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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.
51

Analýza volné produkce charm kvarku v difrakční fotoprodukci s elastickým protonem v koncovém stavu na HERA / Analysis of Diffractive Open Charm Photoproduction with a Leading Proton at HERA

Jansová, Markéta January 2015 (has links)
The diffractive open charm production is studied using data from 2006-2007, when the leading proton measurement by H1 Very Forward Proton Spectrometer was provided. The charm production is tagged by the decay products of D∗ meson. The cross section of e+ p → e+ D∗ X p in photoproduction regime defined by the value of virtuality Q2 < 2 GeV is determined and corrected for the detector effects. The diffractive D∗ meson photoproduction cross section is compared with the hadron level MC Rapgap prediction based on diffractive parton distribution functions extracted from inclusive ep DIS measurements. Measurement of leading proton provides a unique opportunity to investigate the response of forward detectors for the diffractive events. Using such events, the performance of the large rapidity gap selection is examined.
52

Analysis of Simulated Charm Baryons : Decay Kinematics and Parameter Estimations for Studies with the Belle II Experiment

Spengler, Elsa, Bjursten, Sara January 2023 (has links)
A fundamental assumption of our universe has been that equal amounts of matter and antimatter were created during the Big Bang. Since the world we live in is made entirely of matter, one either needs to question this assumption, or explain how matter was enriched with respect to antimatter. This is a puzzle that scientists all over the world are trying to solve. Particle accelerator experiments like Belle II in Tsukuba, Japan, enable precision studies of the heavier siblings of protons, for example charmed baryons. Since these baryons are unstable, they offer a unique tool to understand the matter-antimatter-asymmetry of the universe: by comparing the decay-patterns of the baryons and antibaryons, we look for tiny differences in the interactions that, if they exist, can have led to the matter-antimatter imbalance. The project aims to examine the capacity of the Belle II generator, which is a crucial part of analysis in experimental particle physics. The aim of this project is also to develop a toolkit for estimating decay-parameters from baryon decay distributions: one single-step process and one multi-step process, and compare statistical properties of the estimators in order to see which one yields a more precise estimation.
53

Measurement of branching fraction and search for CP violation in D0 → Ks0 Ks0 π+ π- decays at Belle experiment

Sangal, Aman January 2022 (has links)
No description available.
54

Non-photonic Electron Distributions at Pseudo-rapidities Between 1.1 and 1.5 in Proton-Proton Collisions at √s=200 GeV at Relativistic Heavy Ion Collider

Subba, Naresh L. 19 July 2010 (has links)
No description available.
55

Charmed Meson Measurements Using a Silicon Tracker in Au+Au Collisions at sqrt{S<sub>NN</sub>} = 200 GeV in STAR Experiment at RHIC

Ajish, Jaiby J. 28 November 2011 (has links)
No description available.
56

Search For Radiative Decays Of D<sup>0</sup> Mesons At The Babar Detector

Regensburger, Joseph James 29 July 2008 (has links)
No description available.
57

Triangle Singularities in the Production of the X(3872) Resonance

He, Liping January 2021 (has links)
No description available.
58

Male entrapment and its charm warrant: A systematic review characterising male entrapment behaviours of domestic abuse, how they are described and researched

Moore, Nikki, Branney, Peter, Edwards, Lisa, Ojofeitmi, Oluyemisi 16 October 2024 (has links)
Yes / Background: Research and policy traditionally focus on female victim-survivors of domestic abuse. Therefore, behaviour change approaches for male perpetrators of abuse look at the same, rather than focusing on the root cause of the problem — men who use abusive behaviours. This systematic review aimed to identify studies that characterise entrapment behaviours and how male perpetrators describe those behaviours. Method: The review used a systematic meta-analysis design, conducting an electronic search via databases with a two-stage strategy employed to locate literature and pinpoint key themes and concepts to explore coercive control and male entrapment behaviours of domestic abuse. The protocol was pre-registered on PROSPERO. Nine articles were identified within the review as being of interest, and this paper provides a narrative synthesis which details the results of the systematic review. Results: The narrative synthesis identified unities between some articles, which were labelled as commonalities. There are four commonalities: male behaviour, coercive control, charm and charisma and power. Critically the review only returned one article directly examining male behaviours of entrapment, with the findings still valid a decade later, but shows more research needs to be built upon this. Conclusion: This review showed that male behaviour within domestic abuse is chronically under-researched, and behaviours utilised by male perpetrators of abuse to entrap and coercively control a female partner need further investigation, but that charm and power is an area of interest.
59

