Shock initiation experiments on the explosives Composition B and C-4 were performed to obtain in-situ pressure gauge data for the purpose of providing the Ignition and Growth reactive flow model with proper modeling parameters. A 100 mm diameter propellant driven gas gun was utilized to initiate the explosive charges containing manganin piezoresistive pressure gauge packages embedded in the explosive sample. Experimental data provided new information on the shock velocity--particle velocity relationship for each of the investigated material in their respective pressure range. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data, and Ignition and Growth modeling calculations resulted in a good fit to the experimental data. Identical ignition and growth reaction rate parameters were used for C-4 and Composition B, and the Composition B model also included a third reaction rate to simulate the completion of reaction by the TNT component. This model can be applied to shock initiation scenarios that have not or cannot be tested experimentally with a high level of confidence in its predictions.

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Direct imaging of extrasolar planets is an important, but challenging, next step in planetary science. Most planets identified to date have been detected indirectly--not by emitted or reflected light but through the effect of the planet on the parent star. For example, radial velocity techniques measure the doppler shift in the spectrum of the star produced by the presence of a planet. Indirect techniques only probe about 15% of the orbital parameter space of our solar system. Direct methods would probe new parameter space, and the detected light can be analyzed spectroscopically, providing new information about detected planets. High contrast adaptive optics systems, also known as Extreme Adaptive Optics (ExAO), will require contrasts of between 10{sup -6} and 10{sup -7} at angles of 4-24 {lambda}/D on an 8-m class telescope to image young Jupiter-like planets still warm with the heat of formation. Contrast is defined as the intensity ratio of the dark wings of the image, where a planet might be, to the bright core of the star. Such instruments will be technically challenging, requiring high order adaptive optics with > 2000 actuators and improved diffraction suppression. Contrast is ultimately limited by residual static wavefront errors, so an extrasolar planet …

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A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is being developed as a compact flash x-ray radiography source. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be presented.

Precise collimation of the beam halo is required in the International Linear Collider (ILC) to prevent beam losses near the interaction region that could cause unacceptable backgrounds for the physics detector. The necessarily small apertures of the collimators lead to transverse wakefields that may result in beam deflections and increased emittance. A set of collimator wakefield measurements has previously been performed in the ASSET region of the SLAC Linac. We report on the next phase of this program, which is carried out at the recently commissioned End Station A (ESA) test facility at SLAC. Measurements of resistive and geometric wakefields using tapered collimators are compared with model predictions from MAFIA and GdfidL and with analytic calculations.

We report preliminary measurements of the exclusive charmless semileptonic branching fractions of the B{sup +} {yields} {eta}{ell}{sup +}{nu} and B{sup +} {yields} {eta}'{ell}{sup +}{nu} decays. These measurements are based on 316 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the BABAR detector. In events in which the decay of one B meson to a hadronic final state is fully reconstructed, the semileptonic decay of the recoiling B meson is identified by the detection of a charged lepton and an {eta} or {eta}'. We measure the branching fraction {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) = (0.84 {+-} 0.27 {+-} 0.21) x 10{sup -4}, where the first error is statistical and the second one systematic. We also set an upper limit on the branching fraction of {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) < 1.4 x 10{sup -4} and {Beta}(B{sup +} {yields} {eta}'{ell}{sup +}{nu}) < 1.3 x 10{sup -4} at the 90% confidence level.

CP violation in B{sup 0}{bar B}{sup 0} mixing is characterized by the value of the parameter |q/p| being different from 1, and the Standard Model predicts this difference to be smaller than 10{sup -3}. We present a measurement of this parameter using a partial reconstruction of one of the B mesons in the semileptonic channel D*{sup -}{ell}{sup +}{nu}{sub {ell}}, where only the hard lepton and the soft pion from the D*{sup -} {yields} {bar D}{sup 0}{pi}{sup -} decay are reconstructed. The flavor of the other B is determined by means of lepton tagging. The determination of |q/p| is then performed with a fit to the proper time difference of the two B decays. We use a luminosity of 200.8 fb{sup -1}, collected at the {Upsilon}(4S) resonance by the BABAR detector at the PEP-II asymmetrical-energy e{sup +}e{sup -} collider, in the period 1999-2004. We obtain the preliminary result: |q/p| - 1 = (6.5 {+-} 3.4(stat.) {+-} 2.0(syst.)) {center_dot} 10{sup -3}.

Understanding the quantum efficiency (QE) of a metal photocathode in an s-band RF gun is important to limit the drive laser energy requirement and provide the best quality electron beam. Systematic measurements of the qe vs. wavelength for varying surface contamination have been performed on copper samples using x-ray photoelectron spectroscopy (XPS). The sample is first cleaned to the theoretical limit of QE using a 1 keV hydrogen ion beam. The H-ion beam cleans an area approximately 1cm in diameter and has no effect on the surface roughness while removing essentially all contaminants and lowering the work function to 4.3eV[1]. The sample is then exposed to atmospheric contaminants (nitrogen and oxygen) and measured again with XPS to determine the degree of contamination and their effect on the QE. These results and comparison with theory are presented.

