1,725 research outputs found

    Two-loop QCD corrections to semileptonic b decays at maximal recoil

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    We present a complete O(αs2)O(\alpha_s^2) correction to the differential width of the inclusive semileptonic decay b→clνlb\to cl\nu_l at the kinematical point of vanishing invariant mass of the leptons, q2=0q^2=0. Together with the recently computed O(αs2)O(\alpha_s^2) correction at the upper boundary of the lepton invariant mass spectrum, this new information permits an estimate of the O(αs2)O(\alpha_s^2) effect in the total inclusive semileptonic decay width b→clνlb\to cl\nu_l. We argue that the non-BLM part of the O(αs2)O(\alpha_s^2) correction gives at most 1% correction to the inclusive semileptonic decay width b→clνlb\to cl\nu_l. This significantly improves the credibility of extracting ∣Vcb∣|V_{cb}| from the inclusive semileptonic decays of the b-hadrons.Comment: 8 pages, revte

    Techniques for computing two-loop QCD corrections to b-->c transitions

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    We have recently presented the complete O(alpha_s^2) corrections to the semileptonic decay width of the b quark at maximal recoil. Here we discuss various technical aspects of that calculation and further applications of similar methods. In particular, we describe an expansion which facilitates the phase space integrations and the treatment of the mixed real-virtual corrections, for which Taylor expansion does not work and the so-called eikonal expansion must be employed. Several terms of the expansion are given for the O(alpha_s^2) QCD corrections to the differential semileptonic decay width of the b --quark at maximal recoil. We also demonstrate how the light quark loop corrections to the top quark decay rate can be obtained using the same methods. We briefly discuss the application of these techniques to the calculation of the O(alpha_s^2) correction to zero recoil sum rules for heavy flavor transitions.Comment: 22 pages, revte

    Polarized Moller Scattering Asymmetries

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    The utility of polarized electron beams for precision electroweak studies is described. Parity violating Moller scattering asymmetries in e-e- --> e-e- are discussed. Effects of electroweak radiative corrections and the running sin^2(theta_W(Q^2)) are reviewed. The sensitivity of E158 (a fixed target e-e- experiment at SLAC) and future e-e- collider studies to ``new physics'' is briefly outlined.Comment: Updated Fig.

    Pressure drags due to two-dimensional fabrication-type surface roughness on an ogive cylinder at transonic speeds

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    Pressure drags due to two-dimensional fabrication- type surface roughness on ogive cylinder at transonic speed

    Electroweak corrections to decays involving a charged Higgs boson

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    We present complete one-loop radiative corrections to the decay rate of a top quark into a charged Higgs boson and a bottom quark, and for the decay of a charged Higgs boson into leptons. The results are discussed in the framework of the two Higgs boson extension of the Standard Model suggested by supersymmetry. The effect of electroweak corrections after exclusion of universal corrections Δr\Delta r is found to decrease the partial width of the top quark typically by 5%.Comment: 16 pages plus 11 figures available from the author upon request, latex, Alberta Thy-29-9
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