Heavy Quark Symmetry Violation in Semileptonic Decays of D Mesons

The decays of $D$ mesons to $K l \nu$ and $K^* l \nu$ final states exhibit significant deviations from the predictions of heavy-quark symmetry, as one might expect since the strange quark's mass is of the same order as the QCD scale. Nonetheless, in order to understand where the most significant effects might lie for heavier systems (such as $B \to D l\nu$ and $B \to D^* l\nu$), the pattern of these deviations is analyzed from the standpoint of perturbative QCD and ${\cal O}(1/m_s)$ corrections. Two main effects are noted. First, the perturbative QCD corrections lead to an overall decrease of predicted rates, which can be understood in terms of production of excited kaonic states. Second, ${\cal O}(1/m_s)$ effects tend to cancel the perturbative QCD corrections in the case of $Kl\nu$ decay, while they have minimal effect in $K^*l\nu$ decay.Comment: 25 pages (LaTeX) + 7 pages of Postscript figures (included at end), EFI-92-3

Avaliação de genótipos de mamoneira no município de Senhor do Bonfim, BA.

Este trabalho teve como objetivo avaliar o desempenho produtivo de dez genótipos de mamoneira no município de Senhor do Bonfim - BA

A Phenomenological Analysis of Non-resonant Charm Meson Decays

We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the $D^+\to \bar{K}^0\pi^+\pi^0$ decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant channels. We analyse how the correct study of this decay will provide a test for the validity of factorization in D meson decays. Finally, we show how form factors could be extracted from non-resonant decays. We particularly discuss about the form factor that can be measured from the $D^+_s\to \pi^-\pi^+\pi^+$ decay. We emphasize on its relevance for the study of the decay $\tau \to \nu_{\tau} 3\pi$ and the extraction of the $a_1$ meson width.Comment: 14 pages, Latex including 6 eps figure

Observações do comprimento e número de frutos do primeiro cacho de três genótipos de mamoneira em Senhor do Bonfim, BA.

Objetivou-se com este trabalho estimar a variabilidade do comprimento do 1o cacho, do número de frutos (bagas) do 1o cacho e da produtividade global das variedades de mamona BRS 149 Nordestina, BRS188 Paraguaçu e SMS Pernambucana na região de Senhor do Bonfim, BA. O experimento foi realizado na Escola Agrotécnica Federal de Senhor do Bonfim ? EAFSB com a participação da Embrapa Semi-Árido, que forneceu as sementes. O delineamento experimental adotado foi em blocos ao acaso, com quatro repetições. Não ocorreu influência significativa dos genótipos nas variáveis comprimento e número de bagas do 1o cacho. Houve correlação entre as variáveis analisadas. As mamonas BRS-149 (Nordestina) e BRS-188 (Paraguaçu) ofereceram valores próximos aos indicados pela EMBRAPA, mas a SMS-Pernambucana ofereceu boa produtividade 63 % superior à indicada pela CONAB.Resumo

Produtividade das cultivares pernambucana, BRS Paraguaçu e BRS Nordestina em Senhor do Bonfim, BA.

Objetivou-se neste trabalho quantificar o total de cachos, o número de sementes e a altura da planta da svariedades BRS Nordestina, BRS Paraguaçu e SMS Pernambucana na região de Senhor do Bonfim, BA

Method for Flavor Tagging in Neutral B Meson Decays

A method is proposed for tagging the flavor of neutral $B$ mesons in the study of CP-violating decay asymmetries. The method makes use of a possible difference in interactions in $B \pi$ or $B^* \pi$ systems with isospins 1/2 and 3/2, and would be particularly clean if the $I = 1/2$ systems can be detected as ``$B^{**}$'' resonances.Comment: Submitted to Phys. Rev. D. 11 pages, LaTeX, Technion-PH-92-40 / PITHA 92/39 / EFI 92-5

On the Dalitz Plot Approach in Non-leptonic Charm Meson Decays

We claim that the non-resonant contribution to non-leptonic charm meson decays may not be constant in the phase space of the reaction. We argue that this can be relevant for any weak reaction. We discuss in detail the decay $D^+ \to K^- \pi^+ \pi^+$.Comment: Version accepted for publication in Physical Review Letters. 9 pages, Latex, including 2 figure

Quantification of aluminium in soil of the Solimões formation, Acre State, Brazil.

The variety of soils in the State of Acre is wide and their chemical profiles are still not fully understood. The nature of the material of origin of these soils is indicated by the high aluminium (Al) content, commonly associated with high calcium (Ca) and magnesium (Mg) contents. The study objective was to use different methods to quantify Al in soils from toposequences formed from material of a sedimentary nature originating from the Solimões Formation, in Acre, Brazil. Trenches were opened at three distinct points in the landscape: shoulder, backslope and footslope positions. Soil samples were collected for physical, chemical, mineralogical analyses. The Al content was quantified using different methods. High Al contents were found in most of these horizons, associated with high Ca and Mg levels, representing the predominant cations in the sum of exchangeable bases. The mineralogy indicates that the soils are still in a low weathering phase, with the presence of significant quantities of 2:1 minerals. Similar Al contents were determined by the methods of NaOH titration, xylenol orange spectrometry and inductively coupled plasma optical emission spectrometry. However, no consistent data were obtained by the pyrocatechol violet method. Extraction with KCl overestimated the exchangeable Al content due to its ability to extract the non-exchangeable Al present in the smectite interlayers. It was observed that high Al contents are related to the instability of the hydroxyl-Al smectite interlayers

Produtividade de milho sob doses e parcelamentos de N em solo com alto teor de matéria orgânica na zona agreste de Sergipe.

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