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301 - 325 of 924
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CreatorTitleDescriptionSubjectDate
301 Gondolo, PaoloHalo independent comparison of direct dark matter detection dataWe extend the halo-independent method of Fox, Liu, and Weiner to include energy resolution and efficiency with arbitrary energy dependence, making it more suitable for experiments to use in pre-senting their results. Then we compare measurements and upper limits on the direct detection of low mass (...2012-01-01
302 DeTar, CarletonHeavy-light decay constants - MILC results with the Wilson actionWe present the current status of our ongoing calculations of pseudoscalar meson decay constants for mesons that contain one light and one heavy quark (fB, fBs , fD, fDs ). We are currently generating new gauge configurations that include dynamical quarks and calculating the decay constants. In add...Decay constants; Wilson action; Kogut-Susskind quarks; Staggered quarks; Chiral extrapolation1998-01
303 DeTar, CarletonHeavy-light decay constants using clover valence quarks and three flavors of dynamical improved staggered quarksStarting in 2001, the MILC Collaboration began a large scale calculation of heavy-light meson decay constants using clover valence quarks on ensembles of three flavor configurations. For the coarse configurations, with a = 0.12 fm, eight combinations of dynamical light and strange quarks have been ...Decay constants; Clover valence quarks; Staggered quarks2005-03
304 DeTar, CarletonHeavy-light decay constants with dynamical gauge configurations and Wilson or improved valence quark actionsWe describe a calculation of heavy-light decay constants including virtual quark loop effects. We have generated dynamical gauge configurations at three _x000C_ values using two flavors of Kogut-Susskind quarks with a range of masses. These are analyzed with a Wilson valence quark action. Prelimin...Decay constants; Kogut-Susskind quarks; Wilson quarks; Fat-clover valence quarks2000-04
305 DeTar, CarletonHeavy-light decay constants with three dynamical flavorsWe present preliminary results for the heavy-light leptonic decay constants in the presence of three light dynamical flavors. We generate dynamical configurations with improved staggered and gauge actions and analyze them for heavy-light physics with tadpole improved clover valence quarks. When th...Leptonic decay; Decay constants2002-03
306 DeTar, CarletonHeavy-light decay constants: conclusions from the Wilson actionWe report on the results of a MILC collaboration calculation of fB, fBs , fD, fDs and their ratios. We discuss the most important errors in more detail than we have elsewhere.Decay constants; Wilson action; Staggered quarks1999-03
307 DeTar, CarletonHeavy-light meson decay constants with N f = 3During the past year the MILC Collaboration has continued its study of heavy-light meson decay constants with three dynamical quarks. Calculations have been extended to a second lattice spacing of about 0.09 fm. At this lattice spacing, there are results in the quenched approximation and for thr...Dynamical quarks2003-05
308 Wu, Yong-ShiHidden massive Dirac fermions in effective field theory for integral quantum Hall transitionsIntegral quantum Hall plateau transitions in a planar lattice system due to gap collapse can be described by an effective field theory with Dirac fermions. We discuss how to reproduce the correct integral values for the Hall conductance sxy before and after the plateau transition, which are dictat...Dirac fermions; Vorticities; Edge states; Hall conductance1996-08
309 Sokolsky, PierreHigh Resolution Fly's Eye - status and preliminary results on cosmic ray composition above 10^18 eVWe describe the current status of the High Resolution Fly's Eye detector. Event reconstruction and associated systematics for stereo reconstruction are discussed and recent preliminary results on the study of the composition of ultra-high energy cosmic rays by the Xmax method are presented. These r...Ultra-high energy cosmic rays; Fluorescence; Stereo detection2002
310 Symko, Orest GeorgeHigh Tc rf-biased SQUIDResults are presented on the behavior of a simple rf-biased SQUID made out of YBa2Cu307. It consists of a fractured ceramic pellet stuck together at room temperature. This simple device is shielded by a high Tc tube and it shows the characteristic flux quantization behavior up to 77K. At 4.2K its ma...High Tc RF-biased SQUID1989-03
311 Kieda, David B.High resolution charge measurements of UH cosmic ray nuclei using a direct imaging Cherenkov ground-based observatoryThe accurate determination of the elemental composition of cosmic rays at high energies is expected to provide crucial clues on the origin of these particles. Here we discuss a technique that has become possible through the use of modern ground-based Cherenkov imaging detectors. We combine a measure...Cherenkov light; Quark star; UH nuclei; Magnetic monopole2003
312 Williams, Clayton C.High resolution photothermal laser probeAt frequencies near 1 GHz, the acoustic wavelength in argon gas becomes half that of visible light, making possible collinear Bragg scattering of laser light by the sound. This acousto-optic interaction has been used to detect photothermally generated acoustic power at the surface of solids. This ne...Photothermal laser probe; Silicon wafer1984
