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Charm studies in emulsionKalinin, Sergey 20 March 2006 (has links)
Neutrino-nucleon scattering is an effective way to investigate the inner structure of the nucleon, to extract the Standard Model parameters and to explore heavy quarks production dynamics. In the last decades, several experiments have been constructed to study weak interactions of neutrinos with nucleons. One of them was CERN-WA95 experiment operated by the CHORUS collaboration. It is based on a hybrid detector with nuclear emulsion as a target followed by electronic devices. Nuclear emulsion provides three dimensional spatial information with an outstanding resolution of the order of one micron. Therefore, it is ideal to detect short-lived particles. A special technique has been developed to reconstruct events in the emulsion which allows to perform a detailed investigation of events such as charmed hadrons production by neutrinos. As a result, the backround in the selected charm sample is up to six times lower compared to similar experiments. Such a method also permits to make direct measurements of some quantities instead of model fittings. This thesis is devoted to the study of the muonic decays of charmed hadrons and their production in emulsion. Manual inspection of charm events gives a complete reconstruction of charm decay topology. The extraction of the inclusive muonic branching ratio is based on the ratios per number of charged daughters in charm decay. Such an approach allows to separetely measure the muonic branching ratios for neutral and charged charm particles. Finally, normalization of the events with a muon in the final state to the charged current events gives dimuon production rate which is found compatible with the previous experiments. On top of that, preliminary results are shown for Bjorken x distribution and for a direct measurement of the Vcd Cabbibo-Kabayashi-Maskawa matrix element.
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Charm studies in emulsionKalinin, Sergey 20 March 2006 (has links)
Neutrino-nucleon scattering is an effective way to investigate the inner structure of the nucleon, to extract the Standard Model parameters and to explore heavy quarks production dynamics. In the last decades, several experiments have been constructed to study weak interactions of neutrinos with nucleons. One of them was CERN-WA95 experiment operated by the CHORUS collaboration. It is based on a hybrid detector with nuclear emulsion as a target followed by electronic devices. Nuclear emulsion provides three dimensional spatial information with an outstanding resolution of the order of one micron. Therefore, it is ideal to detect short-lived particles. A special technique has been developed to reconstruct events in the emulsion which allows to perform a detailed investigation of events such as charmed hadrons production by neutrinos. As a result, the backround in the selected charm sample is up to six times lower compared to similar experiments. Such a method also permits to make direct measurements of some quantities instead of model fittings. This thesis is devoted to the study of the muonic decays of charmed hadrons and their production in emulsion. Manual inspection of charm events gives a complete reconstruction of charm decay topology. The extraction of the inclusive muonic branching ratio is based on the ratios per number of charged daughters in charm decay. Such an approach allows to separetely measure the muonic branching ratios for neutral and charged charm particles. Finally, normalization of the events with a muon in the final state to the charged current events gives dimuon production rate which is found compatible with the previous experiments. On top of that, preliminary results are shown for Bjorken x distribution and for a direct measurement of the Vcd Cabbibo-Kabayashi-Maskawa matrix element.
