392 research outputs found
The population of New Hampshire, Station Bulletin, no.458
The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire
The laurentian record of neoproterozoic glaciation, tectonism, and eukaryotic evolution in Death Vally, California
Neoproterozoic strata in Death Valley, California contain eukaryotic microfossils and glacial deposits that have been used to assess the severity of putative Snowball Earth events and the biological response to extreme environmental change. These successions also contain evidence for syn-sedimentary faulting that has been related to the rifting of Rodinia, and in turn the tectonic context of the onset of Snowball Earth. These interpretations hinge on local geological relationships and both regional and global stratigraphic correlations. Here we present new geological mapping, measured stratigraphic sections, carbon and strontium isotope chemostratigraphy, and micropaleontology from the Neoproterozoic glacial deposits and bounding strata in Death Valley. These new data enable us to refine regional correlations both across Death Valley and throughout Laurentia, and construct a new age model for glaciogenic strata and microfossil assemblages. Particularly, our remapping of the Kingston Peak Formation in the Saddle Peak Hills and near the type locality shows for the first time that glacial deposits of both the Marinoan and Sturtian glaciations can be distinguished in southeastern Death Valley, and that beds containing vase-shaped microfossils are slump blocks derived from the underlying strata. These slump blocks are associated with multiple overlapping unconformities that developed during syn-sedimentary faulting, which is a common feature of Cyrogenian strata along the margin of Laurentia from California to Alaska. With these data, we conclude that all of the microfossils that have been described to date in Neoproterozoic strata of Death Valley predate the glaciations and do not bear on the severity, extent or duration of Neoproterozoic Snowball Earth events
Pressurized rf cavities in ionizing beams
A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf) test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF6 and O-2 were measured.ope
Charged kaon lifetime at KLOE
Preliminary result on the charged kaon lifetime, obtained by the KLOE
experiment operating at DANE, the Frascati -factory, is presentedComment: 3 pages, 3 figures, to appear in the proceedings of 42nd Rencontres
de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 10-17 Mar 200
Astrometry and geodesy with radio interferometry: experiments, models, results
Summarizes current status of radio interferometry at radio frequencies
between Earth-based receivers, for astrometric and geodetic applications.
Emphasizes theoretical models of VLBI observables that are required to extract
results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the
achievements of VLBI during the past two decades in reference frames, Earth
orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys.,
Vol. 70, Oct. 199
Measurements of the Absolute Branching Ratios for the Dominant KL Decays, the KL Lifetime, and Vus with the KLOE Detector
From a sample of about 10^9 Phi mesons produced at DAFNE, we have selected KL
mesons tagged by observing KS->pi+pi- decays. We present results on the major
KL branching ratios, including those of the semileptonic decays needed for the
determination of Vus. These branching ratio measurements are fully inclusive
with respect to final-state radiation. The KL lifetime has also been measured.Comment: Submitted to Phys. Lett.
A direct search for the CP-violating decay Ks->3p^0 with the KLOE detector at DAFNE
We have searched for the decay Ks->3p^0 with the KLOE experiment at DAFNE
using data from e^+ e^- collisions at a center of mass energy W= m(phi) for an
integrated luminosity L=450 pb^-1. The search has been performed with a pure Ks
beam obtained by tagging with Kl interactions in the calorimeter and detecting
six photons. We find an upper limit for the branching ratio of 1.2x10^-7 at 90%
C.L.Comment: 15 pages, 6 figures. To be submitted to Physics Letter
Measurement of the KL meson lifetime with the KLOE detector
We present a measurement of the KL lifetime using the KLOE detector. From a
sample of 4 x 10^8 KS KL pairs following the reaction e+ e- -> phi -> KS KL we
select 15 x 10^6 KL -> p0 p0 p0 decays tagged by KS -> pi+ pi- events. From a
fit of the proper time distribution we find tau_L = (50.92 +- 0.17{stat} +-
0.25{syst})$ ns. This is the most precise measurement of the KL lifetime
performed to date.Comment: 14 pages, 14 figure
Determination of CP and CPT violation parameters in the neutral kaon system using the Bell-Steinberger relation and data from the KLOE experiment
We present an improved determination of the CP and CPT violation parameters
Re(epsilon) and Im(delta) based on the unitarity condition (Bell-Steinberger
relation) and on recent results from the KLOE experiment. We find Re(epsilon) =
(159.6 \pm 1.3)10^-5 and Im(delta) = (0.4 \pm 2.1)10^-5, consistent with no CPT
violation.Comment: Submitted to JHE
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