A Triassic to Cretaceous Sundaland–Pacific subduction margin in West Sarawak, Borneo

Metamorphic rocks in West Sarawak are poorly exposed and studied. They were previously assumed to be pre-Carboniferous basement but had never been dated. New 40Ar/39Ar ages from white mica in quartz-mica schists reveal metamorphism between c. 216 to 220 Ma. The metamorphic rocks are associated with Triassic acid and basic igneous rocks, which indicate widespread magmatism. New U-Pb dating of zircons from the Jagoi Granodiorite indicates Triassic magmatism at c. 208 Ma and c. 240 Ma. U-Pb dating of zircons from volcaniclastic sediments of the Sadong and Kuching Formations confirms contemporaneous volcanism. The magmatic activity is interpreted to represent a Triassic subduction margin in westernmost West Sarawak with sediments deposited in a forearc basin derived from the magmatic arc at the Sundaland–Pacific margin. West Sarawak and NW Kalimantan are underlain by continental crust that was already part of Sundaland or accreted to Sundaland in the Triassic. One metabasite sample, also previously assumed to be pre-Carboniferous basement, yielded Early Cretaceous 40Ar/39Ar ages. They are interpreted to indicate resumption of subduction which led to deposition of volcaniclastic sediments and widespread magmatism. U-Pb ages from detrital zircons in the Cretaceous Pedawan Formation are similar to those from the Schwaner granites of NW Kalimantan, and the Pedawan Formation is interpreted as part of a Cretaceous forearc basin containing material eroded from a magmatic arc that extended from Vietnam to west Borneo. The youngest U-Pb ages from zircons in a tuff layer from the uppermost part of the Pedawan Formation indicate that volcanic activity continued until c. 86 to 88 Ma when subduction terminated

Progressive internal gravity waves with bounded upper surface climbing a triangular obstacle

In this paper we discuss a theoretical model for the interfacial profiles of progressive non-linear waves which result from introducing a triangular obstacle, of finite height, attached to the bottom below the flow of a stratified, ideal, two layer fluid, bounded from above by a rigid boundary. The derived equations are solved by using a nonlinear perturbation method. The dependence of the interfacial profile on the triangular obstacle size, as well as its dependence on some flow parameters, such as the ratios of depths and densities of the two fluids, have been studied

The atmospheric implications of radiation belt remediation

High altitude nuclear explosions (HANEs) and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR). Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections

Prospects for the Measurement of the Higgs Yukawa Couplings to b and c quarks, and muons at CLIC

The investigation of the properties of the Higgs boson, especially a test of the predicted linear dependence of the branching ratios on the mass of the final state is going to be an integral part of the physics program at colliders at the energy frontier for the foreseeable future. The large Higgs boson production cross section at a 3TeV CLIC machine allows for a precision measurement of the Higgs branching ratios. The cross section times branching ratio of the decays H->bb, H->cc and H->{\mu}{\mu} of a Standard Model Higgs boson with a mass of 120 GeV can be measured with a statistical uncertainty of 0.23%, 3.1% and 15%, respectively, assuming an integrated luminosity of 2 ab-1.Comment: 6 pages, 4 figure

A Bayesian technique for improving the sensitivity of the atmospheric neutrino L/E analysis

This paper outlines a method for improving the precision of atmospheric neutrino oscillation measurements. One experimental signature for these oscillations is an observed deficit in the rate of $\nu_{\mu}$ charged-current interactions with an oscillatory dependence on $L_{\nu}/E_{\nu}$, where $L_{\nu}$ is the neutrino propagation distance, and $E_{\nu}$ is the neutrino energy. For contained-vertex atmospheric neutrino interactions, the $L_{\nu}/E_{\nu}$ resolution varies significantly from event to event. The precision of the oscillation measurement can be improved by incorporating information on $L_{\nu}/E_{\nu}$ resolution into the oscillation analysis. In the analysis presented here, a Bayesian technique is used to estimate the $L_{\nu}/E_{\nu}$ resolution of observed atmospheric neutrinos on an event-by-event basis. By separating the events into bins of $L_{\nu}/E_{\nu}$ resolution in the oscillation analysis, a significant improvement in oscillation sensitivity can be achieved.Comment: 12 pages, 7 figures, submitted to Nucl. Instrum. Methods A, accompanies arXiv:1208.2915 [hep-ex