313 Williams, Clayton C.High resolution thermal microscopyA new high resolution thermal microscope has been demonstrated capable of imaging thermal fields with sub 1000 angstom resolution. It is based upon a non-contacting near field thermal probe. The thermal probe consists of a thermocouple sensor on the end of a tip with sub 1000 angstrom dimensions. Th...1986
314 Ailion, David CharlesHigh sensitivity nuclear quadrupole resonance approach for detection of modulation wave motion in incommensurate systemsIn contrast to conventional NMR techniques that use magnetic field gradients (MFCs) to detect the diffusion of moving atoms, we have developed a highly sensitive approach for detecting electric field gradient (EFG) fluctuations seen by stationary atoms. These EFG fluctuations were observed in the ...NMR; MFG; Magnetic field gradients; Diffusion constants; Atoms; Nuclei1995
315 Kieda, David B.High statistics search for ultrahigh energy gamma-ray emission from Cygnus X-3 and Hercules X-1We have carried out a high statistics (2 X 10 9 events) search for ultrahigh energy g-ray emission from the x-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990-1995), we find no evidence for steady emission from either source. T...Cygnus X-3; Hercules X-1; Ultrahigh energy; X-rays1997
316 DeTar, CarletonHigh-precision lattice QCD confronts experimentThe recently developed Symanzik-improved staggered-quark discretization allows unquenched lattice-QCD simulations with much smaller (and more realistic) quark masses than previously possible. To test this formalism, we compare experiment with a variety of nonperturbative calculations in QCD draw...Staggered quarks2004-01
317 Wu, Yong-ShiHigh-precision quasienergies for a driven two-level atom at the two-photon preresonanceA computation with unprecedented precision is presented for quasienergies of a two-level atom in a monochromatic radiation on the basis of a recently obtained exact expression [D.-S. Guo et al., Phys. Rev. A 73,023419 (2006)]. We start with the proof of an expression theorem. With this theorem the ...Quasienergies; Preresonance; Floquet periodicity2008-02
318 Vardeny, Zeev ValentineHigh-pressure effects on ultrafast-relaxation kinetics of excitons in polydiacetylene 4BCMUUltrafast-relaxation kinetics of the singlet excitons in polydiacetylene 4BCMU was measured at hydrostatic pressures up to 80 kbar, using the pump-probe photoinduced-absorption technique with 70-fs resolution at 2 eV and 5 ps in the spectral range 1.2-2.2 eV. The 100-fs decay component survives at...Ultrafast-relaxation; Polydiacetylene 4BCMU; Pi-conjugated polymers; Quasi-1D excitations1991-05
319 Vardeny, Zeev ValentineHigh-pressure study of picosecond exciton dynamics in solid C60We have studied the singlet exciton decay by picosecond photoinduced absorption in films of Qo, under pressures up to 62 kbar. The picosecond decay of excitons excited in the absorption tail continues to be dominated by broad distributions of lifetimes at high pressure. These results suggest that th...Picosecond exciton dynamics; Solid C601994-08
320 Williams, Clayton C.High-resolution photothermal laser probeAn advance in photothermal imaging is described. A photothermal laser probe is presented that operates at a frequency of 1 GHz. At this frequency the spacial resolution is limited only by the optical spot size of the probe beam. The photothermal sensitivity of the probe is 1.2 X 10-4 degrees Celsiu...Laser probes1985
321 Dawson, KyleHigh-voltage-compatible fully depleted CCDsWe describe charge-coupled device (CCD) development activities at the Lawrence Berkeley National Laboratory (LBNL). Back-illuminated CCDs fabricated on 200-300 fxm thick, fully depleted, high-resistivity silicon substrates are produced in partnership with a commercial CCD foundry. The CCDs are full...Large Synoptic Survey Telescope; X-ray emission; XMM22352006
322 Sokolsky, PierreHighest energy cosmic rays and results from the HiRes experimentThe status of the field of ultrahigh energy cosmic ray physics is summarized, from the point of view of the latest results of the High Resolution Fly's Eye (HiRes) Experiment. HiRes results are presented, and compared with those of the Akeno Giant Air Shower Array (AGASA), plus the Telescope Array ...Fluorescence; Energy spectrum; GZK cutoff; Extensive air showers; Anisotropy2007-11-01
323 Sokolsky, PierreHighest-energy cosmic raysWhat in the cosmos can possibly be accelerating protons to 1020 electron volts and beyond? And how can they preserve such extreme energies while plowing through the cosmic microwave background on their way to us?Energy spectrum; GZK cutoff; Atmospheric fluorescence1998
324 Wu, Yong-ShiHolography and noncommutative Yang-Mills theoryIn this Letter a recently proposed gravity dual of noncommutative Yang-Mills theory is derived from the relations between closed string moduli and open string moduli recently suggested by Seiberg and Witten. The only new input one needs is a simple form of the running string tension as a function ...Noncommutativity; String theory; Gravity dual2000-03
325 Vardeny, Zeev ValentineHot-carrier thermalization in amorphous siliconThermalization of photoinduced carriers in a-Si and α-Si:H was studied with use of sub-picosecond-pump and probe techniques with parallel and perpendicular polarizations. The underlying process was identified as hot-carrier absorption whose cross section increases with the carrier excess energy. T...Amorphous silicon; Thermalization; Photoinduced carriers; Frohlich interaction1981-05
301 - 325 of 924