Probing New Physics using top quark polarization in the e+e- -> t \bar{t} process at future Linear Colliders

We investigate the sensitivity to new physics of the process e+e- -> t bar{t} when the top polarization is analyzed using leptonic final states e+e- -> t \bar{t} -> l+l- b \bar{b} nu_l \bar{nu}_l. We first show that the kinematical reconstruction of the complete kinematics is experimentally tractable for this process. Then we apply the matrix element method to study the sensitivity to the Vt\bar{t} coupling (V being a vector gauge boson), at the tree level and in the narrow width approximation. Assuming the ILC baseline configuration, sqrt{S}=500 GeV, and a luminosity of 500 fb^{-1}, we conclude that this optimal analysis allows to determine simultaneously the ten form factors that parameterize the Vt\bar{t} coupling, below the percent level. We also discuss the effects of the next leading order (NLO) electroweak corrections using the GRACE program with polarized beams. It is found that the NLO corrections to different beam polarization lead to significantly different patterns of contributions.Comment: 14 pages, 4 figures, Proceedings for the TYL-FJPPL workshops on "Top Physics at ILC

Estudo observacional dos critérios desejados para obter a qualidade de moldes definitivos utilizados em prótese fixa

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.A moldagem consiste no ato de copiar as características anatômicas da cavidade bucal com o uso de diferentes materiais de moldagem dispensados em moldeiras de estoque ou individuais. Algumas características desses materiais afetam a precisão e estabilidade dimensional do molde, sendo que este ainda pode ser afetado pela manipulação do material, desinfecção ou técnica de moldagem. Este estudo observou os critérios desejados para obter a qualidade de moldes definitivos. Foram fotografados 48 moldes para próteses fixas, antes do vazamento, em dois laboratórios comerciais de Florianópolis. As fotografias dos moldes foram analisadas por dois observadores calibrados que responderam a um questionário. Dos 48 moldes analisados, verificou-se que 45,84% foram confeccionados com silicone de adição, 52,08% com silicone de condensação e 2,08% com poliéter. Quanto ao tamanho do molde, houve mais moldes parciais (54,16%) que totais (45,83%). Na observação da manipulação e distribuição do material na moldeira, 83,34% foi considerada adequada. Quando foi observada a visibilidade das áreas preparadas no molde, encontrou-se que as paredes axiais e oclusal/incisal foram visualizadas em 91,6% dos moldes e a área de afastamento gengival e a linha do término do preparo em 33,3% dos moldes. Apenas 29,17% dos moldes não apresentaram nenhum defeito. Os defeitos encontrados em 74,5% dos moldes foram: bolhas negativas (71,42%), bolhas positivas (25,71%), rasgamentos (14,28%) e enrugamentos (5,71%), associados na mesma amostra ou não. Por meio do teste estatístico Chi-quadrado, obteve-se associações entre as variáveis estudadas. Todos os moldes classificados como adequados para o vazamento (30%) permitiram a visualização das paredes e do término do preparo. Apenas 2% dos moldes apresentaram restos de cimento e 19% apresentaram defeitos. A maioria dos moldes classificados como inadequados (70%) permitiu a visualização das paredes do preparo (62%), porém, em apenas 2% desses moldes, o término do preparo foi visualizado (p˂0,05). Desta forma, concluiu-se que o fato de não haver um afastamento gengival adequado e, consequentemente, uma cópia efetiva da área do término cervical, é o principal fator que compromete a qualidade do molde, indicando sua repetição.Impression is the act of copying the anatomical characteristics of the oral cavity with the use of different materials dispensed into individual or stock trays. Some aspects of these materials affect the accuracy and dimensional stability of the impression, and this may still be affected by the manipulation of the impression material, disinfection or impression technique. This study observed the desired criteria to achieve quality in the final impression. Forty-eight molds for fixed prostheses were photographed before pouring, in two commercial laboratories of Florianópolis. The photos of the impression were analyzed by two calibrated observers who responded to a questionnaire. Of the 48 analyzed impressions, it was found that 45,84% were prepared with addition silicones, 52,08% with condensation silicones and 2.08% with polyether. Regarding the size of the molds, there were more partial molds (54,16%), than total molds (45,83%). In the observation of the manipulation and distribution of the material in the tray, 83,34% of the cases were considered adequate. When the visibility of the prepared areas of the impression was observed, it was found that the axial and occlusal/incisal prepared walls were visualized in 91,6% of the impression areas and that the gingival retraction line and the end of the preparation in 33,3% of the molds. Only 29,17% of the molds presented no defect. The defects found in 74,5% of the molds were: negative bubbles (71,42%), positive bubbles (25,71%), rupture (14,28%) and wrinkles (5,71%), associated in the same sample or not. Through the Chi-square statistic test, associations between variables were obtained. All molds classified as suitable for pouring (30%) allowed the visualization of the prepared walls and of the end of the preparation. Only 2% of the impressions presented remains of dental cement and 19% had defects. Most impressions classified as inappropriate (70%) allowed the visualization of the prepared walls of the preparation (62%), but in only 2% of these molds the end of the preparation was visualized (p˂0,05). Thus, it was concluded that the absence of an adequate gingival retraction and, consequently, an effective copy of the cervical end area, is the main factor that affects the quality of the impression, indicating its repetition

Generic User Process Interface for Event Generators

Generic Fortran common blocks are presented for use by High Energy Physics event generators for the transfer of event configurations from parton level generators to showering and hadronization event generators.Comment: Physics at TeV Colliders II Workshop, Les Houches, France, May 2001 14 pages, 6 figure

Hysteresis of Backflow Imprinted in Collimated Jets

We report two different types of backflow from jets by performing 2D special relativistic hydrodynamical simulations. One is anti-parallel and quasi-straight to the main jet (quasi-straight backflow), and the other is bent path of the backflow (bent backflow). We find that the former appears when the head advance speed is comparable to or higher than the local sound speed at the hotspot while the latter appears when the head advance speed is slower than the sound speed bat the hotspot. Bent backflow collides with the unshocked jet and laterally squeezes the jet. At the same time, a pair of new oblique shocks are formed at the tip of the jet and new bent fast backflows are generated via these oblique shocks. The hysteresis of backflow collisions is thus imprinted in the jet as a node and anti-node structure. This process also promotes broadening of the jet cross sectional area and it also causes a decrease in the head advance velocity. This hydrodynamic process may be tested by observations of compact young jets.Comment: 9 pages, 5 figures, accepted for publication in ApJ