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CHARM and Strangeness in Quark-Gluon Plasma HadronizationPetran, Michal January 2013 (has links)
This dissertation presents a theoretical study of soft hadron production in relativistic heavy-ion collisions. The aim is to explore the principles governing the hadronization of the expanding quark-gluon plasma (QGP) fireball, and to understand its properties. Strange hadron production and strangeness abundance in the QGP help us to look before the instant of hadronization. Consideration of entropy and charm production further enhances the reach back in time to the first instances of the heavy ion collision. Much of the ongoing effort is to demonstrate the validity of a QGP hadronization model which describes the particle production data accurately and thus allows us to carry out the above research program. We perform a centrality dependent study of multistrange hadrons from Au-Au collisions at √SNN = 62.4 GeV, data obtained at the Relativistic Heavy Ion Collider (RHIC). We show that the statistical hadronization model (SHM) well describes particle production. For all centralities, the particle production conditions are compatible with the earlier proposed critical hadronization pressure suggesting a set of universal hadronization conditions of QGP. Heavy-ion collisions at the Large Hadron Collider (LHC) present a new challenge for SHM in describing particle production at TeV energy scales. The chemical non-equilibrium model gives a good description of the hadron production in Pb-Pb collisions at √SNN = 2.76 TeV consistently as a function of centrality. Moreover, the model parameters, such as chemical freeze-out temperature, assume expected values suggested by results from previous studies at lower energies. The quark-gluon plasma fireball hadronizes at the same universal hadronization conditions, that is a common critical pressure, entropy and energy density. At LHC energies, a significant amount of charm is expected to be produced. It is therefore crucial to incorporate charm into the present description of particle production. We present a new tool, an upgraded SHARE with CHARM program, that quantifies the effect of charm on the yield of lighter hadrons and physical properties of the hadronizing fireball. In addition to light flavors (u,d,s), SHARE with CHARM describes charm hadron production and decays of charm hadrons. According to present experimental results, charm decays mainly affect the yields of multistrange particles. This dissertation begins with an introduction to the particle production in heavy-ion collisions and SHM framework, followed by a summary of results that are either published or submitted to peer-reviewed journals and others which are published as conference proceedings. Reprints of the publications are attached to the dissertation as appendices. Each appendix is prefaced with a short summary of presented results, and my contribution to these works is described.
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Weak decays of charmed particlesTurcotte, Marc Gilles. January 1986 (has links)
No description available.
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Measurement of the D*+/- cross-section at HERMESVolk, Erik. January 2001 (has links)
Heidelberg, Univ., Diss., 2001.
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Untersuchung der Produktion charmhaltiger Mesonen in der Photon-Photon-Streuung mit dem OPAL-ExperimentPatt, Jochen. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2000--Freiburg.
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Measurement of the mixing parameters of neutral charm mesons and search for indirect CP violation with D⁰ → K⁰_sπ⁺π⁻ decays at LHCbReichert, Stefanie January 2016 (has links)
The hadronic decay D0 → KS pi+ pi- provides direct access to the measurement of the mixing parameters of the neutral charm meson system and allows to test for indirect CP violation. Mixing is a time-dependent phenomenon for which the time evolution of the transition amplitude of a D0 (anti-D0) decay to the final state KS pi+ pi- has to be considered. The parameters driving those time-dependent oscillations are x and y, depending on the masses and widths of the physical eigenstates. The CP violation parameters |q/p| and phi describe the superposition of the flavour eigenstates D0 and anti-D0 and of the physical eigenstates D1 and D2. By measuring the time- and phase-space dependent distribution of D0 → KS pi+ pi- decays, the mixing parameters can be extracted and a search for indirect CP violation can be performed. This thesis reports a measurement of the mixing parameters and the preparations of a measurement of the CP violation parameters on data collected with the LHCb experiment in 2011 and 2012, corresponding to an integrated luminosity of 3/fb. The D0 and anti-D0 mesons are required to originate from a semileptonic decay of a B meson. The parameters of interest are extracted from a fit in D0 decay time and the Dalitz variables. The phase-space distribution of D0 → KS pi+ pi- decays is modelled by expressing the three-body decay as a succession of two-body decays. The decay amplitude of a D0 or anti-D0 meson into KS pi+ pi- final state is a superposition of all possible intermediate resonances and the single resonances interfere with each other across the phase-space.
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Weak decays of charmed particlesTurcotte, Marc Gilles. January 1986 (has links)
No description available.
