114 research outputs found

    New Physics and Evidence for a Complex CKM

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    We carefully analyse the present experimental evidence for a complex CKM matrix, even allowing for New Physics contributions to Ï”K\epsilon_{K}, aJ/ΚKSa_{J/\Psi K_S}, ΔMBd\Delta M_{B_{d}}, ΔMBs\Delta M_{B_{s}}, and the ΔI=1/2\Delta I=1/2 piece of B→ρρB\to\rho\rho and B→ρπB\to\rho\pi. We emphasize the crucial r\^ ole played by the angle Îł\gamma in both providing irrefutable evidence for a complex CKM matrix and placing constraints on the size of NP contributions. It is shown that even if one allows for New Physics a real CKM matrix is excluded at a 99.92% C.L., and the probability for the phase Îł\gamma to be in the interval [−170∘;−10∘]âˆȘ[10∘;170∘][-170^\circ;-10^\circ]\cup [10^\circ;170^\circ] is 99.7%.Comment: 24 pages, 15 figures. Revised version, analyses extended to more general New Physics; C.L. of exclusion of a real CKM matrix include

    Efeito da adição de sulfato de amÎnio sobre a produção de åcido succínico durante a fermentação alcoólica

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    Succinic acid production by yeasts during alcoholic fermentation of cane molasse supplemented with 25, 50 and 100 ppm of nitrogen in the form of ammonium sulfate was determined by gas-liquid chromatography. Ethanol production was not effected by the different levels of nitrogen, but there was a significant reduction in the content of succinic acid which was inversely related with the ammonium sulfate concentration in the medium.A produção de ĂĄcido succĂ­nico por leveduras durante a fermentação alcoĂłlica de mosto de melaço suplementado com 25, 50 e 100 ppm de nitrogĂȘnio na forma de sulfato de amĂŽnio foi determinada por cromatografia em fase gasosa. A adição de nitrogĂȘnio amoniacal nĂŁo afetou significativamente a produção de ĂĄlcool etĂ­lico. Houve redução significativa no teor de ĂĄcido succĂ­nico com o aumento da quantidade de nitrogĂȘnio adicionada

    Measurement of the View the tt production cross-section using eÎŒ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σttÂŻ) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σttÂŻ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σttÂŻ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented
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