Production of WZ events in pp collisions at square root(s) = 1.96 TeV and limits on anomalous WWZ couplings

We present results from a search for WZ production with subsequent decay to l nu l' l' (l and l' = e or mu) using 0.30 fb(-1) of data collected by the D0 experiment between 2002 and 2004 at the Fermilab Tevatron. Three events with WZ decay characteristics are observed. With an estimated background of 0.71 +/- 0.08 events, we measure the WZ production cross section to be 4.5(-2.6)(+3.8) pb, with a 95% C.L. upper limit of 13.3 pb. The 95% C.L. limits for anomalous WWZ couplings are found to be -2.0 < delta kappaZ < 2.4 for form factor scale lambda = 1 TeV, and -0.48 < lambdaZ < 0.48 and -0.49 < delta g(1)(Z) < 0.66 for lambda = 1.5 TeV.     

Atomic-scale phase coexistence and fluctuation at the quasi-one-dimensional metal-insulator transition

Scanning tunneling microscopy of a quasi-one-dimensional (1D) metal-insulator transition in an In nanowire array on the Si(111) surface reveals unprecedented details in the transition dynamics. The transition proceeds in microscopic first order, namely, through the domain-by-domain conversion at the nanoscale, from the metallic to the insulating phase or vice versa. The definition of domains and their effective transition temperatures (Tc) are strongly correlated with the distribution of defects. Below Tc, the condensation and the fluctuation of 1D charge density waves are observed within the isolated metallic domains, as well as at the domain boundaries. The appearance of such isolated condensates suggests a strong intrawire coupling: a manifestation of the 1D nature of the critical fluctuation, as well as the origin of the first-order transition.     

Measurement of inclusive differential cross sections for pp collisions at (square root)s = 1.96 TeV

We present measurements of the inclusive production cross sections of the Gamma(1S) bottomonium state in pp collisions at (square root)s = 1.96 TeV. Using the Gamma(1S) --> mu(+)mu(-) decay mode for a data sample of 159 +/- 10 pb(-1) collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Gamma(1S) transverse momentum for three ranges of the Gamma(1S) rapidity: 0 < y(Gamma) < or = 0.6, 0.6 < y(Gamma) < or = 1.2, and 1.2 < y(Gamma) < or = 1.8.     

Measurement of the ratio of B+ and B0 meson lifetimes

The ratio of the B+ and B0 meson lifetimes was measured using data collected in 2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider. These mesons were reconstructed in B-->mu(+)nuD(*-)X decays, which are dominated by B0 and B-->mu(+)nuD 0X decays, which are dominated by B+. The ratio of lifetimes is measured to be tau(+)/tau(0)=1.080+/-0.016(stat)+/-0.014(syst).     

Search for anomalous heavy-flavor quark production in association with W bosons

We search for anomalous production of heavy-flavor quark jets in association with W bosons at the Fermilab Tevatron pp Collider in final states in which the heavy-flavor quark content is enhanced by requiring at least one tagged jet in an event. Jets are tagged using one algorithm based on semileptonic decays of b/c hadrons, and another on their lifetimes. We compare e+jets (164 pb(-1)) and mu+jets (145 pb(-1)) channels collected with the D0 detector at sqrt[s]=1.96 TeV to expectations from the standard model and set upper limits on anomalous production of such events.     

Measurement of the B0s lifetime in the exclusive decay channel B0s-->J/psiphi

Using the exclusive decay B0s-->J/psi(mu+mu-)phi(K+K-), we report the most precise single measurement of the B0s lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb(-1) collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the B0s lifetime, tau(B0s)=1.444(+0.098)(-0.090)(stat)+/-0.020(sys) ps. We also report a measurement for the lifetime of the B0 meson using the exclusive decay B0-->J/psi(mu+mu-)K*0(892)(K+pi-). We reconstruct 1370 signal candidates, obtaining tau(B0)=1.473(+0.052)(-0.050)(stat)+/-0.023(sys) ps, and the ratio of lifetimes, tau(B0s)/tau(B0)=0.980(+0.076)(-0.071)(stat)+/-0.003(sys).     

Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.     

Experimental demonstration of 10 Gbit/s transmission with an optical backplane system using optical slots

A practical optical backplane system was prepared with transmitter-receiver processing boards and an optical backplane made from polymeric-waveguide-embedded optical printed-circuit boards. Optical slots were used as connection components between the transmitter-receiver processing boards and the backplane board to permit easy and repeatable insertion and extraction of the boards with micrometer precision. We report 10 Gbit/s data transmission between an optical backplane and the transmitter-receiver processing boards.     

Isospin projected FBCS wavefunction for light nuclei

Two equivalent isospin projection methods are proposed and applied to a conventional FBCS wavefunction, thus obtaining a F _NT BCS one. To test the effect of the projection the FBCS and F _NT BCS wavefunctions are compared with an exact shell model one. Practical calculations are carried out for He⁶ using the Volkov's semi-realistic potential and the first 3 major shells. Results of the calculations show that a) the F _NT BCS with 5 free parameters is capable of approximating the shell model wavefunction with 87 parameters and b) the FBCS results differ little from the F _NT BCS ones in this special case, what should be caused by the Pauli principle and the large energy spacing ?ω.