27 research outputs found

    First observation of Bs -> D_{s2}^{*+} X mu nu decays

    Get PDF
    Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width.Comment: 8 pages 2 figures. Published in Physics Letters

    Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV

    Get PDF
    The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.Comment: 6+18 pages, 6 figures, updated author lis

    The PrĂŒm Regime: Situated Dis/Empowerment in Transnational DNA Profile Exchange

    Get PDF
    This paper takes critique of surveillance studies scholars of the shortcomings of the panoptic model for analysing contemporary systems of surveillance as a starting point. We argue that core conceptual tools, in conjunction with an under-conceptualization of agency, privilege a focus on the oppressive elements of surveillance. This often yields unsatisfying insights to why surveillance works, for whom, and at whose costs. We discuss the so-called PrĂŒm regime, pertaining to transnational data exchange for forensic and police use in the EU, to illustrate how—by articulating instances of what we call ‘situated dis/empowerment’—agency can be better conceptualized, sharpening our gaze for the large extent to which the empowering and disempowering effects of surveillance depend on each other
    corecore