24,171 research outputs found

    Measurements of CP violation in B mixing through BJ/ψXB \to J/\psi X decays at LHCb

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    B mesons provide an ideal laboratory for measurements of CP violation and searches for CP violation beyond the Standard Model. Recent measurements of the mixing phases of the Bs0B_s^0 and B0B^0 mesons, ϕs\phi_s and sin2β\sin2\beta, using decays to J/ψXJ/\psi X final states are presented. In view of future improved measurements, a good understanding of pollution from sub-leading penguin topologies in these decays is needed. Those can be probed using suppressed decays like Bs0J/ψKS0B_s^0 \to J/\psi K_S^0 and Bs0J/ψK0B_s^0 \to J/\psi \overline{K}^{*0}. Recent results using these decay modes are presented.Comment: Proceedings for EPS-HEP 2015. Updated introductio

    Exotic hadron spectroscopy at the LHCb experiment

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    The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from proton-proton collisions at the CERN Large Hadron Collider. During Run 1, it has recorded the world's largest data sample of beauty and charm hadrons, enabling precise studies into the spectroscopy of such particles, including discoveries of new states and measurements of their masses, widths and quantum numbers. An overview of recent LHCb results in the area of exotic hadron spectroscopy is presented, focussing on the discovery of the first pentaquark states in the Λb0J/ψpK\Lambda_b^0 \to J/\psi p K^- channel and a search for them in the related Λb0J/ψpπ\Lambda_b^0 \to J/\psi p\pi^- mode. The LHCb non-confirmation of the D0 tetraquark candidate in the Bs0π+B_s^0\pi^+ invariant mass spectrum is presented.Comment: 4 pages, 8 figures, proceedings for Rencontres de Blois 201

    Fermi-Bose Correspondence and Bose-Einstein Condensation in The Two-Dimensional Ideal Gas

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    The ideal uniform two-dimensional (2D) Fermi and Bose gases are considered both in the thermodynamic limit and the finite case. We derive May's Theorem, viz. the correspondence between the internal energies of the Fermi and Bose gases in the thermodynamic limit. This results in both gases having the same heat capacity. However, as we shall show, the thermodynamic limit is never truly reached in two dimensions and so it is essential to consider finite-size effects. We show in an elementary manner that for the finite 2D Bose gas, a pseudo-Bose-Einstein condensate forms at low temperatures, incompatible with May's Theorem. The two gases now have different heat capacities, dependent on the system size and tending to the same expression in the thermodynamic limit.Comment: 18 pages, 3 figures in EPS format, to be published in Journal of Low Temperature Physic

    A Note on Equilibrium Systems from a Dialectical /tensional/ Point of View

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    Equilibrium systems form dialectical or tensional point of vie

    NAP (davunetide) rescues neuronal dysfunction in a Drosophila model of tauopathy

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    Alzheimer’s disease (AD) is a devastating neurodegenerative disease causing irreversible cognitive decline in the elderly. There is no disease-modifying therapy for this condition and the mechanisms underpinning neuronal dysfunction and neurodegeneration are unclear. Compromised cytoskeletal integrity within neurons is reported in AD. This is believed to result from loss-of-function of the microtubule-associated protein tau, which becomes hyper-phosphorylated and deposits into neurofibrillary tangles in AD. We have developed a Drosophila model of tauopathy in which abnormal human tau mediates neuronal dysfunction characterised by microtubule destabilisation, axonal transport disruption, synaptic defects and behavioural impairments. Here we show that a microtubule-stabilising drug, NAPVSIPQ (NAP), prevents as well as reverses these phenotypes even after they have become established. Moreover, it does not alter abnormal tau levels indicating that it by-passes toxic tau altogether. Thus, microtubule stabilisation is a disease-modifying therapeutic strategy protecting against tau-mediated neuronal dysfunction, which holds great promise for tauopathies like AD

    Caldolysin, a highly active protease from an extremely Thermophilic Bacterium

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    Proteases comprise a significant proportion of those proteins which have been subject to detailed characterisation (amino acid sequence and high resolution crystallographic analysis). The extent of research interest in proteolytic enzymes reflects both their historical status, and the practical advantages of proteases as research subjects (available in quantity, extracellular etc.) widely occurring
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