We study B+ → π+π0π0 using 711 fb-1 of data collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Here we measure an inclusive branching fraction of ...(19.0 ±1.5 ±1.4)×10-6 and an inclusive CP asymmetry of (9.2 ±6.8 ±0.7)%, where the first uncertainties are statistical and the second are systematic, and a B+ → ρ(770)+π0 branching fraction of (11.2 ± 1.1 ± 0.9 $^{+0.8}_{-1.6}$)× 10-6, where the third uncertainty is due to possible interference with B+ → ρ(1450)+π0. We present the first observation of a structure around 1 GeV/c2 in the π0π0 mass spectrum, with a significance of 6.4σ, and measure a branching fraction to be (6.9 ±0.9 ±0.6) × 10-6. We also report a measurement of local CP asymmetry in this structure.
Using 980 fb−1 of data collected with the Belle detector operating at the KEKB asymmetric-energy e+ e− collider, we report the measurements of the masses, and the first measurements of the instrinsic ...widths, of the Σc ( 2455 )+ and Σc (2520)+ charmed baryons. We find M (Σc (2455)+) − M (Λc+) = 166.17 ± 0.0 5−0.07+0.16 MeV / c2, Γ (Σc (2455)+) = 2.3 ± 0.3 ± 0.3 MeV /c2, M ( Σc (2520)+) − M(Λc+) = 230.9 ± 0. 5− 0.1+ 0.5 MeV / c2, and Γ(Σc (2520)+) = 17.2− 2.1− 0.7+2.3+3.1 MeV / c2, where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the Σc states.
In sharp contrast to previous studies on FeRh bulk, thin films, and nanoparticles, we report the persistence of ferromagnetic order down to 3 K for size-selected 3.3 nm diameter nanocrystals embedded ...into an amorphous carbon matrix. The annealed nanoparticles have a B2 structure with alternating atomic Fe and Rh layers. X-ray magnetic dichroism and superconducting quantum interference device measurements demonstrate ferromagnetic alignment of the Fe and Rh magnetic moments of 3 and 1μ(B), respectively. The ferromagnetic order is ascribed to the finite-size induced structural relaxation observed in extended x-ray absorption spectroscopy.
The Zr-Cu-Al bulk glassy (BG) alloy, which has amorphous structure, possesses various properties such as high strength and toughness with compositional dependence. In the present study, density, ...positron annihilation lifetime and coincidence Doppler Broadening measurement have been performed for various compositional hyper-eutectic Zr-Cu-Al BG alloys. The density of hyper-eutectic Zr-Cu-Al BG alloys increases with decreasing of Zr fraction. In contrast, positron lifetime for all compositional alloys is almost constant about 165 psec. In addition, the CDB ratio profile is almost the same for hyper-eutectic alloys. This unchanging trend of CDB ratio profile is quite different from that of hypo-eutectic BG alloys. These results reveal that different internal structure exists in hyper and hypo-eutectic BG alloys.
Nanoporous Ta2O5 films with oriented and elongated nanopores have been prepared by a technique which utilizes the accumulation of free volume during the crystallization of amorphous Ta2O5 annealed ...above 973K. The transmission electron microscopy analyses revealed that voids were elongated in the 100 direction perpendicular to the longitudinal b axis of the orthorhombic structure. The self-assembly of a significant amount of oriented nanovoids can be contributed to the strong anisotropic crystal structure of orthorhombic Ta2O5.
The effect of pressure applied by hot isostatic press (HIP) on microstructure evolution during diffusion bonding was studied using a couple composed of an Fe–Al alloy (Fe–Al) and CrMo steel (CrMo). ...Columnar grains are formed from the joint interface to the CrMo side irrespective of pressure application. The average length of the columnar grains of the couple bonded with pressure was shorter than that of the couple bonded without pressure. For the couple bonded with pressure, the microstructure of the CrMo side beyond the columnar grains exhibits fine facets with acicular precipitates of Fe
3C. Further, strong hardening is found in this region. The application of pressure retards the aluminum diffusion from Fe–Al to CrMo. The growth rate of the columnar grain with respect to bonding time deviated from the parabolic law. These effects of the pressure application on the microstructure evolution are due to the suppression of aluminum diffusion and retardation of transformation during bonding.
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