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[pt] ESTRATÉGIAS PARA A BUSCA DE VIOLAÇÃO DE CARGA-PARIDADE NO CANAL D+ → PI−PI+PI+ NO EXPERIMENTO LHCB / [en] STRATEGIES FOR THE SEARCH OF CHARGE-PARITY VIOLATION IN THE D+ → PI−PI+PI+ DECAY IN THE LHCB EXPERIMENTLUCAS CORDEIRO ROMAO 16 January 2023 (has links)
[pt] A partir do século passado descobrimos a existência de antipartículas e,
desde então, a busca por entender a assimetria entre partícula e antipartículas
tem sido um forte campo de pesquisa na física. Dentre as condições que
possibilitam a assimetria matéria-antimatéria no Universo, está o fenômeno da
Violação de Carga-Paridade (VCP). Devido à ela observamos diferenças entre
os processos decaimento de uma partícula e sua antipartícula. Tal fenômeno
tem efeitos importantes para mésons formados pelos quarks b ou s, porém
as predições deste efeito para o setor de charme são muito pequenas, com
assimetrias de CP em torno da ordem de 10−3 ou menores. De fato, apenas
recentemente a VCP foi observada em decaimentos de 2 corpos de mésons D0.
Esta dissertação discute duas estratégias na busca por VCP no canal
D+ → π−π+π+ utilizando dados do experimento LHCb durante o Run II.
O método de busca por VCP, método Mirandizing, consiste em computar
estatisticamente as populações de D+ e D− em intervalos do espaço de fase
bidimensional, calculando a significância da diferença dessas populações. Para
amostras de grande estatística, como é o nosso caso, o objetivo final é aplicar
um método alternativo que consiste em obter o número das populações através
de ajustes de massa para cada intervalo.
Este trabalho tem como objetivo realizar a validação do método. Nossa
estratégia é realizar os procedimentos dividindo a amostra de forma aleatória
em duas sub-amostras e não separando nas amostras de D+ e D−. O que se
espera, então, são resultados que demonstrem compatibilidade estatística entre
as duas amostras. Além dessa validação utilizando os dados, vamos, também,
realizar o mesmo procedimento em 100 pseudo-experimentos. Adicionalmente,
realizamos os estudos de sensibilidade a fim de verificar em quais possíveis
cenários a VCP poderia ser observada nesse canal, dado o tamanho da
amostra total. Para este estudo, obteremos o número das populações através
da contagem direta (método Mirandizing) dos eventos do espaço de fase dentro
da região de massa de maior com maior concentração de eventos de sinal. / [en] Last century we discovered the existence of antiparticles, and since then
the search to understand the asymmetry between particles and antiparticles
has been a strong field of research in physics. Among the conditions that make
matter-antimatter asymmetry possible in the Universe is the Charge-Parity
Violation (CPV) phenomenon. Due to it we observe differences between the
decay processes of a particle and its antiparticle. Such a phenomenon has
important effects for mesons formed by b or s quarks, but the predictions of
this effect for the charm sector are very small, with CP asymmetries around
the order of 10−3 or smaller. In fact only recently has CPV been observed in
2-body decays of D0 mesons.
This dissertation presents the validation of strategies in the search for
CPV in the D+ → π−π+π+ channel using data from the LHCb experiment
during Run II. The CPV search method, the so-called Mirandizing method,
consists of statistically computing the populations of D+ and D− in intervals of
the two-dimensional phase space, obtaining the significance of the difference of
these populations. For large statistical samples, as is our case, the ultimate goal
is to apply an alternative method by obtaining the number of the populations
through mass fits for each interval.
This work aims to perform the validation of the method. Our strategy is
to perform the procedure by dividing the sample randomly into two subsamples,
but not separating into the D+ and D− samples. What is expected, then,
is that the results demonstrate statistical compatibility between the two samples.
In addition to this validation using data, we will also perform the same
procedure on 100 pseudo-experiments. Finally, we perform sensitivity studies
in order to verify the possible scenarios in which CPV could be observed in this
channel, given the total sample size. For this study, we will obtain the number
of the populations by directly counting the phase space events (Mirandizing)
within the mass region with the highest concentration of signal events.
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Experimental Study of Three-body Cabibbo-suppressed D<sup>0</sup> Decays and Extraction of <i>CP</i> Violation ParametersMishra, Kalanand Mishra 22 April 2008 (has links)
No description available.
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