurs nous proposons d'améliorer la mesure des faibles impulsions en utilisant la charge déposée par la particule dans le trajectomètre interne au silicium. L'estimateur permet d'améliorer par 2% la résolution sur l'impulsion pour les particules n'atteignant pas le trajectomètre interne. / We are studying the sensitivity of Belle II with 50 ab-1 data to the βc angle of the c-u unitarity triangle, with a time-dependent measurement of the CP asymmetry in the D0 decays. We show that such a measurement is still statistically limited, with a total expected incertitude of 3°.This measurement relies on the reconstruction of soft momenta, impacted by the SuperKEKB induced background.Two PLUME ladders will be used to study this background, therefore a study on the performances of PLUME was performed. The spatial resolution is of 1.8 µm and 3.5 µm for 0° and 36° tilted tracks respectivelly.We also propose to improve the estimation of soft momenta using the energy depositions of charged particles in the silicon layers of the inner tracker. Our estimator improves by approximately 2 % the resolution on momentum for particles which do not penetrate the central tracking system.

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