52 research outputs found

    Scale Dependence of Halo Bispectrum from Non-Gaussian Initial Conditions in Cosmological N-body Simulations

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    We study the halo bispectrum from non-Gaussian initial conditions. Based on a set of large NN-body simulations starting from initial density fields with local type non-Gaussianity, we find that the halo bispectrum exhibits a strong dependence on the shape and scale of Fourier space triangles near squeezed configurations at large scales. The amplitude of the halo bispectrum roughly scales as fnl2f_nl^2. The resultant scaling on the triangular shape is consistent with that predicted by Jeong & Komatsu based on perturbation theory. We systematically investigate this dependence with varying redshifts and halo mass thresholds. It is shown that the fnlf_nl dependence of the halo bispectrum is stronger for more massive haloes at higher redshifts. This feature can be a useful discriminator of inflation scenarios in future deep and wide galaxy redshift surveys.Comment: 27 pages, 10 figures; revised argument in section 6, added appendix C, JCAP accepted versio

    Measurement of ϒ production in pp collisions at √s = 2.76 TeV

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    The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→Ό+Ό− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→Ό+Ό− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→Ό+Ό− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

    Averaging lifetimes for B hadron species

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    The measurement of the lifetimes of the individual B species are of great interest. Many of these measurements are well below the 10% level of precision. However, in order to reach the precision necessary to test the current theoretical predictions, the results from different experiments need to be averaged together. Therefore, the relevant systematic uncertainties of each measurement need to be well defined in order to understand the correlations between the results from different experiments. In this paper we discuss the dominant sources of systematic errors which lead to correlations between the different measurements. We point out problems connected with the conventional approach of combining lifetime data and discuss methods which overcome these problems. (orig.)Available from TIB Hannover: RR 2916(96-04) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper

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    Contains fulltext : 126057.pdf (preprint version ) (Open Access
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