We present STAR measurements of the azimuthal anisotropyparameter v_2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi,and \Omega + bar Omega, along with v_4 for pions, kaons, protons, andLambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4and 200 GeV. The v_2(p_T) values for all hadron species at 62.4 GeV aresimilar to those observed in 130 and 200 GeV collisions. For observedkinematic ranges, v_2 values at 62.4, 130, and 200 GeV are as little as10 percent-15 percent larger than those in Pb+Pb collisions at sqrt s NN=17.3 GeV. At intermediate transverse momentum (p_T from 1.5-5 GeV/c),the 62.4 GeV v_2(p_T) and v_4(p_T) values are consistent with thequark-number scaling first observed at 200 GeV. A four-particle cumulantanalysis is used to assess the non-flow contributions to pions andprotons and some indications are found for a smaller non-flowcontribution to protons than pions. Baryon v_2 is larger than anti-baryonv_2 at 62.4 and 200 GeV perhaps indicating either that the initialspatial net-baryon distribution is anisotropic, that the mechanismleading to transport of baryon number from beam- to mid-rapidity enhancesv_2, or that anti-baryon and baryon annihilation is larger in thein-plane direction.

We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature compared to a pure Au hohlraum that is in agreement with predictions and is ascribable to reduced wall losses. This data suggests that a NIF ignition hohlraum made of a U:Au:Dy cocktail should have {approx}17% reduction in wall losses compared to a similar gold hohlraum.

An experimental investigation of the kink instability is presented in a linear plasma column where one end is line-tied to the plasma source, and the other end is not line-tied and therefore free to slide over the surface of the end-plate. This latter boundary condition is a result of plasma sheath resistance that insulates, at least partially, the plasma from the end-plate. The helical m = 1 kink mode is observed to grow when the plasma current exceeds a threshold and, close to the criticality, is characterized by an axial mode structure with maximum displacement at the free axial boundary. Azimuthal rotation of the mode is observed such that the helically kinked column always screws into the free axial boundary. The kink mode structure, rotation frequency and instability threshold are accurately reproduced by a recent kink theory [D. D. Ryutov, et al., Phys. Plasmas 13, 032105 (2006)], which includes axial plasma flow and one end of the plasma column that is free to move due to a perfect non-line-tying boundary condition which is experimentally verified. A brief review of the kink theory and its predictions for the boundary conditions relevant in the present experiments are presented.

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We present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay into the CP = +1 final state K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}, with K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -}. We use a sample of approximately 227 million B-meson pairs recorded at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B-Factory at SLAC. From an unbinned maximum likelihood fit we extract the mixing-induced CP-violation parameter S = 0.72 {+-} 0.71 {+-} 0.08 and the direct CP-violation parameter C = 0.23 {+-} 0.52 {+-} 0.13, where the first uncertainty is statistical and the second systematic.

Recent developments in multi-component Fe-based amorphous alloys have shown that these novel materials exhibit outstanding corrosion resistance compared to typical crystalline alloys such as high-performance stainless steels and Ni-based C-22 alloy. During the past decade, amorphous alloy synthesis has advanced to allow for the casting of bulk metallic glasses. In several Fe-based alloy systems it is possible to produce glasses with cooling rates as low as 100 K/s. At such low cooling rates, there is an opportunity to produce amorphous solids through industrial processes such as thermal spray-formed coatings. Moreover, since cooling rates in typical thermal spray processing exceed 1000 K/s, novel alloy compositions can be synthesized to maximize corrosion resistance (i.e. adding Cr and Mo) and to improve radiation compatibility (adding B) and still maintain glass forming ability. The applicability of Fe-based amorphous coatings in typical environments where corrosion resistance and thermal stability are critical issues has been examined in terms of amorphous phase stability and glass-forming ability through a coordinated computational analysis and experimental validation. For example, a wedge casting technique has been applied to examine bulk glass forming alloys by combining multiple thermal probes with a measurement based kinetics analysis and a computational thermodynamics evaluation to elucidate …

The blazar Markarian 501 (Mrk 501) was observed at energies above 100 GeV with the MAGIC telescope from May through July 2005. The high sensitivity of the instrument enabled the determination of the flux and spectrum of the source on a night-by-night basis. Throughout our observational campaign, the flux from Mrk 501 was found to vary by an order of magnitude, and to be correlated with spectral changes. Intra-night flux variability with flux-doubling times down to 2 minutes was also observed. The strength of variability increased with the energy of the {gamma}-ray photons. The energy spectra were found to harden significantly with increasing flux, and a spectral peak clearly showed up during very active states. The position of the spectral peak seems to be correlated with the source luminosity.

