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Search for b to u transitions in B- to [K+pi-pi0]_D K-

Description: The authors search for decays of a B meson into a neutral D meson and a kaon, with the D meson decaying into K{sup +}{pi}{sup -}{pi}{sup 0}. This final state can be reached through the b {yields} c transition B{sup -} {yields} D{sup 0}K{sup -} followed by the doubly Cabibbo-suppressed D{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}, or the b {yields} u transition B{sup -} {yields} {bar D}{sup 0}K{sup -} followed by the Cabibbo-favored {bar D}{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}. The interference of these two amplitudes is sensitive to the angle {gamma} of the unitarity triangle. They present preliminated results based on 226 x 10{sup 6} e{sup +}e{sup -} {yields} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at SLAC.
Date: December 6, 2006
Creator: Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y. et al.
Partner: UNT Libraries Government Documents Department

The Injection Laser System on the National Ignition Facility

Description: The National Ignition Facility (NIF) is currently the largest and most energetic laser system in the world. The main amplifiers are driven by the Injection Laser System comprised of the master oscillators, optical preamplifiers, temporal pulse shaping and spatial beam formatting elements and injection diagnostics. Starting with two fiber oscillators separated by up to a few angstroms, the pulse is phase modulated to suppress SBS and enhance spatial smoothing, amplified, split into 48 individual fibers, and then temporally shaped by an arbitrary waveform generator. Residual amplitude modulation induced in the preamplifiers from the phase modulation is also precompensated in the fiber portion of the system before it is injected into the 48 pre-amplifier modules (PAMs). Each of the PAMs amplifies the light from the 1 nJ fiber injection up to the multi-joule level in two stages. Between the two stages the pre-pulse is suppressed by 60 dB and the beam is spatially formatted to a square aperture with precompensation for the nonuniform gain profile of the main laser. The input sensor package is used to align the output of each PAM to the main laser and acquire energy, power, and spatial profiles for all shots. The beam transport sections split the beam from each PAM into four main laser beams (with optical isolation) forming the 192 beams of the NIF. Optical, electrical, and mechanical design considerations for long term reliability and availability will be discussed.
Date: December 13, 2006
Creator: Bowers, M; Burkhart, S; Cohen, S; Erbert, G; Heebner, J; Hermann, M et al.
Partner: UNT Libraries Government Documents Department

Comparative experimental study of x-ray absorption spectroscopy and electron energy loss spectroscopy on passivated U surfaces

Description: X-ray absorption spectroscopy and electron energy loss spectroscopy are complementary analytical techniques on energy and spatial resolution. These techniques are based on the same fundamental physical process of core excitation with either an incident photon or incident electron. In the proper experimental configuration the electron and photon inelastic scattering amplitudes are comparable and thus the x-ray and electron absorption edges look identical. We have applied these two complementary analytical techniques to investigate the electronic structure of C ion implanted U. Implantation of C{sup +} ions into U{sup 238} has been shown to produce a physically and chemically modified surface layer that passivates the surface preventing further air oxidation and corrosion. Comparison of the resultant spectra reveal that transitions between the initial state and a series of final states yield numerous strong features at the absorption edge that can provide structural information and information on the local chemical environment, including the character of the U 5f state.
Date: December 11, 2006
Creator: Nelson, A; Moberlychan, W; Bliss, R A; Siekhaus, W; Felter, T & Denliner, J
Partner: UNT Libraries Government Documents Department

