Search for doubly charged higgs boson pair production in the decay to mu(+)mu(+)mu(-)mu(-) in pp collisions at sqrt[s]=1.96 TeV

A search for pair production of doubly charged Higgs bosons in the process pp -->H(++)H(--) -->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of sqrt[s]=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H(+/-+/-)(L))>118.4 GeV/c(2) and M(H(+/-+/-)(R))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs.     

Electron-induced neutron knockout from 4He

The differential cross section for electron-induced neutron knockout in the reaction 4He(e,e(')n)(3)He has been measured for the first time with a statistical accuracy of 11%. The experiment was performed in quasielastic kinematics at a momentum transfer of 300 MeV/c and in the missing-momentum range of 25-70 MeV/c. The comparison of the data with theoretical calculations shows an impressive increase of the cross section resulting from final state interaction effects. Specifically, the p-n charge-exchange process dominates the cross section in this kinematical regime.     

Improved direct measurement of A(b) and A(c) at the Z(0) pole using a lepton tag

The parity violation parameters A(b) and A(c) of the Zb(b) and Zc(c) couplings have been measured directly, using the polar angle dependence of the polarized cross sections at the Z(0) pole. Bottom and charmed hadrons were tagged via their semileptonic decays. Both the electron and muon analyses take advantage of new multivariate techniques to increase the analyzing power. Based on the 1993-1998 SLD sample of 550,000 Z(0) decays produced with highly polarized electron beams, we measure A(b) = 0.919+/-0.030(stat)+/-0.024(syst), and A(c) = 0.583+/-0.055(stat)+/-0.055(syst).     

Study of B0 --> J/psiK(*)0pi(+)pi(-) decays with the collider detector at Fermilab

We report a study of the decays B0 --> J/psiK(*)0pi(+)pi(-), which involve the creation of a uu or dd quark pair in addition to a b -->c(cs) decay. The data sample consists of 110 pb(-1) of pp collisions at square root[s] = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching fractions to be B(B0 --> J/psiK(*0)pi(+)pi(-)) = (6.6 +/- 1.9 +/- 1.1)x10(-4) and B(B0 --> J/psiK0pi(+)pi(-)) = (10.3 +/- 3.3 +/- 1.5)x10(-4). Evidence is seen for contributions from psi(2S)K(*)0, J/psiK0rho(0), J/psiK(*+)pi(-), and J/psiK1(1270).     

Coherent Hall effect in a semiconductor superlattice

The coherent Hall effect denotes the transient Hall response of impulsively excited coherent charge-carrier wave packets in a solid. We report the first experimental study of this phenomenon (i) using a semiconductor superlattice in crossed electric and magnetic fields as a model for three-dimensional materials and (ii) employing a contactless optoelectronic technique to probe the transient currents. Two field regimes with distinctly different oscillatory wave packet dynamics are found, separated from each other by a transition region where all oscillations are suppressed.     

Surface Enhanced Resonance of Metal Nano Clusters: A Novel Tool for Proteomics

A novel nano-tool based on metal clusters enables the transduction of changes of biorecognitive binding as well as conformation quantitatively into an optical signal which can be observed directly as a color change of a sensor-chip surface.Proteins including various enzymes and serum proteins were spotted via micro-arraying onto the chip surface forming monolayer and thin film dots. Multi-layered (up to 300 nm thick) nano-gel-pads were stabilized by photo crosslinking the protein dots with UV-light. By deposition of metal-nano clusters, synthesized via chemical means or sputter coating on top of photo-crosslinked macromolecules an optical resonance effect was obtained.The response of the novel surface enhanced absorption cluster sensor-chip was transduced spectroscopically in the visible and IR range of the spectrum via an 8 m resolution reflectance scanner.     

Double diffraction dissociation at the Fermilab Tevatron collider

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.     

Behavior of transversally isotropic cylindrical shells under dynamic application of radial pressure

We consider the problem on the buckling of a transversally isotropic long cylindrical shell under dynamic external pressure. For the cases of a sudden load [1] and a load rapidly increasing with time [2], we compare the results obtained from the two-dimensional Kirchhoff-Love and Timoshenko-Reissner theories.     

High-field EPR studies on polymer film formation from colloidal dispersions

High-field EPR on nitroxide spin probes is applied to characterize the dynamics of small additive molecules and surfactants in polymer films obtained from colloidal dispersions. Due to the increased width of the spectra and the smaller influence of hyperfine-dependent relaxation on the spectral lineshape at W band (94 GHz) compared to X band (9.6 GHz), it is possible to measure subnanosecond rotational correlation times for the isotropic motion of the unpolar spin probe TEMPO in the free volume of poly(acrylate) films. Likewise, the anisotropies of the rotational diffusion tensors of a surfactant and a small ionic additive molecule in poly(fluoroacrylate) films can be determined with better confidence at W band. From these anisotropies it is concluded that the surfactant aggregates exhibit low molecular order, whereas the ionic additives are strongly attached to immobilized ionic clusters. High-field EPR lineshapes at W band are also found to be more sensitive to slow motions on a microsecond time scale than X-band EPR lineshapes. The design of a Fabry-Pérot resonator for measurements on polymer films is discussed and its sensitivity is demonstrated on a wet polymer film with a thickness of 160 μm.