2,814 research outputs found

    Improving bounds on flavor changing vertices in the two Higgs doublet model from BBˉB-\bar{B} mixing

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    We find some constraints on the flavor changing vertices of the two Higgs doublet model, from the \Delta M_{B_{d}} measurement. Although bounds from this observable have already been considered, this paper takes into account the role of a new operator not included previously, as well as the vertices \xi_{bb}, \xi_{tc} and \xi_{sb}. Using the Cheng-Sher parametrization, we found that for a relatively light charged Higgs boson (200-300 GeV), we get that \lambda _{tt}<1, while the parameter \lambda_{bb} could have values up to about 50. In addition, we use bounds for \lambda_{tt} and \lambda_{bb} obtained from B^{0}->X_{s}\gamma at next to leading order, and studied the case where the only vanishing vertex factors are the ones involving quarks from the first family. We obtained that \Delta M_{B_{d}} is not sensitive to the change of the parameter \lambda_{sb}, while \lambda_{tc}<1Comment: 4 pages, 1 figure, LaTeX2

    Symmetric discrete coherent states for n qubits

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    We put forward a method of constructing discrete coherent states for n qubits. After establishing appropriate displacement operators, the coherent states appear as displaced versions of a fiducial vector that is fixed by imposing a number of natural symmetry requirements on its Q-function. Using these coherent states we establish a partial order in the discrete phase space, which allows us to picture some n-qubit states as apparent distributions. We also analyze correlations in terms of sums of squared Q-functions.Comment: Published in J. Phys. A. Special issue on Coherent State

    Delta rho pi interaction leading to N* and Delta* resonances

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    We have performed a calculation for the three body Δρπ\Delta \rho \pi system by using the fixed center approximation to Faddeev equations, taking the interaction between Δ\Delta and ρ\rho, Δ\Delta andπ\pi, and ρ\rho and π\pi from the chiral unitary approach. We find several peaks in the modulus squared of the three-body scattering amplitude, indicating the existence of resonances, which can be associated to known I=1/2,3/2I=1/2, 3/2 and JP=1/2+,3/2+J^P=1/2^+, 3/2^+ and 5/2+5/2^+ baryon states.Comment: Presented at the 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, 30 August - 3 September 201

    A column-store meets the point clouds

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    Dealing with LIDAR data in the context of database management systems calls for a re-assessment of their functionality, performance, and storage/processing limitations. The territory for efficient and scalable processing of LIDAR repositories using GIS enabled database systems is still largely unexplored. Bringing together hard core database management experts and GIS application developers is a sine qua non to advance the state of the art. In particular to assess the relative merits of both traditional row-based database engines and the modern column-oriented database engines

    Very Low Temperature Tunnelling Spectroscopy in the heavy fermion superconductor PrOs4_4Sb12_{12}

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    We present scanning tunnelling spectroscopy measurements on the heavy fermion superconductor PrOs4_4Sb12_{12}. Our results show that the superconducting gap opens over a large part of the Fermi surface. The deviations from isotropic BCS s-wave behavior are discussed in terms of a finite distribution of values of the superconducting gap.Comment: 4 pages, 4 figure

    Perturbations of anti-de Sitter black holes

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    I review perturbations of black holes in asymptotically anti-de Sitter space. I show how the quasi-normal modes governing these perturbations can be calculated analytically and discuss the implications on the hydrodynamics of gauge theory fluids per the AdS/CFT correspondence. I also discuss phase transitions of hairy black holes with hyperbolic horizons and the dual superconductors emphasizing the analytical calculation of their properties.Comment: 25 pages, 4 figures, prepared for the proceedings of the 5th Aegean Summer School "From Gravity to Thermal Gauge Theories: the AdS/CFT Correspondence," Milos, Greece, September 2009
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