Volume independence in large N{sub c} gauge theories may be viewed as a generalized orbifold equivalence. The reduction to zero volume (or Eguchi-Kawai reduction) is a special case of this equivalence. So is temperature independence in confining phases. A natural generalization concerns volume independence in ''theory space'' of quiver gauge theories. In pure Yang-Mills theory, the failure of volume independence for sufficiently small volumes (at weak coupling) due to spontaneous breaking of center symmetry, together with its validity above a critical size, nicely illustrate the symmetry realization conditions which are both necessary and sufficient for large N{sub c} orbifold equivalence. The existence of a minimal size below which volume independence fails also applies to Yang-Mills theory with antisymmetric representation fermions [QCD(AS)]. However, in Yang-Mills theory with adjoint representation fermions [QCD(Adj)], endowed with periodic boundary conditions, volume independence remains valid down to arbitrarily small size. In sufficiently large volumes, QCD(Adj) and QCD(AS) have a large N{sub c} ''orientifold'' equivalence, provided charge conjugation symmetry is unbroken in the latter theory. Therefore, via a combined orbifold-orientifold mapping, a well-defined large N{sub c} equivalence exists between QCD(AS) in large, or infinite, volume and QCD(Adj) in arbitrarily small volume. Since asymptotically free gauge theories, such …

The B(E1;1/2{sup +}{yields} 1/2{sup -}) strength for {sup 11}Be has been extracted from intermediate energy Coulomb excitation measurements, over a range of beam energies using a new reaction model, the extended continuum discretized coupled channels (XCDCC) method. In addition, a measurement of the excitation cross section for {sup 11}Be+{sup 208}Pb at 38.6 MeV/nucleon is reported. The B(E1) strength of 0.105(12) e{sup 2}fm{sup 2} derived from this measurement is consistent with those made previously at 60 and 64 MeV/nucleon, in contrast to an anomalously low result obtained at 43 MeV/nucleon. By coupling a multi-configuration description of the projectile structure with realistic reaction theory, the XCDCC model provides for the first time a fully quantum mechanical description of Coulomb excitation. The XCDCC calculations reveal that the excitation process involves significant contributions from nuclear, continuum, and higher-order effects. An analysis of the present and two earlier intermediate energy measurements yields a combined B(E1) strength of 0.105(7) e{sup 2}fm{sup 2}. This value is in good agreement with the value deduced independently from the lifetime of the 1/2{sup -} state in {sup 11}Be, and has a comparable precision.

Rare charmless hadronic B decays are a good testing ground for the standard model. The dominant amplitudes contributing to this class of B decays are CKM suppressed tree diagrams and b {yields} s or b {yields} d loop diagrams (''penguins''). These decays can be used to study interfering standard model (SM) amplitudes and CP violation. They are sensitive to the presence of new particles in the loops, and they provide valuable information to constrain theoretical models of B decays. The B factories BABAR at SLAC and Belle at KEK produce B mesons in the reaction e{sup +}e{sup -} {yields} {Upsilon}(4S) {yields} B{bar B}. So far they have collected integrated luminosities of about 406 fb{sup -1} and 600 fb{sup -1}, respectively. The results presented here are based on subsets of about 200-500 fb{sup -1} and are preliminary unless a journal reference is given.

Metallic amorphous alloys or metallic glasses have been studied extensively for the last three decades due to their unique characteristics, including superior mechanical properties and corrosion resistance. Iron-based amorphous alloys have in general better corrosion resistance than their polycrystalline cousins such as the austenitic 18-8 stainless steel series (e.g. 316L SS). Fe-based amorphous alloys have even higher localized corrosion resistance than the nickel-based Alloy 22 under many laboratory tested conditions. Electrochemical laboratory tests have shown that when polycrystalline alloys such as Alloy 22 are anodically polarized in hot concentrated chloride brines, they dissolve unevenly following patterns associated with their crystalline character. However, amorphous alloys, when polarized to even higher potentials than the polycrystalline alloys, they dissolve in a desirable uniform manner. This is because the amorphous Fe-based alloys do not offer defects in the metal that can be preferentially attacked. Comparative studies will also be presented on the dissolution modes of Ni-gadolinium and borated stainless steels.

