183,646 research outputs found

    Measuring |V_{td} / V_{ub}| through B -> M \nu \bar\nu (M=\pi,K,\rho,K^*) decays

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    We propose a new method for precise determination of |V_{td} / V_{ub}| from the ratios of branching ratios BR(B -> \rho \nu \bar \nu ) / BR(B ->\rho l \nu ) and BR(B -> \pi \nu \bar \nu ) / BR(B -> \pi l \nu ). These ratios depend only on the ratio of the Cabibbo-Kobayashi-Maskawa (CKM) elements |V_{td} / V_{ub}|$ with little theoretical uncertainty, when very small isospin breaking effects are neglected. As is well known, |V_{td} / V_{ub}| equals to (\sin \gamma) / (\sin \beta) for the CKM version of CP-violation within the Standard Model. We also give in detail analytical and numerical results on the differential decay width d\Gamma(B -> K^* \nu \bar \nu ) / dq^2 and the ratio of the differential rates dBR(B -> \rho \nu \bar \nu )/dq^2 / dBR(B -> K^* \nu \bar \nu )/dq^2 as well as BR(B -> \rho \nu \bar \nu ) / BR(B -> K^* \nu \bar \nu) and BR(B -> \pi \nu \bar \nu ) / BR(B -> K \nu \bar \nu).Comment: LaTeX with 2 figures, 12 page

    A note on q-Bernstein polynomials

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    In this paper we constructed new q-extension of Bernstein polynomials. Fron those q-Berstein polynomials, we give some interesting properties and we investigate some applications related this q-Bernstein polynomials.Comment: 13 page

    User's guide for the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) CELL-ALL tape

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    The SMMR instrument onboard the Nimbus-7 satellite has been in operation since October 1978. It provided global coverage of passive microwave observations at 6.6, 10.7, 18, 21, and 37 GHz. The oberved brightness temperature can be used to retrieve geophysical parameters, principally sea surface temperature, atmospheric water vapor and liquid water content over oceans, sea ice concentration, and snow cover over land. The SMME CELL-ALL Tape contains earth-located calibrated brightness temperature data which have been appropriately binned into cells of various grid sizes, allowing intercomparisons of observations made at different frequencies (with corresponding different footprint sizes). This user's guide describes the operation of the instrument, the flow of the data processing the calibration procedure, and the characteristics of the calibrated brightness temperatures and how they are binned. Detailed tape specifications and lists of available data are also provided

    Low scale Seesaw model and Lepton Flavor Violating Rare B Decays

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    We study lepton flavor number violating rare B decays, b→slh±ll∓b \to s l_h^{\pm} l_l^{\mp}, in a seesaw model with low scale singlet Majorana neutrinos motivated by the resonant leptogenesis scenario. The branching ratios of inclusive decays b→slh±llˉ∓ b \to s l_h^{\pm} \bar{l_l}^{\mp} with two almost degenerate singlet neutrinos at TeV scale are investigated in detail. We find that there exists a class of seesaw model in which the branching fractions of b→sτμ b \to s \tau \mu and τ→μγ\tau \to \mu \gamma can be as large as 10−1010^{-10} and 10−910^{-9} within the reach of Super B factories, respectively, without being in conflict with neutrino mixings and mass squared difference of neutrinos from neutrino data, invisible decay width of ZZ and the present limit of Br(μ→eγ)Br(\mu \to e \gamma).Comment: 19 pages, 6 figure
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