5,673 research outputs found

    Spectral function at high missing energies and momenta

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    The nuclear spectral function at high missing energies and momenta has been determined from a self-consistent calculation of the Green's function in nuclear matter using realistic nucleon-nucleon interactions. The results are compared with recent experimental data derived from (e,epe,e'p) reactions on 12C^{12}C. A rather good agreement is obtained if the Green's functions are calculated in a non-perturbative way.Comment: 10 pages, 3 figure

    Incomplete cost pass-through under deep habits

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    A number of empirical studies document that marginal cost shocks are not fully passed through to prices at the firm level and that prices are substantially less volatile than costs. We show that in the relative-deep-habits model of Ravn, Schmitt-Grohe, and Uribe (2006), firm-specific marginal cost shocks are not fully passed through to product prices. That is, in response to a firm-specific increase in marginal costs, prices rise, but by less than marginal costs leading to a decline in the firm-specific markup of prices over marginal costs. Pass-through is predicted to be even lower when shocks to marginal costs are anticipated by firms. In our model, unanticipated firm-specific cost shocks lead to incomplete pass-through (or a decline in markups) of about 20 percent and anticipated cost shocks are associated with incomplete pass-through of about 50 percent. The model predicts that cost pass-through is increasing in the persistence of marginal cost shocks and U-shaped in the strength of habits. The relative-deep-habits model implies that conditional on marginal cost disturbances, prices are less volatile than marginal costs

    The macroeconomics of subsistence points

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    This paper explores the macroeconomic consequences of preferences displaying a subsistence point. It departs from the existing related literature by assuming that subsistence points are specific to each variety of goods rather than to the composite consumption good. We show that this simple feature makes the price elasticity of demand for individual goods procyclical. As a result, markups behave countercyclically in equilibrium. This implication is in line with the available empirical evidence

    Fluence Dependence of Charge Collection of irradiated Pixel Sensors

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    The barrel region of the CMS pixel detector will be equipped with ``n-in-n'' type silicon sensors. They are processed on DOFZ material, use the moderated p-spray technique and feature a bias grid. The latter leads to a small fraction of the pixel area to be less sensitive to particles. In order to quantify this inefficiency prototype pixel sensors irradiated to particle fluences between 4.7×10134.7\times 10^{13} and 2.6\times 10^{15} \Neq have been bump bonded to un-irradiated readout chips and tested using high energy pions at the H2 beam line of the CERN SPS. The readout chip allows a non zero suppressed analogue readout and is therefore well suited to measure the charge collection properties of the sensors. In this paper we discuss the fluence dependence of the collected signal and the particle detection efficiency. Further the position dependence of the efficiency is investigated.Comment: 11 Pages, Presented at the 5th Int. Conf. on Radiation Effects on Semiconductor Materials Detectors and Devices, October 10-13, 2004 in Florence, Italy, v3: more typos corrected, minor changes required by the refere

    Be a Hero Too

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    This children\u27s book explains COVID-19 and how to decrease the incidence of transmissions.https://digitalcommons.unmc.edu/com_peds_books/1000/thumbnail.jp

    Building CMS Pixel Barrel Detectur Modules

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    For the barrel part of the CMS pixel tracker about 800 silicon pixel detector modules are required. The modules are bump bonded, assembled and tested at the Paul Scherrer Institute. This article describes the experience acquired during the assembly of the first ~200 modules.Comment: 5 pages, 7 figures, Vertex200

    Tests of silicon sensors for the CMS pixel detector

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    The tracking system of the CMS experiment, currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland), will include a silicon pixel detector providing three spacial measurements in its final configuration for tracks produced in high energy pp collisions. In this paper we present the results of test beam measurements performed at CERN on irradiated silicon pixel sensors. Lorentz angle and charge collection efficiency were measured for two sensor designs and at various bias voltages.Comment: Talk presented at 6th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors, September 29-October 1, 2003, Firenze, Italy. Proceedings will be published in Nuclear Instr. & Methods in Phys. Research, Section

    High-performance functional renormalization group calculations for interacting fermions

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    We derive a novel computational scheme for functional Renormalization Group (fRG) calculations for interacting fermions on 2D lattices. The scheme is based on the exchange parametrization fRG for the two-fermion interaction, with additional insertions of truncated partitions of unity. These insertions decouple the fermionic propagators from the exchange propagators and lead to a separation of the underlying equations. We demonstrate that this separation is numerically advantageous and may pave the way for refined, large-scale computational investigations even in the case of complex multiband systems. Furthermore, on the basis of speedup data gained from our implementation, it is shown that this new variant facilitates efficient calculations on a large number of multi-core CPUs. We apply the scheme to the tt,tt' Hubbard model on a square lattice to analyze the convergence of the results with the bond length of the truncation of the partition of unity. In most parameter areas, a fast convergence can be observed. Finally, we compare to previous results in order to relate our approach to other fRG studies.Comment: 26 pages, 9 figure

    Soft Fermi Surfaces and Breakdown of Fermi Liquid Behavior

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    Electron-electron interactions can induce Fermi surface deformations which break the point-group symmetry of the lattice structure of the system. In the vicinity of such a "Pomeranchuk instability" the Fermi surface is easily deformed by anisotropic perturbations, and exhibits enhanced collective fluctuations. We show that critical Fermi surface fluctuations near a d-wave Pomeranchuk instability in two dimensions lead to large anisotropic decay rates for single-particle excitations, which destroy Fermi liquid behavior over the whole surface except at the Brillouin zone diagonal.Comment: 12 pages, 2 figures, revised version as publishe
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