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Estudo do impacto do empilhamento em eventos na difração simples dura no CMS/LHC / Study on the pile-up impact in the variables commonly used to identify hard single diffractive eventsEliza Melo da Costa 22 December 2009 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Apresenta-se neste trabalho um estudo sobre o impacto do empilhamento de eventos (pile-up), nas distribuições das variáveis comumente utilizadas para identificar eventos difrativos, na topologia de difração dura simples produzindo dijatos, nas condições do CMS para baixa luminosidade (2 x 1033 cm -2 s-1). O cenário de baixa luminosidade citado acima equivale aproximadamente a 5 eventos de pile-up em média por cruzamento de pacotes. Para simular o sinal, difrativos (com e sem pile-up), usamos o gerador POMWIG (1). Para os eventos não-difrativos (com e sem pile-up), utilizamos o gerador PYTHIA (2),bem como para a produção dos eventos de pile-up (eventos simulados utilizando eventos
de minimum bias). / We present here a study on the pile-up impact in the variables commonly used to identify diffractive events, the topology of single diffraction producing hard jets in the CMS conditions for low luminosity (2 X 1033 cm -2 s-1). The low luminosity scenario mentioned above is equivalent to approximately 5 pile-up events on average by crossing packages. To simulate the signal, diffractive events (with and without pile-up), we use the generator POMWIG(1). For the non-diffractive events (with and without pile-up), we use generator PYTHIA(2), and for the production of events of pile-up as well (events simulated using minimum bias events).
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Estudo dos processos de dijatos exclusivos a √s = 7 TeV no CMS/LHC / Exclusivity dijets production at √s = 7 TeV on CMS/LHCEliza Melo da Costa 24 May 2013 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Este trabalho apresenta um estudo sobre a produção de dijatos exclusivos em interações pp, do tipo pp → p "+" dijatos "+" p, onde os prótons desta interação permanecem intactos, e o símbolo "+" indica uma lacuna na pseudorapidez, uma região com ausência de atividade hadrônica entre os prótons espalhados e o sistema central de dijatos; este processo é conhecido como produção central exclusiva. A análise utiliza uma amostra de dados que corresponde a uma luminosidade efetiva de 24;48 pb-1 coletados pelo experimento Compact Muon Solenoid (CMS) no Large Hadron Collider (LHC), no ano de 2010, com energia de centro de massa √s = 7 TeV. Este canal possui uma assinatura experimental única, caracterizada pelos prótons espalhados na região frontal, ou a baixos ângulos e duas grandes lacunas opostas. O processo da produção central exclusiva é útil para o entendimento das interações no contexto da QCD. / This work presents a study about the exclusive dijets production in pp interactions of type pp → p "+" dijets "+" p, where the protons this interaction remain intact, and the symbol "+" denotes a gap in pseudorapidity, a region with no hadronic activity between the scattered protons and the central dijets system, this process is known as central exclusive production. The analysis uses a data sample corresponding to effective luminosity of 24:48 pb -1 collected by the experiment Compact Muon Solenoid (CMS) at Large Hadron Collider (LHC), in 2010, with center of mass energy of √s = 7 TeV. This channel has a experimental signature unique, characterized by scattered protons in the frontal region or low angles and two large gaps opposite. The central exclusive production process is useful for understanding the interactions in the context of QCD.
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Estudo do impacto do empilhamento em eventos na difração simples dura no CMS/LHC / Study on the pile-up impact in the variables commonly used to identify hard single diffractive eventsEliza Melo da Costa 22 December 2009 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Apresenta-se neste trabalho um estudo sobre o impacto do empilhamento de eventos (pile-up), nas distribuições das variáveis comumente utilizadas para identificar eventos difrativos, na topologia de difração dura simples produzindo dijatos, nas condições do CMS para baixa luminosidade (2 x 1033 cm -2 s-1). O cenário de baixa luminosidade citado acima equivale aproximadamente a 5 eventos de pile-up em média por cruzamento de pacotes. Para simular o sinal, difrativos (com e sem pile-up), usamos o gerador POMWIG (1). Para os eventos não-difrativos (com e sem pile-up), utilizamos o gerador PYTHIA (2),bem como para a produção dos eventos de pile-up (eventos simulados utilizando eventos
de minimum bias). / We present here a study on the pile-up impact in the variables commonly used to identify diffractive events, the topology of single diffraction producing hard jets in the CMS conditions for low luminosity (2 X 1033 cm -2 s-1). The low luminosity scenario mentioned above is equivalent to approximately 5 pile-up events on average by crossing packages. To simulate the signal, diffractive events (with and without pile-up), we use the generator POMWIG(1). For the non-diffractive events (with and without pile-up), we use generator PYTHIA(2), and for the production of events of pile-up as well (events simulated using minimum bias events).