Physics of reshock and mixing in single-mode Richtmyer-Meshkov instability

Description: The ninth-order weighted essentially non-oscillatory (WENO) shock-capturing method is used to investigate the physics of reshock and mixing in two-dimensional single-mode Richtmyer-Meshkov instability to late times. The initial conditions and computational domain were adapted from the Mach 1.21 air(acetone)/SF{sub 6} shock tube experiment of Collins and Jacobs [J. Fluid Mech. 464, 113 (2002)]: the growth of the bubble and spike perturbation amplitudes from fifth- and ninth-order WENO simulations of this experiment were compared to the predictions of amplitude growth models, and were shown to be in very good agreement with the experimental data prior to reshock [Latini, Schilling and Don, Phys. Fluids (2007), in press]. In the present investigation, the density, vorticity, baroclinic vorticity production, and simulated density Schlieren fields are first presented to qualitatively describe reshock. The baroclinic circulation deposition on the interface is shown to agree with the predictions of the Samtaney and Zabusky [J. Fluid Mech. 269, 45 (1994)] model and linear instability theory. The time-evolution of the positive and negative circulation on the interface is considered before and after reshock: it is shown that the circulations are equal before, as well as after reshock, until the interaction of the reflected rarefaction with the layer leads to flow symmetry breaking and different evolutions of the positive and negative circulation. The post-reshock mixing layer growth is shown to be in very good agreement with three models predicting linear growth for a short time following reshock. Next, a comprehensive investigation of local and global mixing properties as a function of time is performed. The distribution and amount of mixed fluid along the shock propagation direction is characterized using averaged mole fraction profiles, a fast kinetic reaction model, and molecular mixing fractions. The modal distribution of energy in the mixing layer is quantified using the spectra of the fluctuating kinetic ...
Date: December 13, 2006
Creator: Schilling, O; Latini, M & Don, W
Partner: UNT Libraries Government Documents Department

A Non-parametric approach to measuring the K- pi+ amplitudes in D+ ---> K- K+ pi+ decay

Description: Using a large sample of D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the K{sup -}{pi}{sup +} amplitudes in D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decay. The technique is similar to the technique used for our non-parametric measurements of the D{sup +} {yields} {bar K}*{sup 0} e{sup +}{nu} form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the {bar K}*{sub 0}{sup 0}(1430) contribution than the standard, PDG [1] Breit-Wigner parameterization. We have some weaker evidence for the existence of a new, D-wave component at low values of the K{sup -}{pi}{sup +} mass.
Date: December 1, 2006
Creator: Link, J.M.; Yager, P.M.; /UC, Davis; Anjos, J.C.; Bediaga, I.; Castromonte, C. et al.
Partner: UNT Libraries Government Documents Department

A non-parametric approach to measuring the k- pi+ amplitudes in d+ --> k- k+ pi+ decay

Description: Using a large sample of D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the K{sup -} {pi}{sup +} amplitudes in D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decay. The technique is similar to the technique used for our non-parametric measurements of the D{sup +} {yields} {bar K}*{sup 0} e{sup +}{nu} form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the {bar K}*{sub 0}{sup 0}(1430) contribution than the standard, PDG [1] Breit-Wigner parameterization. We have some weaker evidence for the existence of a new, D-wave component at low values of the K{sup -} {pi}{sup +} mass.
Date: December 1, 2006
Creator: Link, J.M.
Partner: UNT Libraries Government Documents Department

The Velocity Field of the Local Universe From Measurements of Type Ia Supernovae

Description: We present a measurement of the velocity flow of the local universe relative to the CMB rest frame, based on the Jha, Riess & Kirshner (2007) sample of 133 low redshift type Ia supernovae. At a depth of 4500 km s{sup -1} we find a dipole amplitude of 279 {+-} 68 km s{sup -1} in the direction l = 285{sup o} {+-} 18{sup o}, b = -10{sup o} {+-} 15{sup o}, consistent with earlier measurements and with the assumption that the local velocity field is dominated by the Great Attractor region. At a larger depth of 5900 km s{sup -1} we find a shift in the dipole direction towards the Shapley concentration. We also present the first measurement of the quadrupole term in the local velocity flow at these depths. Finally, we have performed detailed studies based on N-body simulations of the expected precision with which the lowest multipoles in the velocity field can be measured out to redshifts of order 0.1. Our mock catalogues are in good agreement with current observations, and demonstrate that our results are robust with respect to assumptions about the influence of local environment on the type Ia supernova rate.
Date: December 8, 2006
Creator: Haugbolle, T.; Hannestad, S.; Thomsen, B.; U., /Aarhus; Fynbo, J.; Inst., /Bohr et al.
Partner: UNT Libraries Government Documents Department