30 research outputs found

    Measuring the Photon Helicity in Radiative B Decays

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    We propose a way of measuring the photon polarization in radiative B decays into K resonance states decaying to K\pi\pi, which can test the Standard Model and probe new physics. The photon polarization is shown to be measured by the up-down asymmetry of the photon direction relative to the K\pi\pi decay plane in the K resonance rest frame. The integrated asymmetry in K_1(1400)\to K\pi\pi, calculated to be 0.34\pm 0.05 in the Standard Model, is measurable at currently operating B factories.Comment: 4 pages, final version to appear in Physical Review Letter

    What Have We Learned from RHIC?

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    In this talk, I present what I believe we have learned from the recent RHIC heavy ion experiments. The goal of these experiments is to make and study matter at very high energy densities, greater than an order of magnitude larger than that of nuclear matter. Have we made such matter? What have we learned about the properties of this matter? What do we hope and expect to learn in the future?Comment: 34 figure

    Exclusive semileptonic B decays to radially excited D mesons

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    Exclusive semileptonic B decays to radially excited charmed mesons are investigated at the first order of the heavy quark expansion. The arising leading and subleading Isgur-Wise functions are calculated in the framework of the relativistic quark model. It is found that the 1/m_Q corrections play an important role and substantially modify results. An interesting interplay between different corrections is found. As a result the branching ratio for the B-> D'e\nu decay is essentially increased by 1/m_Q corrections, while the one for B-> D*'e\nu is only slightly influenced by them.Comment: 19 pages, revtex, 6 figures, uses rotating.st

    Universal Behavior of Charged Particle Production in Heavy Ion Collisions

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    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.Comment: 4 Pages, 5 Figures, contributed to the Proceedings of Quark Matter 2002, Nantes, France, 18-24 July 200

    Production and Decay of Scalar Stoponium Bound States

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    In this paper we discuss possible signatures for the production of scalar \stst\ (stoponium) bound states \sigst\ at hadron colliders, where \st\ is the lighter scalar top eigenstate. We first study the decay of \sigst; explicit expressions are given for all potentially important decay modes. If \st\ has unsuppressed two--body decays, they will always overwhelm the annihilation decays of \sigst. Among the latter, we find that usually either the gggg or hhhh final state dominates, depending on the size of the off--diagonal entry of the stop mass matrix; hh is the lighter neutral scalar Higgs boson of the minimal supersymmetric model. If \msig\ happens to be close to the mass of one of the neutral scalar Higgs bosons, QQˉQ \bar{Q} final states dominate (Q=bQ=b or tt). \ww\ and ZZZZ final states are subdominant. We argue that \sigst \rightarrow \gamgam decays offer the best signal for stoponium production at hadron colliders. The tevatron should be able to close the light stop window left open by LEP searches, but its mass reach is limited to \msig \leq 90 GeV. In contrast, at the LHC one should ultimately be able to probe the region \msig \leq 700 GeV, if the hhhh partial width is not too large. We also comment on the feasibility of searching for \sigst\ production at hadron colliders in the ZZ, ZγZZ, \ Z \gamma and \fourtau\ final states, and briefly mention \sigst\ production at \gamgam\ colliders.Comment: 31 pages plus 10 figures (available from DREES@WISCPHEN); LaTeX with equation.sty; MAD/PH/808, KEK-TH-37

    Quality of life in people with chronic hemodialysis: association with sociodemographic, medical-clinical and laboratory variables Calidad de vida de personas en hemodiálisis crónica: relación con variables sociodemográficas, médico-clínicas y de laboratorio Qualidade de vida de pessoas em hemodiálise crônica: relação com variáveis sociodemográficas, médico-clínicas e de laboratório

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    AIM: determine the quality of life for people in chronic hemodialysis and its association with sociodemographic, medical-clinical and laboratory variables. METHOD: exploratory, descriptive, cross-sectional study with stratified probability sampling. Quality of life was assessed using the KDQOL-36TM. Data were analyzed using SPSS statistical software. RESULTS: 354 people in chronic hemodialysis had low scores on most dimensions of quality of life, mainly Burden of Disease, Physical and Mental Component. Age, sex, education, income, time on dialysis, etiology of the disease, smoking, hospitalizations, albumin, creatinine and transplants were related. The results reveal multiple factors related to quality of life. CONCLUSION: there is a need to research on other aspects that permit focusing and optimizing the nursing care for these people.<br>OBJETIVO: determinar la calidad de vida de personas en hemodiálisis crónica y su relación con variables sociodemográficas, médico-clínicas y de laboratorio. MÉTODO: estudio exploratorio, descriptivo, transaccional con muestreo probabilístico estratificado. Calidad de vida fue evaluada mediante el instrumento KDQOL-36TM. Los datos fueron analizados con el programa estadístico SPSS. RESULTADOS: 354 personas en hemodiálisis crónica presentaron puntuaciones bajas en la mayoría de las dimensiones de calidad de vida, principalmente Carga de la Enfermedad, Componente Físico y Mental. Edad, sexo, escolaridad, ingresos económicos, tiempo en diálisis, etiología de la enfermedad, cigarrillo, hospitalizaciones, número medicamentos, albúmina, creatinina, trasplantes resultaron relacionados. Los resultados revelan múltiples factores relacionados con la calidad de vida. CONCLUSIÓN: existe necesidad de investigar otros aspectos que permitan enfocar y optimizar el cuidado de enfermería dirigido a estas personas.<br>OBJETIVO: determinar a qualidade de vida de pessoas em hemodiálise crônica e sua relação com variáveis sociodemográficas, médico-clínicas e de laboratório. MÉTODO: estudo exploratório, descritivo, transacional com amostragem de probabilidade estratificada. Qualidade de vida foi avaliada mediante o instrumento KDQOL-36TM. Os dados foram analisados com o programa estatístico SPSS. RESULTADOS: 354 pessoas em hemodiálise crônica apresentaram pontuações baixas na maioria das dimensões de qualidade de vida, principalmente carga da doença, componente físico e mental. Foram encontradas associações com idade, sexo, escolaridade, renda, tempo em diálise, etiologia da doença, cigarro, hospitalizações, quantidade de remédios, albumina, creatina e transplantes. Os resultados revelam múltiplos fatores relacionados à qualidade de vida. CONCLUSÃO: existe a necessidade de se investigar outros aspectos que permitam enfocar e otimizar o cuidado da enfermagem dirigido a essas pessoas
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