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Estudo dos processos de dijatos exclusivos a √s = 7 TeV no CMS/LHC / Exclusivity dijets production at √s = 7 TeV on CMS/LHCEliza Melo da Costa 24 May 2013 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Este trabalho apresenta um estudo sobre a produção de dijatos exclusivos em interações pp, do tipo pp → p "+" dijatos "+" p, onde os prótons desta interação permanecem intactos, e o símbolo "+" indica uma lacuna na pseudorapidez, uma região com ausência de atividade hadrônica entre os prótons espalhados e o sistema central de dijatos; este processo é conhecido como produção central exclusiva. A análise utiliza uma amostra de dados que corresponde a uma luminosidade efetiva de 24;48 pb-1 coletados pelo experimento Compact Muon Solenoid (CMS) no Large Hadron Collider (LHC), no ano de 2010, com energia de centro de massa √s = 7 TeV. Este canal possui uma assinatura experimental única, caracterizada pelos prótons espalhados na região frontal, ou a baixos ângulos e duas grandes lacunas opostas. O processo da produção central exclusiva é útil para o entendimento das interações no contexto da QCD. / This work presents a study about the exclusive dijets production in pp interactions of type pp → p "+" dijets "+" p, where the protons this interaction remain intact, and the symbol "+" denotes a gap in pseudorapidity, a region with no hadronic activity between the scattered protons and the central dijets system, this process is known as central exclusive production. The analysis uses a data sample corresponding to effective luminosity of 24:48 pb -1 collected by the experiment Compact Muon Solenoid (CMS) at Large Hadron Collider (LHC), in 2010, with center of mass energy of √s = 7 TeV. This channel has a experimental signature unique, characterized by scattered protons in the frontal region or low angles and two large gaps opposite. The central exclusive production process is useful for understanding the interactions in the context of QCD.
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Reactivation of fractures as discrete shear zones from fluid enhanced reaction softening, Harquahala metamorphic core complex, west-central ArizonaPollard, Brittney Maryah 04 September 2014 (has links)
Discrete (mm- to m-scale) mylonitic shear zones in the northeastern Harquahala metamorphic core complex, Arizona, show evidence of fluid-mineral interactions catalyzing deformation and metamorphism. Many contain a deformed central epidote vein with adjacent bleached haloes and flanking paired shear zones that indicate significant fluid-rock interaction during deformation. An integration of structural and geochemical methods was employed to understand timing, metamorphic conditions, and physiochemical processes responsible for producing the discrete shear zones. Field and microstructural evidence suggest the zones initiated on antecedent fractures. Electron backscatter diffraction (EBSD) analyses show a significant coaxial contribution to the shear, and quartz deformation predominately by prism <a> slip, along with some rhomb <a> slip, suggesting amphibolite-facies conditions during shearing. Fourier Transform Infrared spectroscopy analyses of quartz reveal higher water contents within shear zones than within country rocks, indicating fluid infiltration synchronous with shearing. Stable isotope analyses of quartz and feldspar from mylonites are consistent with an igneous or metamorphic fluid origin. Microstructural observations suggest that the zone morphology with epidote veins, bleached haloes, and flanking discrete paired shear zones was developed predominantly from reaction softening mechanisms. The increase in deformation from bleached rock to flanking shear zones is marked by progressive modal increases in biotite and myrmekite, and modal decreases in K-feldspar, and locally epidote and titanite. Myrmekitic textures recrystallized readily and resulted in progressively greater grain size reduction of feldspar, which aided in the progressive alignment and linkage of the biotite grains, which together concentrated the deformation in bands. Volume reduction resulting from some of the metamorphic reactions may have led to a positive feedback cycle among fluid infiltration, metamorphism and deformation. U-Pb isotope analyses of syn-metamorphic titanite yield an age of ~70 Ma, suggesting the shear zones formed during cooling of the Late Cretaceous (75.5±1.3 Ma) Brown’s Canyon pluton, consistent with their top-to-the-southwest sense of shear, rather than during top-to-the-northeast directed Miocene metamorphic core complex exhumation. Petrography, EBSD analyses, and U-Pb dating of titanite from other (non-discrete) mylonites in the area imply most formed synchronously with the discrete shear zone mylonites. Only rare, scattered mylonites show features consistent with metamorphic core complex exhumation. / text
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