In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 {micro}m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus …

In this paper we revisit the topological twisted sigma model with H-flux. We explicitly expand and then twist the worldsheet Lagrangian for bi-Hermitian geometry. we show that the resulting action consists of a BRST exact term and pullback terms, which only depend on one of the two generalized complex structures and the B-field. We then discuss the topological feature of the model.

The deformation of the microscopic, pure metal grains (0.1 to > 1 millimeter) in the copper cells of accelerator structures decreases the power handling capabilities of the structures. The extent of deformation caused by mechanical fabrication damage is the focus of this study. Scanning electron microscope (SEM) imaging of a bonded test stack of six accelerating cells at magnifications of 30, 100, 1000 were taken before simulated mechanical damage was done. After a 2{sup o}-3{sup o} twist was manually applied to the test stack, the cells were cut apart and SEM imaged separately at the same set magnifications (30, 100, and 1000), to examine any effects of the mechanical stress. Images of the cells after the twist were compared to the images of the stack end (cell 60) before the twist. Despite immense radial damage to the end cell from the process of twisting, SEM imaging showed no change in grain morphology from images taken before the damage: copper grains retained shape and the voids at the grain boundaries stay put. Likewise, the inner cells of the test stack showed similar grain consistency to that of the end cell before the twist was applied. Hence, there is no mechanical deformation …

We perform the first three-dimensional measurement of the amplitudes of B {yields} {psi}(2S)K* and B {yields} {chi}{sub c1}K* decays and update our previous measurement for B {yields} J/{psi} K*. We use a data sample collected with the BABAR detector at the PEP-II storage ring, representing 232 million produced B{bar B} pairs. The longitudinal polarization of decays to the 1{sup ++} {chi}{sub c1} meson together with a K* meson, is found to be larger than that for the decay to the 1{sup --} {Psi} mesons. No direct CP-violating charge asymmetry is observed.

Experiments at the FLASH linac at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the down mix and digitizing electronics are straightforward, similar to those for a conventional BPM.

The authors present an updated measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0} decays based on 347 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The authors obtain the CP asymmetries S{sub f} = -0.66 {+-} 0.26 {+-} 0.08 and C{sub f} = -0.14 {+-} 0.22 {+-} 0.05, where the first uncertainties are statistical and the second systematic.

The authors report first observations of the decays B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{pi}{sup -}, using 292 fb{sup -1} of data collected at the {Upsilon}(4S) resonance energy by the BABAR detector at the PEP-II e{sup +}e{sup -} collider. The branching fractions are measured to be {Beta}(B{sup -} {yields} D{sub s}{sup +}K{sup -}{pi}{sup -}) = (1.88 {+-} 0.13 {+-} 0.41) {center_dot} 10{sup -4} and {Beta}(B{sup -} {yields} D{sub s}{sup *+}K{sup -}{pi}{sup -}) = (1.84 {+-} 0.19 {+-} 0.40) {center_dot} 10{sup -4}.

String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.

We consider a scalar field, such as the Higgs boson H, coupled to gluons via the effective operator H tr G{sub {mu}{nu}} G{sup {mu}{nu}} induced by a heavy-quark loop. We treat H as the real part of a complex field {phi} which couples to the self-dual part of the gluon field-strength, via the operator {phi} tr G{sub SD {mu}{nu}} G{sub SD}{sup {mu}{nu}}, whereas the conjugate field {phi} couples to the anti-self-dual part. There are three infinite sequences of amplitudes coupling {phi} to quarks and gluons that vanish at tree level, and hence are finite at one loop, in the QCD coupling. Using on-shell recursion relations, we find compact expressions for these three sequences of amplitudes and discuss their analytic properties.

We present a study of two states decaying to {Lambda}{sub c}{sup +} K{sup -} {pi}{sup +} using the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} storage rings. We use an integrated luminosity of 288.5 fb{sup -1} collected at the center-of-mass energy {radical}s = 10.58 GeV, near the peak of the {Upsilon}(4S) resonance, plus 27.2 fb{sup -1} collected approximately 40MeV below this energy. We search for the particles {Xi}{sub c}(2980){sup +} and {Xi}{sub c}(3077){sup +}, recently discovered by the Belle Collaboration, in their decays to {Lambda}{sub c}{sup +}K{sup -}{pi}{sup +}, where {Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +}. We find a signal with 7.0{sigma} significance for the {Xi}{sub c}(2980){sup +} state with a mass difference with respect to the {Lambda}{sub c}{sup +} of (680.6 {+-} 1.9 {+-} 1.0)MeV/c{sup 2} (first error is statistical and second error is systematic). The measured width for this state is (23.6 {+-} 2.8 {+-} 1.3)MeV, and the yield is 284 {+-} 45 {+-} 46 events. We find a signal with 8.6{sigma} significance for the {Xi}{sub c}(3077){sup +} state with a mass difference with respect to the {Lambda}{sub c}{sup +} of (790.0 {+-} 0.7 {+-} 0.2) MeV/c{sup 2}, a width of (6.2 {+-} 1.6 …