3,207 research outputs found

    Charmed Baryonium

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    We re-analyze the published data on the Y(4630) --> Lambda_c Lambdabar_c and the Y(4660) --> psi(2S) pi pi with a consistent Ansatz and we find that the two observations are likely to be due to the same state Y_B with M_{Y_B} = 4660.7 +- 8.7 MeV and Gamma_{Y_B} = 61 +- 23 MeV. Under this hypothesis and reanalizing also the e+e- --> J/psi pi pi gamma_ISR spectrum we extract B(Y_B --> Lambda_c Lambdabar_c) / B(Y_B --> psi(2S) pi pi) = 25 +- 7, B(Y_B --> J/psi pi pi) / B(Y_B --> psi(2S) pi pi) J/psi pi pi) / B(Y(4350) --> psi(2S) pi pi) psi(2S) sigma) / B (Y_B --> psi(2S) f_0)=2.0 +- 0.3. These conclusions strongly support the hypothesis of Y_B being the first observation of a charmed baryonium constituted by four quarks. From the analysis of the mass spectrum and the decay properties we show that Y(4350) and Y_B are respectively consistent with the ground state and first radial excitation of the L=1 state.Comment: Corrected phase space normalization in the fit

    High-resolution lightning detection and possible relationship with rainfall events over the Central Mediterranean area

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    Lightning activity is usually associated with precipitations events and represents a possible indicator of climate change, even contributing to its increase with the production of NOx gases. The study of lightning activity on long temporal periods is crucial for fields related to atmospheric phenomena from intense rain-related hazard processes to long-term climate changes. This study focuses on 19 years of lightning-activity data, recorded from Italian Lightning Detection Network SIRF, part of the European network EUCLID (European Cooperation for Lightning Detection). Preliminary analysis was dedicated to the spatial and temporal assessment of lightning through detection in the Central Mediterranean area, focusing on yearly and monthly data. Temporal and spatial features have been analyzed, measuring clustering through the application of global Moran’s I statistics and spatial local autocorrelation; a Mann–Kendall trend test was performed on monthly series aggregating the original data on a 5 × 5 km cell. A local statistically significant trend emerged from the analysis, suggesting a possible linkage between surface warming and lightning activity

    Geosites and geological landscapes of Liguria (Italy)

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    Liguria is a small region in Northwestern Italy which is characterized by significant and valuable geoheritage. The 1:250,000 map presented in this paper displays the 120 geosites of Liguria, officially approved by regional and national authorities, framed in the context of the geological landscapes of the region. The geological landscapes were obtained by categorizing and thematizing geological, lithological and geomorphological data in macro-units with similar characteristics. Protected areas (National parks, regional parks and natural reserves) and caves are also highlighted in the map. This work aims to give a better understanding of the Ligurian geoheritage, its relationship with the geological and geomorphological context, and the framework of protected areas. Thus, the present map can be a useful tool for developing effective geoheritage management and enhancement strategies

    The extended structure of the dwarf irregular galaxies Sextans A and Sextans B. Signatures of tidal distortion in the outskirts of the Local Group

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    We present a detailed study of the stellar and HI structure of the dwarf irregular galaxies SextansA and SextansB, members of the NGC3109 association. We use newly obtained deep (r~26.5) and wide field g,r photometry to extend the Surface Brightness (SB) profiles of the two galaxies down to mu_V~ 31.0 mag/arcsec^2. We find that both galaxies are significantly more extended than what previously traced with surface photometry, out to ~4 kpc from their centers along their major axis. Older stars are found to have more extended distribution with respect to younger populations. We obtain the first estimate of the mean metallicity for the old stars in SexB, from the color distribution of the Red Giant Branch, =-1.6. The SB profiles show significant changes of slope and cannot be fitted with a single Sersic model. Both galaxies have HI discs as massive as their respective stellar components. In both cases the HI discs display solid-body rotation with maximum amplitude of ~50 km/s (albeit with significant uncertainty due to the poorly constrained inclination), implying a dynamical mass ~10^{9}~M_sun, a mass-to-light ratio M/L_V~25 and a dark-to-barionic mass ratio of ~10. The distribution of the stellar components is more extended than the gaseous disc in both galaxies. We find that the main, approximately round-shaped, stellar body of Sex~A is surrounded by an elongated low-SB stellar halo that can be interpreted as a tidal tail, similar to that found in another member of the same association (Antlia). We discuss these, as well as other evidences of tidal disturbance, in the framework of a past passage of the NGC3109 association close to the Milky Way, that has been hypothesized by several authors and is also supported by the recently discovered filamentary configuration of the association itself.Comment: Accepted for publication by A&A. PdfLateX, 16 pages, 11 figures, 2 appendice

    Analysis of Y(4660) and related bound states with QCD sum rules

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    In this article, we take the vector charmonium-like state Y(4660) as a ψf0(980)\psi'f_0(980) bound state (irrespective of the hadro-charmonium and the molecular state) tentatively, study its mass using the QCD sum rules, the numerical value MY=4.71±0.26GeVM_Y=4.71\pm0.26 \rm{GeV} is consistent with the experimental data. Considering the SU(3) symmetry of the light flavor quarks and the heavy quark symmetry, we also study the bound states ψσ(4001200)\psi'\sigma(400-1200), Υ"f0(980)\Upsilon'"f_0(980) and Υ"σ(4001200)\Upsilon"'\sigma(400-1200) with the QCD sum rules, and make reasonable predictions for their masses.Comment: 18 pages, 32 figures, revised versio

