Measurement of CP observables in B± → D(⁎)K± and B± → D(⁎)π± decays

Measurements of CP observables in B ± →D (⁎) K ± and B ± →D (⁎) π ± decays are presented, where D (⁎) indicates a neutral D or D ⁎ meson that is an admixture of D (⁎)0 and D¯ (⁎)0 states. Decays of the D ⁎ meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K ± π ∓ , K + K − and π + π − final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb −1 taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B ± →D ⁎ K ± and B ± →D ⁎ π ± decays using a partial reconstruction method is the first of its kind, while the measurement of B ± →DK ± and B ± →Dπ ± decays is an update of previous LHCb measurements. The B ± →DK ± results are the most precise to date

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

First observation of forward Z→bbˉZ \rightarrow b \bar{b} production in pppp collisions at s=8\sqrt{s}=8 TeV

The decay Z→bb¯ is reconstructed in pp collision data, corresponding to 2 fb −1 of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of s=8 TeV. The product of the Z production cross-section and the Z→bb¯ branching fraction is measured for candidates in the fiducial region defined by two particle-level b -quark jets with pseudorapidities in the range 2.220 GeV and dijet invariant mass in the range 4520$GeV and dijet invariant mass in the range$45 < m_{jj} < 165$GeV. From a signal yield of$5462 \pm 763$$Z \rightarrow b \bar{b}$events, where the uncertainty is statistical, a production cross-section times branching fraction of$332 \pm 46 \pm 59$pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the$Z \rightarrow b \bar{b}$production in the forward region of$pp$ collisions

Il bacino dell'Arno

La tavola inserita nell’Atlante tematico delle acque d’Italia, propone un'analisi dell'ambiente attraversato dal fiume, mettendo in particolare risalto gli interventi idraulici, l'importanza che il fiume ha rivestito in varie epoche storiche e, in chiave attuale, come l'Arno influenzi la geografia antropica della Toscana, le attività economiche in prossimità delle sue sponde la rete dei trasporti. Vengono, altresì, messe in luce le principali trasformazioni del paesaggio e dell'utilizzo del suol

Glacier retreat in the Maritime Alps area

In the southernmost tract of the Alps (Italian-French Maritime Alps), extensively covered by glaciers during the Last Glacial Maximum, about thirty small glaciers were present by the end of the Little Ice Age. The aim of this paper is to document the progressive decrease towards exhaustion of these glaciers, located at the latitude of 44° N, highlighting the factors affecting their retreat. All available data sources were investigated for this work including: the yearly glaciers fluctuations record, comparative analyses of historical maps and multitemporal oblique photographs and direct surveys in the field. The history of the Maritime Alps glaciers fluctuations was thoroughly reconstructed. Stationary conditions were observed from 1896 up to the beginning of the 1930s; since then they underwent phases of withdrawal with variable intensity. In the early 1990s, only six glaciers were still present, the extensions of which were all dramatically reduced. In the past two decades, the Maritime Alps glacier fronts experienced a global retreat of about 100 m, with a sharp acceleration after 2002. Currently ice patches along cirque walls and/or semi-buried lenses of ice are still present; morphological evidence of permafrost creeping in the glacier forefield accounts for the incipient transition to periglacial landforms (i.e. rock glaciers). The main factors controlling glaciers retreat seem to have been their original extension at the beginning of the current regressive phase and their distance from the main chain divide. From a climatic point of view unfavourable factors for glaciers persistence have been in the last decades a remarkable and sharp temperature increase, a decrease in winter snowfall and a shift of the rainfall peak from autumn to spring

La geomorfologia dell'alta Val Parma (Appennino settentrionale)

Riv. Geogr. Ital

Contributo alla conoscenza dei terrazzi marini della Liguria fra Genova Nervi e Camogli

This paper focuses on the evidence of past sea levels recognized in a specific tract of the Eastern Liguria coast, located immediately eastward the city of Genoa. From a geological point of view, the study area presents a good uniformity since only Antola Unit, consisting of marls, limestone, calcarenite, sandstone and shale, outcrops here. The geomorphological survey of the coast between Nervi and Camogli, provides well-defined markers of at least two highstands, in the form of a staircase of marine terraces, within an altitude span ranging from present-day sea level to the 34 m contour line. Very often these terraces appear covered by continental sediments or altered from erosion processes, uplift and the strong human impact that affects the study area. Although no patches of the original marine deposit of these terraces have been found yet, they are currently undated and their age attribution is attempted in this paper by means of correlation with dated shorelines. Despite of the underlined difficulties, the altitude of the terraces inner margins were obtained on the base of field measurements and two orders of terraces were identified. The terraced landforms of the upper order (I), with inner margins ranging between 24 and 34 m, are developed with few interruptions along the studied stretch of coast and are also often overlain by continental deposits due to alluvial fan or landslide. The cluster value for the upper order is 27 +1/-6 that is the median value of the measured inner margins with the assumed error, related to the inaccuracy of the measurement instrument (±1 m) and the evaluation of the sediment thickness (+5 m). The second order of terraces are characterized by an elevation of the inner margin ranging between 3-5 m a.s.l. The marker of this order is represented by platform of marine abrasion cut in the rock, without sediments on the surface, often affected by weathering. The upper group of terraces could be attributed to the MIS 5.5 highstand for correlation with a dated shoreline 30 km eastward the study area; consequently the lower group are in this hypothesis attributed to MIS 5.3 or 5.1. Another hypothesis, based on the correlation with the Western Liguria data, attributes the lower order to the M.I.S. 5.5 and the upper order to a previous isotopic stage. Considering the available data, the authors don't draw any conclusion about the geodynamic behaviour of the study area. In fact a different uplift rate would derive from each of the two proposed hypotheses and consequently a different vertical displacement for the two tracts of coast