14,928 research outputs found

    Light flavor hadron spectra at low pTp_{T} and search for collective phenomena in high multiplicity pp, p-Pb and Pb-Pb collisions measured with the ALICE experiment

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    Comprehensive results on transverse momentum distributions and their ratios for identified light flavor hadrons (π\pi, K, p) at low pTp_{T} and mid-rapidity as a function of charged particle multiplicity are reported for pp collisions at 7 TeV. Particle mass dependent hardening of the spectral shapes in Pb-Pb collisions at 2.76 TeV were attributed to hydrodynamical flow and quantitatively parameterized with Boltzmann-Gibbs Blast Wave fits. In this contribution, we investigate the existence of collective phenomena in small systems: pp, p-Pb and peripheral Pb-Pb where similar patterns are observed in multiplicity dependent studies.Comment: Proceedings of Quark Matter 2014 conference, May 19-24, 201

    Cost-benefit Analysis for Modernization the Agricultural Working Roads

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    To achieve this CBA we use a series of specific steps and process documentation and references provided by the guide in preparation for submission of projects CBA as 125/FEADR/2010. The content of the cost-benefit analysis it is described in the document developed by the European Agricultural Fund for Rural Development ”Recommendations for developing cost-benefit analysis”. For a clear image of the situation described in the project we will try to analyze three scenarios. The method used in developing the financial analysis is ” discounted cash flow ”. The chosen project is an example, but the dates and figures are real.CBA, FEADR, scenarios, financial analysis, cash flow

    A construction of integrated vertex operator in the pure spinor sigma-model in AdS5xS5

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    Vertex operators in string theory come in two varieties: integrated and unintegrated. Understanding both types is important for the calculation of the string theory amplitudes. The relation between them is a descent procedure typically involving the b-ghost. In the pure spinor formalism vertex operators can be identified as cohomology classes of an infinite-dimensional Lie superalgebra formed by covariant derivatives. We show that in this language the construction of the integrated vertex from an unintegrated vertex is very straightforward, and amounts to the evaluation of the cocycle on the generalized Lax currents.Comment: LaTeX 13pp; v2: correction in Section 4.

    Z2\mathbb Z_2 fractional topological insulators in two dimensions

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    We propose a simple microscopic model to numerically investigate the stability of a two dimensional fractional topological insulator (FTI). The simplest example of a FTI consists of two decoupled copies of a Laughlin state with opposite chiralities. We focus on bosons at half filling. We study the stability of the FTI phase upon addition of two coupling terms of different nature: an interspin interaction term, and an inversion symmetry breaking term that couples the copies at the single particle level. Using exact diagonalization and entanglement spectra, we numerically show that the FTI phase is stable against both perturbations. We compare our system to a similar bilayer fractional Chern insulator. We show evidence that the time reversal invariant system survives the introduction of interaction coupling on a larger scale than the time reversal symmetry breaking one, stressing the importance of time reversal symmetry in the FTI phase stability. We also discuss possible fractional phases beyond ν=1/2\nu = 1/2.Comment: 15 pages, 18 figure

    Upper Limits on the 21 cm Power Spectrum at z = 5.9 from Quasar Absorption Line Spectroscopy

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    We present upper limits on the 21 cm power spectrum at z=5.9z = 5.9 calculated from the model-independent limit on the neutral fraction of the intergalactic medium of xHI<0.06+0.05 (1σ)x_{\rm H{\small I }} < 0.06 + 0.05\ (1\sigma) derived from dark pixel statistics of quasar absorption spectra. Using 21CMMC, a Markov chain Monte Carlo Epoch of Reionization analysis code, we explore the probability distribution of 21 cm power spectra consistent with this constraint on the neutral fraction. We present 99 per cent confidence upper limits of Δ2(k)<10\Delta^2(k) < 10 to 20 mK220\ {\rm mK}^2 over a range of kk from 0.5 to $2.0\ h{\rm Mpc}^{-1},withtheexactlimitdependentonthesampled, with the exact limit dependent on the sampled kmode.Thislimitcanbeusedasanulltestfor21cmexperiments:adetectionofpowerat mode. This limit can be used as a null test for 21 cm experiments: a detection of power at z=5.9$ in excess of this value is highly suggestive of residual foreground contamination or other systematic errors affecting the analysis.Comment: 5 pages, 1 figure, accepted to MNRAS letter
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