On November 22, 2005, the Manager of the Plutonium Finishing Plant (PFP) in Richland, WA issued an Occurrence Report involving a potential Pu-Fe eutectic failure mechanism for the stainless steel (SS) 3013 cans containing plutonium (Pu) metal. Four additional reports addressed nuclear safety concerns about the integrity of stainless steel containers holding plutonium during fire scenarios. The reports expressed a belief that the probability and consequences of container failure due to the formation of a plutonium-iron eutectic alloy had been overlooked. Simplified thermal model to address the Pu-Fe eutectic concerns using axisymmetric model similar to the models used in the 9975 SARP were performed. The model uses Rocky Flats configuration with 2 stacked Pu buttons inside a 3013 assembly. The assembly has an outer can, an inner can, and a convenience can, all stainless steel. The boundary conditions are similar to the regulatory 30 minutes HAC fire analyses. Computer simulations of the HAC fire transients lasting 4 hours of burn time show that the interface between the primary containment vessel and the Pu metal in the 9975 package will not reach Pu-Fe eutectic temperature of 400 C.

Conformal symmetry provides a systematic approximation to QCD in both its perturbative and nonperturbative domains. One can use the AdS/CFT correspondence between Anti-de Sitter space and conformal gauge theories to obtain an analytically tractable approximation to QCD in the regime where the QCD coupling is large and constant. For example, there is an exact correspondence between the fifth-dimensional coordinate of AdS space and a specific impact variable which measures the separation of the quark constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and allow the computation of exclusive scattering amplitudes. One can also use conformal symmetry as a template for perturbative QCD predictions where the effects of the nonzero beta function can be systematically included in the scale of the QCD coupling. This leads to fixing of the renormalization scale and commensurate scale relations which relate observables without scale or scheme ambiguity. The results are consistent with the renormalization group and the analytic connection of QCD to Abelian theory at N{sub C} {yields} 0. I also discuss a number of novel phenomenological features of QCD. Initial- …

Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 {micro}m and 8.0 {micro}m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B {approx} 170 {micro}G in spot A, and B {approx} 270 {micro}G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to {approx} 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of {approx} 1GeV. We argue that the shape of the …

Using BABAR measurements of the inclusive electron spectrum in B {yields} X{sub u}e{nu} decays and the inclusive photon spectrum in B {yields} X{sub s}{gamma} decays, we extract the magnitude of the CKM matrix element V{sub ub}. The extraction is based on several theoretical calculations designed to reduce the theoretical uncertainties by exploiting the assumption that the leading shape functions are the same for all b {yields} q transitions (q is a light quark). The current results agree well with the previous analysis, have indeed smaller theoretical errors, but are presently limited by the knowledge of the photon spectrum and the experimental errors on the lepton spectrum.

We present the first observation of the decay B{sup +} {yields} {rho}{sup +}K{sup 0}, using a data sample of 348 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector. The branching fraction and charge asymmetry are measured to be (8.0{sub -1.3}{sup +1.4} {+-} 0.5) x 10{sup -6} and (-12.2 {+-} 16.6 {+-} 2.0)%, respectively, where the first uncertainty is statistical and the second is systematic. The significance of the observed branching fraction, including systematic uncertainties, is 7.9 standard deviations.

Large scale InfiniBand clusters are becoming increasingly popular, as reflected by the TOP 500 Supercomputer rankings. At the same time, fat tree has become a popular interconnection topology for these clusters, since it allows multiple paths to be available in between a pair of nodes. However, even with fat tree, hot-spots may occur in the network depending upon the route configuration between end nodes and communication pattern(s) in the application. To make matters worse, the deterministic routing nature of InfiniBand limits the application from effective use of multiple paths transparently and avoid the hot-spots in the network. Simulation based studies for switches and adapters to implement congestion control have been proposed in the literature. However, these studies have focused on providing congestion control for the communication path, and not on utilizing multiple paths in the network for hot-spot avoidance. In this paper, we design an MPI functionality, which provides hot-spot avoidance for different communications, without a priori knowledge of the pattern. We leverage LMC (LID Mask Count) mechanism of InfiniBand to create multiple paths in the network and present the design issues (scheduling policies, selecting number of paths, scalability aspects) of our design. We implement our design and evaluate it …

