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

A narrow dip structure has been observed at 1.9 GeV/c$^2$ in a study of diffractive photoproduction of the $~3\pi^+3\pi^-$ 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

The $B^0$-$\bar B^0$ 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 $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Search for long-lived doubly charged Higgs bosons in p(p)over-bar collisions at root s=1.96 TeV

We present a search for long-lived doubly charged Higgs bosons (H+/-+/-), with signatures of high ionization energy loss and muonlike penetration. We use 292 pb(-1) of data collected in p (p) over bar collisions at root s=1.96 TeV by the CDF II detector at the Fermilab Tevatron. Observing no evidence of long-lived doubly charged particle production, we exclude H-L(+/-+/-) and H-R(+/-+/-) bosons with masses below 133 GeV/c(2) and 109 GeV/c(2), respectively. In the degenerate case we exclude H+/-+/- mass below 146 GeV/c(2). All limits are quoted at the 95% confidence level

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

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

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