    Geosites and geological landscape map of Liguria (Italy)

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    Since the beginning of the Third Millennium, an ever-increasing interest of geoheritage has been observed, either in scientific terms or in practical point of view, with the resulting socio-economic consequences. Geoheritage represents the basic element of the landscape and it often has strong links with other elements of the territory like historical geography, land-use setting, landscape protection, nature conservation, etc. Oneimportant link is tied to the environmental protection task, because most part of the Italian protected areas are mainly established above Earth Sciences features. Consequently, a lot of geosite sare included into these important natural sites. The issue of geoheritage and geosites has become object of national and regional laws: in Italy the cultural heritage and landscape code was issued in 2004 while in Liguria the Regional Law n. 39/2009 establishes the rules for the valorisation of the geodiversity, geosites and karst areas. Here we present an overview of geosites and geological landscape of Liguria (North West Italy); in addition to the recent regional database and georeferencing activities of the Ligurian geosites, through a reworking of a simplified geological map addressed also for non-geologists, a geotematic map has been defined. In particular, this product emphasizes the relationship between geology and landscape, showing how different rock masses produce several landforms of outstanding natural beauty in the ligurian territory. The map shows the basic concepts of geoscience by looking closely at the landscape we see in front of us every day. From the coast to the Alps and Apennines watershed, we identified several geological landscape units characterized by specific rock masses, soils and particular geological and geomorphological features, such as: 1) Palaeolandslides landscape; 2) Ligurian alluvial floodplains; 3)Ligurian coastal plains; 4) the Flysch rock masses; 5) Ophiolitic crags; 6) Conglomerate peaks; 7) Karstic massif; 8) Quartzite and Cherts rock masses; 9) Sandstone spurs; 10) Shales and schists domain; 11) Windows on the Paleozoic; 12) Plio- Quaternary landscape. More than 500 geosites classified in a recent specific regional database were then overlapped on the geological landscape units: they have been distinguished according to interest, for different geothematic categories, according to the proposal of enhancement. The Ligurian geosites and geological landscape overview map could represents a friendly tool to identify the most relevant regional geological heritage

    Urban geomorphology of Genoa old city (Italy)

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    A multi-year geomorphological surveys of the city of Genoa allowed the creation of an original geomorphological map of the urban environment. The city of Genoa is internationally known for the importance of its port and for the presence of a historic city center recognized as an UNESCO World Heritage since 2006. The research methodology was based on the structuring and analysis of a multi-source geodatabase consisting of information acquired from scientific literature and technical reports, historical and recent photographs and maps, geological and environmental data related to land planning plans, original data from field surveys. Work phases of data elaboration included: 1) a multi-temporal cartographic comparison from the eighteenth-century to year 2016; 2) an analysis of aerial photographs in the period 1936-2016; 3) the interpretation of boreholes data; 4) both surface and underground geomorphological observations within the city centre, by means of field surveys and speleological techniques. The recognition of the former geomorphological setting on which the historical nucleus of Genoa has developed, and the interpretation of its paleogeographic, geological and tectonic conditions, are not an easy task: since the High Middle Ages of the Maritime Republic of Genoa, the superposition of multiple phases of urban sprawl has obliterated original geomorphic conditions. However, interpretation of the rich geodatabase allowed to classify landforms, processes and surficial deposits with respect to their original environment and morphogenesis, i.e due to: running waters, gravity, karst, action of the sea; but, above all, due to human activities. In fact, the entire study area has undergone continuous modifications by man through the all considered time interval, as shown by artificial land fillings at the seaside, alteration of the river network, excavations and fills on the slopes, with the highlighting of significant anthropogenic urban landforms. The geomorphological map support both a morpho-evolutionary and a functional approach to the geomorphological landscape the of Genoa old city: therefore, it can be a useful tool for land planning, also aimed at reducing the geo-hydrological risk that characterizes the urban area

    Geo-hydrological risk mitigation in a terraced landscape: LiDAR data analysis in the Portofino natural Park, Italy

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    Modification of steep slopes with man-made terraces is an ancient and widespread habit in many areas of the world. If the modification assures agricultural practices in mountainous areas, it results even as an important interference with the geomorphic processes: important quantities of soil and sediments are subtracted to the degradation processes and, in case of total abandonment of terraces, they result again available to erosion. Intense rain event may cause partial instability or even collapse of the anthropogenic structures, configuring terraces as an additional source of Geo-hydrological hazard. Recent events in Liguria - northern Italy, in Cinque Terre 2011 and Leivi (Chiavari) 2014, caused damages and even casualties due to the sudden collapse of terraced slopes. A crucial point in assessing the potential hazard caused by abandoned terraced slopes is identifying their real extension. LiDAR data analysis is an important assessment tool particularly in strong steepness areas due to the capability of recognizing linear regular structures. In the present research LiDAR data analysis has been used to identify terraces in the Portofino Natural Park area (Liguria region, Italy) as one of the preliminary activities of the RECONECT European Union\u2019s Horizon 2020 Research and Innovation Programme project. The project plans to realize nature based solutions to mitigate geohydrological risk in two pilot areas in the Portofino promontory and the recovery of terraces is one of the foreseen actions. Mapping terraces is the first step to evaluate the potential risk associated to the possible instability processes and the interventions to be realized. Land use evolution in the area from 1800 to present have been indeed found through historical maps examination and used in conjunction with LiDAR analysis results
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