Study of Rare Charm Decays with the LHCb Detector at CERN / Etude de désintégrations charmées rares avec le détecteur LHCb au CERN

Kochebina, Olga 19 September 2014 (has links)
Les désintégrations charmées rares interviennent principalement via des courants neutres changeant la saveur (FCNC). Le Modèle Standard (SM) n'autorise les courants qu'au niveau des boucles. Dans les désintégrations du charme, les FCNC sont sujets à une très efficace suppression de GIM. Des processus très rares sont donc à considérer. Ils sont d'excellents outils pour la recherche Nouvelle Physique (NP) au-delà du SM. Les particules de NP pourraient devenir détectables en écartant des observables telles que des rapports de branchement et des asymétries CP et angulaires prévisions de le SM. Le sujet principal de cette thèse est la mesure du rapport de branchement D0->K-π+ρ/ω(->µ+µ-). Il sera précieux en particulier en tant que mode de normalisation lors de l'étude de toutes les désintégrations D0 -> h-h’+ µ+µ- : D0 -> K-π+µ+µ-, D0 -> π+π-µ+µ-, D0 -> K+K-µ+µ- et D0 -> K+π-µ+µ-. En utilisant 2/fb de données collectées par LHCb en 2012, nous mesurons: B(D0 -> K-π+ ρ/ω (->µ+µ-)) = (4.37± 0.12(stat.) ±0.53(syst.)) ×10^-6. C'est la toute première mesure de ce mode. Nous avons également étudié la sensibilité qu'attendra LHCb dans les modes D0 -> h-h’+ µ+µ- pour la mesure de rapport des branchements totaux et partiels, et pour celle d'asymétries, avec les échantillons de données qui seront collectés d'ici 10 ans. Par ailleurs, nous avons déterminé les incertitudes systématiques touchant les recherches de désintégrations à trois corps, D+(s) -> π+µ+µ- et D+(s) -> π-µ+µ+, effectués par LHCb dans les données recueillies en 2011 (1/fb). Enfin, les tests effectués sue les prototypes des cartes d'électronique embarquée qui assureront la lecture des calorimètres de l'expérience le LHCb mise à jour sont présenté dans cette thèse. / Rare charm decays proceed mostly through the c -> u Flavor Changing Neutral Current (FCNC), which is possible only at loop level in the Standard Model (SM). In charmed decays, FCNCs are subject to a very efficient GIM suppression, leading to very rare processes. Consequently, rare charm decays are good tools to probe to New Physics (NP) beyond the SM. NP particles could become detectable by causing observables such as branching ratios and CP or angular asymmetries to deviate from the SM predictions. The main subject of this thesis is the measurement of the branching ratio of the D0 -> K-π+ ρ/ω (->µ+µ-) mode. It will be precious in the future, in particular as a normalization mode in the study of all: D0 -> h-h’+ µ+µ- decays D0 -> K-π+µ+µ-, D0 -> π+π-µ+µ-, D0 -> K+K-µ+µ- and D0 -> K+π-µ+µ-. Using 2/fb of 2012 LHCb data we find: B(D0 -> K-π+ ρ/ω (->µ+µ-)) = (4.37± 0.12(stat.) ±0.53(syst.)) ×10^-6. This is the first measurement of this mode. We also determined sensitivities to total and partial branching fractions and asymmetries in D0 -> h-h’+ µ+µ- decays with future LHCb datasets. In addition, the systematic uncertainties affecting the searches for the 3-body decays, D+(s) -> π+µ+µ- and D+(s) -> π-µ+µ+, carried out by LHCb based on the data collected in 2011 (1/fb). Finally, the results of the tests of front-end electronic board for the Upgrade of LHCb are presented.
60

