16,144 research outputs found

    The Euro changeover and price adjustments in Italy

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    By estimating a staggered price model over the period 1980q1-2010q2, this paper documents that, after the euro changeover, Italian retailers have increased the number of price adjustments, which has translated into a higher inflation rate, with a detrimental effect on the competitiveness of the Italian economy

    Hard Cosmic Ray Sea in the Galactic Center: a consistent interpretation of H.E.S.S. and Fermi-LAT γ\gamma-ray data

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    We present a novel interpretation of the gamma-ray diffuse emission measured by H.E.S.S. in the Galactic Center (GC) region and the Galactic ridge. Our starting base is an updated analysis of PASS8 Fermi-LAT data, which allows to extend down to few GeV the spectra measured by H.E.S.S. and to infer the primary CR radial distribution above 100 GeV. We compare those results with a CR transport model assuming a harder scaling of the diffusion coefficient with rigidity in the inner Galaxy. Such a behavior reproduces the radial dependence of the CR spectral index recently inferred from Fermi-LAT measurements in the inner GP. We find that, in this scenario, the bulk of the Galactic ridge emission can be naturally explained by the interaction of the diffuse, steady-state Galactic CR sea interacting with the gas present in the Central molecular zone. The evidence of a GC PeVatron is significantly weaker than that inferred adopting a conventional (softer) CR sea.Comment: Oral contribution to the International Cosmic Ray Conference (ICRC 2017), 12-20 July 2017, Bexco, Busan, Kore

    Topological mass mechanism and exact fields mapping

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    We present a class of mappings between models with topological mass mechanism and purely topological models in arbitrary dimensions. These mappings are established by directly mapping the fields of one model in terms of the fields of the other model in closed expressions. These expressions provide the mappings of their actions as well as the mappings of their propagators. For a general class of models in which the topological model becomes the BF model the mappings present arbitrary functions which otherwise are absent for Chern-Simons like actions. This work generalizes the results of [1] for arbitrary dimensions.Comment: 11 page

    The helium spread in the Globular cluster 47 Tuc

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    Spectroscopy has shown the presence of the CN band dicothomy and the Na-O anticorrelations for 50--70% of the investigated samples in the cluster 47 Tuc, otherwise considered a "normal" prototype of high metallicity clusters from the photometric analysis. Very recently, the re-analysis of a large number of archival HST data of the cluster core has been able to put into evidence the presence of structures in the Sub Giant Branch: it has a brighter component with a spread in magnitude by ∼\sim0.06 mag and a second one, made of about 10% of stars, a little fainter (by ∼\sim0.05 mag). These data also show that the Main Sequence of the cluster has an intrinsic spread in color which, if interpreted as due to a small spread in helium abundance, suggests Δ\DeltaY∼\sim0.027. In this work we examine in detail whether the Horizontal Branch morphology and the Sub Giant structure provide further independent indications that a real --although very small-helium spread is present in the cluster. We re--analyze the HST archival data for the Horizontal Branch of 47 Tuc, obtaining a sample of ∼\sim500 stars with very small photometric errors, and build population synthesis based on new models to show that its particular morphology can be better explained by taking into account a spread in helium abundance of 2% in mass. The same variation in helium is able to explain the spread in luminosity of the Sub Giant Branch, while a small part of the second generation is characterized by a small C+N+O increase and provides an explanation for the fainter Sub Giant Branch. We conclude that three photometric features concur to form the paradigm that a small but real helium spread is present in a cluster that has no spectacular evidence for multiple populations like those shown by other massive clusters.Comment: Accepted for publication in the MNRAS on 2010 June 8. Received 2010 May 19; in original form 2010 February 9. 7 pages and 3 figures. No table

    KLOE results at the Frascati ϕ\phi-factory DAΦ\PhiNE

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    The KLOE experiment at the Frascati ϕ\phi-factory DAΦ\PhiNE has collected about 0.5 fb−1^{-1} of data till the end of the year 2002. These data allow to perform a wide physics program, ranging from the physics of charged and neutral kaons to radiative ϕ\phi-decays. Results are presented for the KLK_L lifetime and the semileptonic processes KS,L→πeνK_{S,L} \to \pi e \nu. From the light meson spectroscopy program, results on the decays ϕ→f0(980)γ,a0(980)γ\phi \to f_0(980)\gamma, a_0(980)\gamma as well as ϕ→ηγ,η′γ\phi \to \eta \gamma, \eta' \gamma are presented.Comment: 5 pages, 3 figures, Proceedings contribution to the 10th Int. Symposium on "Meson-Nucleon Physics and the Structure of the Nucleon" (MENU04), Beijing, China, Aug. 30 - Sept. 4, 200
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