Effect of Fabry‐Perot resonances in disordered one‐dimensional array of alternating dielectric bi‐layers

We study numerically and analytically the role of Fabry‐Perot resonances in the transmission through a one‐dimensional finite array formed by two alternating dielectric slabs. The disorder consists in varying randomly the width of one type of layers while keeping constant the width of the other type. Our numerical simulations show that localization is strongly inhibited in a wide neighborhood of the Fabry‐Perot resonances. Comparison of our numerical results with an analytical expression for the average transmission, derived for weak disorder and finite number of cells, reveals that such expression works well even for medium disorder up to a certain frequency. Our results are valid for photonic and phononic one‐dimensional disordered crystals, as well as for semiconductor superlattices.     

Search for Kaluza-Klein graviton emission in pp collisions at square root[s] = 1.8 TeV using the missing energy signature

We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb(-1) of ppmacr; collisions at sqrt[s]=1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a (3+1+n)-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for n=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.     

Inclusive double-pomeron exchange at the fermilab tevatron p p collider

We report results from a study of events with a double-Pomeron exchange topology produced in p p collisions at sqrt[s]=1800 GeV. The events are characterized by a leading antiproton and a large rapidity gap on the outgoing proton side. We find that the differential production cross section agrees in shape with predictions based on Regge theory and factorization, and that the ratio of double-Pomeron exchange to single diffractive production rates is relatively unsuppressed as compared to the O(10) suppression factor previously measured in single diffractive production.     

Reactions induced by 35 MeV 6He beam on 12C and 14C

The ⁶He+^12,14C scattering and reactions have been studied using a 35 MeV ⁶He radioactive beam and preliminary results are presented. The three-body reaction ⁶He+¹²C ↦ ¹⁰Be+2 α has been clearly identified and sequential decay of intermediate states in ¹⁴C has been studied. Search for an analog reaction on ¹⁴C, ⁶He+¹⁴C ↦ ¹²Be+2 α, has not given conclusive results yet. Other interesting reactions with this entrance channel are discussed.     

Measurement of the lifetime difference between Bs mass eigenstates

We present measurements of the lifetimes and polarization amplitudes for B(0)(s)-->J/psiphi and B(0)(d)-->J/psiK(*0) decays. Lifetimes of the heavy and light mass eigenstates in the B(0)(s) system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203+/-15 B(0)(s) decays we obtain tau(L) = (1.05(+0.16)(-0.13) +/- 0.02) ps and tau(H) = (2.07(+0.58)(-0.46) +/- 0.03) ps. Expressed in terms of the difference DeltaGamma(s) and average Gamma(s), of the decay rates of the two eigenstates, the results are DeltaGamma(s)/Gamma(s) = (65(+25)(-33) +/- 1)% and DeltaGamma(s) = (0.47(+0.19)(-0.24) +/- 0.01) ps(-1).     

Search for new high-mass particles decaying to Lepton pairs in pp collisions at square root s = 1.96 TeV

A search for new particles (X) that decay to electron or muon pairs has been performed using approximately 200 pb(-1) of pp collision data at (square root) s = 1.96 TeV collected by the CDF II experiment at the Fermilab Tevatron. Limits on sigma(pp --> X)BR (X --> ll) are presented as a function of dilepton invariant mass m(ll) > 150 GeV/c2, for different spin hypotheses (0, 1, or 2). The limits are approximately 25 fb for m(ll) > GeV/c2. Lower mass bounds for X from representative models beyond the standard model including heavy neutral gauge bosons are presented.     

Measurement of the W(+)W(-) production cross section in pp collisions at square root[s]=1.96 TeV using dilepton events

We present a measurement of the W(+)W(-) production cross section using 184 pb(-1) of p(p) collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W(+)W(-)-->l(+)nul(-), where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0(+2.2)(-0.8) events. The resulting W(+)W(-) production cross-section measurement of sigma(pp-->W(+)W(-))=14.6(+5.8)(-5.1)(stat)(+1.8)(-3.0)(syst) +/- 0.9(lum) pb agrees well with the standard model expectation.     

Upsilon production and polarization in p p macro collisions at square root of s = 1.8 TeV

We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections (d(2)sigma/dp(T)dy)(/y/<0.4), as well as on the Upsilon(1S) polarization in p p macro collisions at square root of s = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Upsilon-->mu(+)mu(-). The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production.     

Preparation and characterization of the Na4UO2(O2)3·8H2O complex

The Na₄UO₂(O₂)₃·8H₂O complex was prepared from aqueous systems and its crystallographic and chemical structural conformation characterized. IR spectroscopy and X-ray diffraction were used for analyzing the solid crystal extracted with ethanol to determine the anionic compositon. Composition of the solid phase did not depend on the molar ratio of the reactants or on the pH of the medium, but only upon the absolute concentrations of uranium and alkali. It was observed that the temperature significantly influenced the crystal structure of the product and that a limit to the UO₂ concentration existed for inducing the production of a mixture of soluble and insoluble species.     

Note on an airfoil in a slightly non-uniform stream

Summary An investigation is presented of the modifications that must be made to two-dimensional calculations of the flow past an airfoil when the flow takes place in a symmetric channel with slightly non-parallel walls.