Chiral description and physical limit of pseudoscalar decay constants with four dynamical quarks and applicability of quasi-Monte Carlo for lattice systems

Ammon, Andreas 10 June 2015 (has links)
In dieser Arbeit werden Massen und Zerfallskonstanten von pseudoskalaren Mesonen, insbes. dem Pion und dem D-s-Meson, im Rahmen der Quantenchromodynamik (QCD) berechnet. Diese Größen wurden im Rahmen der Gitter-QCD, einer gitter-regularisierten Form der QCD, mit vier dynamischen Twisted-Mass Fermionen (Up-, Down-, Strange- und Charm-Quark) berechnet. Dieses Setup bieten den Vorteil der automatischen O(a)-Verbesserung. Der Gitterabstand a wurde mit Hilfe der Pion-Masse und -Zerfallskonstante durch Extrapolation zum physikalischen Punkt, geg. durch das physikal. Verhältnis von f_pi/M_pi, bestimmt. Dabei kamen Formeln aus der chiralen Störungstheorie, die die speziellen Diskretisierungseffekte des Twisted-Mass-Formalismus berücksichtigen, zum Einsatz. Die bestimmten Werte des Gitterabstands, a=0.0899(13) fm (@ beta=1.9), a=0.0812(11) fm (@ beta=1.95) und a = 0.0624(7) fm (@beta=2.1) liegen etwa fünf Prozent über denen vorheriger Bestimmungen (Baron et. al. 2010). Dies erklärt sich vor allem durch eine Untersuchung bezüglich der Anwendbarkeit des Bereiches der Up-/Down-Quark-Massen auf die verwendeten Extrapolationsformeln. Zur Untersuchung des physikalischen Grenzwertes von f_{D_s} werden Formeln der chiralen Störungstheorie für schwere Mesonen (HM-ChiPT) eingesetzt. Das Endergebnis dieser Betrachtung f_{D_s} = 248.9(5.3) MeV liegt etwas über vorherigen Bestimmungen (ETMC 2009, arXiv:0904.095. HPQCD 2010, arXiv:1008.4018) und etwa zwei Standardabweichungen unter dem Mittel aus experimentellen Werten (PDG 2012). Ein weiterer Teil dieser Arbeit behandelt die i.A. schwierige Berechnung von unverbundenen Beiträgen, die z.B. bei der Berechnung der Masse des neutralen Pions eine Rolle spielen. In dieser Arbeit wird eine neue Methode zur Approximation solcher Beiträge vorgestellt, welche auf der sog. Quasi-Monte-Carlo-Methode (QMC-Methode) beruht. Diese Methode birgt große Möglichkeiten zu enormen Einsparungen der Rechenzeit. / This work deals with the determination of decay constants and masses of the pion and D-s meson. This happens in the framework of lattice QCD, a lattice regularised form of QCD. The four dynamical fermions (up, down, strange and charm quark) are described by the twisted-mass approach (TM-QCD) featuring automatic O(a) improvement. The lattice spacing a has been determined using the pion mass and decay constant extrapolated to the physical point, which is determined by the physical ratio f_pi/m_pi. In order to obtain an accurate description, new formulae from Chi-PT, taking into account the special form of discretisation effects of TM-QCD have been employed. The determined results of a = 0.0899(13) fm (@ beta=1.9), a = 0.0812(11)fm (@ beta=1.95) and a = 0.0624(7) fm (@ beta=2.1) are approximately 5% larger than previous determinations (Baron et. al. 2010). This shift is most likely explained by the reduced range of pion masses (

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