Evaluation of measurement accuracies of the Higgs boson branching fractions in the International Linear Collider

Precise measurement of Higgs boson couplings is an important task for International Linear Collider (ILC) experiments and will facilitate the understanding of the particle mass generation mechanism. In this study, the measurement accuracies of the Higgs boson branching fractions to the $b$ and $c$ quarks and gluons, $\Delta Br(H\to b\bar{b},\sim c\bar{c},\sim gg)/Br$, were evaluated with the full International Large Detector model (\texttt{ILD\_00}) for the Higgs mass of 120 GeV at the center-of-mass (CM) energies of 250 and 350 GeV using neutrino, hadronic and leptonic channels and assuming an integrated luminosity of $250 {\rm fb^{-1}}$, and an electron (positron) beam polarization of -80% (+30%). We obtained the following measurement accuracies of the Higgs cross section times branching fraction ($\Delta (\sigma \cdot Br)/\sigma \cdot Br$) for decay of the Higgs into $b\bar{b}$, $c\bar{c}$, and $gg$; as 1.0%, 6.9%, and 8.5% at a CM energy of 250 GeV and 1.0%, 6.2%, and 7.3% at 350 GeV, respectively. After the measurement accuracy of the cross section ($\Delta\sigma/\sigma$) was corrected using the results of studies at 250 GeV and their extrapolation to 350 GeV, the derived measurement accuracies of the branching fractions ($\Delta Br/Br$) to $b\bar{b}$, $c\bar{c}$, and gg were 2.7%, 7.3%, and 8.9% at a CM energy of 250 GeV and 3.6%, 7.2%, and 8.1% at 350 GeV, respectively.Comment: 15 pages, 6 figure

Neutrino mean free paths in spin-polarized neutron Fermi liquids

Neutrino mean free paths in magnetized neutron matter are calculated using the Hartree-Fock approximation with effective Skyrme and Gogny forces in the framework of the Landau Fermi Liquid Theory. It is shown that describing nuclear interaction with Skyrme forces and for magnetic field strengths $log_{10} B(G) \gtrsim 17$, the neutrino mean free paths stay almost unchanged at intermediate densities but they largely increase at high densities when they are compared to the field-free case results. However the description with Gogny forces differs from the previous and mean free paths stay almonst unchanged or decrease at densities $[1-2]\rho_0$. This different behaviour can be explained due to the combination of common mild variation of the Landau parameters with both types of forces and the values of the nucleon effective mass and induced magnetization of matter under presence of a strong magnetic field as described with the two parametrizations of the nuclear interaction.Comment: 9 pages, 3 figure

A Beta Beam complex based on the machine upgrades for the LHC

The Beta Beam CERN design is based on the present LHC injection complex and its physics reach is mainly limited by the maximum rigidity of the SPS. In fact, some of the scenarios for the machine upgrades of the LHC, particularly the construction of a fast cycling 1 TeV injector (``Super-SPS''), are very synergic with the construction of a higher $\gamma$ Beta Beam. At the energies that can be reached by this machine, we demonstrate that dense calorimeters can already be used for the detection of $\nu$ at the far location. Even at moderate masses (40 kton) as the ones imposed by the use of existing underground halls at Gran Sasso, the CP reach is very large for any value of $\theta_{13}$ that would provide evidence of $\nu_e$ appearance at T2K or NO$\nu$A ($\theta_{13}\geq 3^\circ$). Exploitation of matter effects at the CERN to Gran Sasso distance provides sensitivity to the neutrino mass hierarchy in significant areas of the $\theta_{13}-\delta$ plane

A Measurement of Time-Averaged Aerosol Optical Depth using Air-Showers Observed in Stereo by HiRes

Air fluorescence measurements of cosmic ray energy must be corrected for attenuation of the atmosphere. In this paper we show that the air-showers themselves can yield a measurement of the aerosol attenuation in terms of optical depth, time-averaged over extended periods. Although the technique lacks statistical power to make the critical hourly measurements that only specialized active instruments can achieve, we note the technique does not depend on absolute calibration of the detector hardware, and requires no additional equipment beyond the fluorescence detectors that observe the air showers. This paper describes the technique, and presents results based on analysis of 1258 air-showers observed in stereo by the High Resolution Fly's Eye over a four year span.Comment: 7 pages, 3 figures, accepted for publication by Astroparticle Physics Journa