Search for CP violation in the decay B0-->D*+/-D-/+

We report a search for CP-violating asymmetry in B0-->D(*+/-)D-/+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D(*+)-->D0pi(+)(slow) decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.     

Aggregation states and surface wettability in films of poly(styrene-block-2-perfluorooctyl ethyl acrylate) diblock copolymers synthesized by atom transfer radical polymerization

Well-defined poly(styrene-block-2-perfluorooctyl ethyl acrylate) [P(St-b-PFA)] copolymers with various chemical compositions were synthesized by atom transfer radical polymerization. Films of P(St-b-PFA) were structurally characterized, from bulk to surface, on the basis of transmittance electron microscopic observation and small-angle X-ray scattering, X-ray photoelectron spectroscopic, and contact angle measurements. For a comparison, poly(styrene-random-2-perfluorooctyl ethyl acrylate) [P(St-ran-PFA)] copolymers were also synthesized by conventional free radical polymerization. While P(St-b-PFA) with the 2-perfluorooctyl ethyl acrylate (PFA) content higher than 18.7 mol % formed a typical phase-separated cylinder structure, P(St-b-PFA) with a lower PFA content and P(St-ran-PFA) were in a miscible state. Since the perfluoroalkyl groups possess extremely low surface energy, they were preferentially segregated at the film surface, resulting in the formation of the PFA surface layer. This was the case for all P(St-b-PFA) films examined, although the aggregation state at the surface was strongly dependent on the PFA content. In the case of the P(St-b-PFA) with the PFA content higher than 18.7 mol %, both advancing and receding contact angles for water were 120 degrees and even larger with almost no hysteresis. In addition, extremely excellent oil-repellent surface properties such as advancing and receding contact angles for dodecane of 76 degrees and 75 degrees were also observed. However, these intriguing liquid-repellent properties were not observed for the films of miscible P(St-b-PFA) and P(St-ran-PFA). Therefore, it can be concluded that the internal structure beneath the surface as well as the surface itself should be deeply considered to design excellent and stable liquid-repellent materials.     

In situ observation of single polymers adsorbed onto mica surfaces in water

The morphology of a cationic polymer of high molecular weight, poly[2-(acryloyloxy)ethyl(trimethyl)ammoniumchloride], adsorbed on to a mica surface in water was observed in situ using the tapping mode of an atomic force microscope with a high-resolution probe. It was found that the morphology of adsorbed polymers changes with time to be lumplike, floclike, and then fibril-like and that it takes surprisingly a long time for the polymers to relax completely in water, even though they are highly charged. Detailed structures of extended polymers are also discussed.     

Observation of radiative B-->phi K gamma decays

The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB.     

The first samarium(II)-mediated aryl radical cyclisation onto an aromatic ring

Intramolecular arylation of aryl radicals was mediated by SmI(2)/HMPA in the presence of i-PrOH to give spirocycles and/or reduced cine-cyclised products, while the reaction in the absence of i-PrOH gave the rearomatised fused rings.     

Measurement of branching fractions for B-->eta(c)K(*) decays

We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB.     

Adsorption of thiolates to singly coordinated sites on Au111 evidenced by photoelectron diffraction

The adsorption structure of methylthiolate (CH3S) adsorbed on Au(111), a long-standing controversial issue, has been unambiguously determined by scanned-energy and scanned-angle S 2p photoelectron diffraction. The methylthiolate molecules are found to occupy atop sites with a S-Au distance of 2.42 +/- 0.03 A. The angular distribution of the S 2p photoelectrons due to forward scattering reveals that the S-C bond is inclined by approximately 50 degrees from the surface normal towards both the [211] and [121] (nearest-neighbor thiolate) directions.     

Polarization-mode dispersion measurement by an optical time-domain reflectometer with polarimetry assuming backscattering by randomly oriented nonspherical particles

In previous work on polarization-mode dispersion (PMD) measurement with an optical time-domain reflectometer with polarimetry (p-OTDR), scatterers were assumed to be a cloud of small spherical particles in a fiber. We have found that the p-OTDR waveforms were fitted well by modified Mueller matrices, assuming scattering by a cloud of nonspherical particles. We realized a PMD measurement based on the p-OTDR Jones matrix eigenanalysis (JME) method. The measured PMD was consistent with that of JME standard measurement with transmission-type polarimetry.     

Improved direct measurement of the parity-violation parameter Ab using a mass tag and momentum-weighted track charge

We present an improved direct measurement of the parity-violation parameter A(b) in the Z boson-b-quark coupling using a self-calibrating track-charge technique applied to a sample enriched in Z-->bb events via the topological reconstruction of the B hadron mass. Manipulation of the Stanford Linear Collider electron-beam polarization permits the measurement of A(b) to be made independently of other Z-pole coupling parameters. From the 1996-1998 sample of 400,000 hadronic Z decays, produced with an average beam polarization of 73.4%, we find A(b)=0.906+/-0.022(stat)+/-0.023(syst).     

Recoil-limited laser cooling of 87Sr atoms near the Fermi temperature

A dynamic magneto-optical trap, which relies on the rapid randomization of population in Zeeman substates, has been demonstrated for fermionic strontium atoms on the 1S0-3P1 intercombination transition. The obtained sample, 1x10(6) atoms at a temperature of 2 microK in the trap, was further Doppler cooled and polarized in a far-off resonant optical lattice to achieve 2 times the Fermi temperature.