161 research outputs found

    Evidence for a narrow dip structure at 1.9 GeV/c2^2 in 3π+3π3\pi^+ 3\pi^- diffractive photoproduction

    Full text link
    A narrow dip structure has been observed at 1.9 GeV/c2^2 in a study of diffractive photoproduction of the  3π+3π~3\pi^+3\pi^- final state performed by the Fermilab experiment E687.Comment: The data of Figure 6 can be obtained by downloading the raw data file e687_6pi.txt. v5 (2nov2018): added Fig. 7, the 6 pion energy distribution as requested by a reade

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

    Get PDF
    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Measurement of the W+W- Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Dilepton Events

    Get PDF
    We present a measurement of the W+W- production cross section using 184/pb of ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W- -> l+l-vvbar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0+2.2-0.8 events. The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-) = 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the Standard Model expectation.Comment: 8 pages, 2 figures, 2 tables. To be submitted to Physical Review Letter

    Volatile contents of Kermadec Arc�Havre Trough pillow glasses: Fingerprinting slab-derived aqueous fluids in the mantle sources of arc and back-arc lavas

    No full text
    Aqueous fluids and sediment melts from subducting oceanic lithosphere are the driving force for the refertilisation of the mantle overlying subduction zones. Volatile elements in particular play an important role in the generation of aqueous fluids and the transport of fluid mobile elements. Here we report volatile contents of quenched glasses from pillow-lava rims in the Kermadec Arc�Havre Trough subduction system to provide constraints on the source, generation, and composition of slab-derived aqueous fluids. Water (1.5 wt.% in glasses, 2.5 wt.% in two melt inclusions), carbon (up to 16 ppm in glasses, 180 ppm in one inclusion) and sulphur (< 700 ppm) contents of all glasses are consistent with degassing of volatiles, which migrated from the melt, through growing vesicles, and into the water column, even in samples collected at depths of up to 3000 m. By contrast, halogen contents have not been affected by degassing or any other secondary processes such as assimilation of seawater. Fluorine contents (250�520 ppm) can be obtained almost entirely from melting of depleted mantle similar to that which generates mid-ocean ridge basalt. However, Cl (650�3000 ppm) is enriched tenfold compared to depleted mantle-derived lavas. A minimum of 70% H2O, > 80% Ba and Pb, and > 98% of Cl is required to be derived from aqueous slab-derived fluids. We propose a single homogenous reservoir for the aqueous fluid source. This reservoir is most likely to be hydrated serpentinite formed above the subducting slab by fluids derived from altered oceanic crust and subducting sediment. Dehydration of the serpentinite occurs as it descends into the mantle, transporting fluid mobile elements into the overlying mantle and triggering partial melting. The similarity of aqueous fluid compositions derived for other oceanic arcs suggests that this process may occur in arc systems worldwide

    Representation and Management of Complex ‘Narrative’ Information

    No full text
    International audienceIn this paper, we evoke first the ubiquity and the importance of the so-called “non-fictional” narrative information. We show then that the usual knowledge representation and ontological techniques have difficulties in finding complete solutions for representing and using this type of information. We supply then some details about NKRL, a representation and querying/inferencing environment especially created for an ‘intelligent’ exploitation of (non-fictional) narratives. The paper will be illustrated with some examples concerning recent concrete applications of this language/environment
    corecore