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand the errors in shape measurements of astronomical objects, such as those used to study weak gravitational lensing of field galaxies. The PSF modeling involves either a Fourier transform of the phase information in the pupil plane or a ray-tracing approach, which has the advantage of requiring fewer computations than the Fourier transform. Using a standard method, involving the Gaussian weighted second moments of intensity, we then calculate the ellipticity of the PSF patterns. We find significant ellipticity for the instantaneous patterns (up to more than 10%). Longer exposures, which we approximate by combining multiple (N) images from uncorrelated atmospheric realizations, yield progressively lower ellipticity (as 1/{radical}N). We also verify that the measured ellipticity does not depend on the sampling interval in the pupil plane using the Fourier method. However, we find that the results using the ray-tracing technique do depend on the pupil sampling interval, representing a gradual breakdown of the geometric approximation at high spatial frequencies. Therefore, ray tracing is generally not an …

In a companion report, we have derived a method for finding the impedance at high frequencies of vacuum chamber transitions that are short compared to the catch-up distance, in a frequency regime that--in analogy to geometric optics for light--we call the optical regime. In this report we apply the method to various non-axisymmetric geometries such as irises/short collimators in a beam pipe, step-in transitions, step-out transitions, and more complicated transitions of practical importance. Most of our results are analytical, with a few given in terms of a simple one dimensional integral. Our results are compared to wakefield simulations with the time-domain, finite-difference program ECHO, and excellent agreement is found.

It is well known that an activity expansion of the grand canonical partition function works well for attractive interactions, but works poorly for repulsive interactions, such as occur between atoms and molecules. The virial expansion of the canonical partition function shows just the opposite behavior. This poses a problem for applications that involve both types of interactions, such as occur in the outer layers of low-mass stars. We show that it is possible to obtain expansions for repulsive systems that convert the poorly performing Mayer activity expansion into a series of rational polynomials that converge uniformly to the virial expansion. In the current work we limit our discussion to the second virial approximation. In contrast to the Mayer activity expansion the activity expansion presented herein converges for both attractive and repulsive systems.

This paper presents a feasibility study to improve thermal loading of existing radioactive material packages by using heat pipes. The concept could be used to channel heat in certain directions and dissipate to the environment. The concept is applied to a drum type package because the drum type packages are stored and transported in an upright position. This orientation is suitable for heat pipe operation that could facilitate the heat pipe implementation in the existing well proven package designs or in new designs where thermal loading is high. In this position, heat pipes utilize gravity very effectively to enhance heat flow in the upward direction Heat pipes have extremely high effective thermal conductivity that is several magnitudes higher than the most heat conducting metals. In addition, heat pipes are highly unidirectional so that the effective conductivity for heat transfer in the reverse direction is greatly reduced. The concept is applied to the 9977 package that is currently going through the DOE certification review. The paper presents computer simulations using typical off-the-shelf heat pipe available configurations and performance data for the 9977 package. A path forward is outlined for implementing the concepts for further study and prototype testing.

Iron-based amorphous alloys are desirable for many industrial applications due to their dual capacity to resist corrosion and wear. These alloys may also contain a significant amount of boron which makes them candidates for criticality control, for example, in high-level nuclear waste disposition applications. The Fe-based amorphous alloys can be produced in powder form and then deposited using a HVOF thermal spray process on any surface that needs to be protected. For the current testing coupons of 316L stainless steels were coated with the amorphous alloy SAM2X5 and then tested for corrosion resistance in the salt-fog chamber and in other industrial environments. Prototype cylinders were also prepared and environmentally tested. One cylinder was 30-inch diameter, 88-inch long, and 3/8-inch thick. The coating thickness was 0.015 to 0.019-inch thick. The cylinder was in good condition after the test. Along the body of the cylinder only two pinpoint spot sized signs of rust were seen. Test results will be compared with the behavior of witness materials under the same tested conditions.

The authors present measurements of the time-dependent CP-violating asymmetries in B{sup 0} {yields} K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0} decays based on 384 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. They obtain the CP asymmetry parameters C = 0.02 {+-} 0.21 {+-} 0.05 and S = -0.71 {+-} 0.24 {+-} 0.04, where the first uncertainties are statistical and the second systematic. These results are consistent with standard model expectations.

We report a measurement of CP-violating asymmetries in B{sup 0} {yields} ({rho}{pi}){sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0} decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 375 million {Upsilon}(4S) {yields} B{bar B} decays, collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure 26 coefficients of the bilinear form-factor terms occurring in the time-dependent decay rate of the B{sup 0} meson. We derive the physically relevant quantities from these coefficients. In particular, we measure a constraint on the angle {alpha} of the Unitarity Triangle.