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[[abstract]]High-purity (97%) samples of 27-Å phase of Y-Ba-Cu-O have been prepared in superconducting thin films on (100) SrTiO3. The possibility that the observed superconductivity might arise from a residual 3% Ba2YCu3O7 impurity in this sample is ruled out using transmission electron microscopy which shows that it is present only as isolated particles. This allows for an unambiguous determination that the 27-Å phase is superconducting with an onset Tc of 82 K and Tc(R=0) of 79 K.
[[abstract]]In this paper, we present a Ga2O3(Gd2O3)/Si3N4 dual-layer gate dielectric approach for III-V MOSFETs application. This dual-layer dielectric was formed by first depositing a Ga2O3(Gd2O3) layer in-situ on In0.18Ga0.82As. This unpins the In0.18Ga0.82As surface Fermi-level. Then an nm-thick Molecular-and-Atomic Deposition (MAD) of Si3N4 was ex-situ deposited on Ga2O3(Gd2O3), protecting Ga2O3(Gd2O3) from moisture during air-exposure and device processing. We fabricated and characterized n-channel depletion-mode and enhancement mode MOSFETs on In0.18Ga0.82As, with a total effective oxide thickness (EOT) of ~ 5 nm. Depletion-mode MOSFET with a ring gate of L=10 £gm and large S/D to gate separation of 12.5 ?Ým exhibits Id of 6mA/mm at Vds=4V and Vg=1V. We also demonstrate an enhancement mode MOSFET with surface channel inversion t...
[[abstract]]The magnetic structures of several single‐crystal, magnetic rare‐earth superlattice systems grown by molecular‐beam epitaxy are reviewed. In particular, the results of recent neutron diffraction investigations of long‐range magnetic order in Gd‐Y, Dy‐Y, Gd‐Dy, and Ho‐Y periodic superlattices are presented. In the Gd‐Y system, an antiphase domain structure develops for certain Y layer spacings, whereas modified helical moment configurations are found to occur in the other systems, some of which are commensurate with the chemical superlattice wavelength. References are made to theoretical interaction mechanisms recently proposed to account for the magnetic states of these novel materials.
Results of a detailed study of strange particle production in neutrino neutral current interactions are presented using the data from the NOMAD experiment. Integral yields of neutral strange particles (K0s, Lambda, Lambda-bar) have been measured. Decays of resonances and heavy hyperons with an identified K0s or Lambda in the final state have been analyzed. Clear signals corresponding to K* and Sigma(1385) have been observed. First results on the measurements of the Lambda polarization in neutral current interactions have been obtained.
First measurements of K*(892) mesons production properties and their spin alignment in nu_mu charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For K*+ and K*- mesons produced in nu_mu CC interactions and decaying into K0 pi+/- we have found the following yields per event: (2.6 +/- 0.2 (stat.) +/- 0.2 (syst.))% and (1.6 +/- 0.1 (stat.) +/- 0.1 (syst.))% respectively, while for the K*+ and K*- mesons produced in nu NC interactions the corresponding yields per event are: (2.5 +/- 0.3 (stat.) +/- 0.3 (syst.))% and (1.0 +/- 0.3 (stat.) +/- 0.2 (syst.))%. The results obtained for the rho00 parameter, 0.40 +/- 0.06 (stat) +/- 0.03 (syst) and 0.28 +/- 0.07 (stat) +/- 0.03 (syst) for K*+ and K*- produced in nu_mu CC ...
We report updated branching fraction measurements of the color-suppressed decays B0bar to D0 pi0, D*0 pi0, D0 eta, D*0 eta, D0 omega, D*0 omega, D0 eta_prime, and D*0 eta_prime. We measure the branching fractions (*10^-4): BF(B0bar to D0 pi0) = 2.69 +/- 0.09 +/- 0.13, BF(B0bar to D*0 pi0) = 3.05 +/- 0.14 +/- 0.28, BF(B0bar to D0 eta) = 2.53 +/- 0.09 +/- 0.11, BF(B0bar to D*0 eta) = 2.69 +/- 0.14 +/- 0.23, BF(B0bar to D0 omega) = 2.57 +/- 0.11 +/- 0.14, BF(B0bar to D*0 omega) = 4.55 +/- 0.24 +/- 0.39, BF(B0bar to D0 eta_prime) = 1.48 +/- 0.13 +/- 0.07,and BF(B0bar to D*0 eta_prime) = 1.49 +/- 0.22 +/- 0.15. We also present the first measurement of the longitudinal polarization fraction of the decay channel D*0 omega, f_L = (66.5+/- 4.7+/- 1.5) %. In the above, the first uncertainty is statistical and the second is systematic. The result...
We report a search for CP violation in the decay \tau- -> \pi - \K^0_S (>= 0 \pi 0) \nu_\tau\ using a dataset of 437 million \tau\ lepton pairs, corresponding to an integrated luminosity of 476 fb^{-1}, collected with the BABAR detector at the PEP-II asymmetric energy e+e- storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.45 +/- 0.24 +/- 0.11)%, approximately three standard deviations from the Standard Model prediction of (0.33 +/- 0.01)%.
We report a measurement of the inclusive semileptonic branching fraction of the B_s meson using data collected with the BaBar detector in the center-of-mass (CM) energy region above the Upsilon(4S) resonance. We use the inclusive yield of phi mesons and the phi yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B_s mesons relative to all B mesons as a function of CM energy. The inclusive semileptonic branching fraction of the B_s meson is determined to be B(B_s to l nu X)=9.5 (+2.5/-2.0)(stat)(+1.1/-1.9)(syst)%, where l indicates the average of e and mu.
We search for hadronic decays of a light Higgs boson (A0) produced in radiative decays of an Upsilon(2S) or Upsilon(3S) meson, Upsilon --> gamma A0. The data have been recorded by the BABAR experiment at the Upsilon(3S) and Upsilon(2S) center of mass energies, and include (121.3 \pm 1.2) x 10^6 Upsilon(3S) and (98.3 \pm 0.9) x 10^6 Upsilon(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions B(Upsilon(nS)-->gamma A0) x B(A0-->hadrons) (n=2 or 3) that range from 1 x 10^{-6} for an A0 mass of 0.3 GeV/c^2 to 8 x 10^{-5} at 7 GeV/c^2.
We present searches for rare or forbidden charm decays of the form $X_c^+\to h^\pm\ell^\mp\ell^{(\prime)+}$, where $X_c^+$ is a charm hadron ($D^+$, $D^+_s$, or $\Lambda_c^+$), $h^\pm$ is a pion, kaon, or proton, and $\ell^{(\prime)\pm}$ is an electron or muon. The analysis is based on $384 fb^{-1}$ of $e^+e^-$ annihilation data collected at or close to the $\Upsilon(4S)$ resonance with the BaBar detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the 35 decay modes that are investigated. We establish 90% confidence-level upper limits on the branching fractions between $1 \times 10^{-6}$ and $44 \times 10^{-6}$ depending on the channel. In most cases, these results represent either the first limits or significant improvements on existing limits for the decay modes studied.
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