Nuclear orientation study of low temperature magnetization of54Mn impurity in ferromagnetic PtFe alloys

Low-temperature nuclear orientation of⁵⁴Mn in ferromagnetic Pt₉₅Fe₅ and Pt₉₀Fe₁₀ hosts has been investigated in 12–50 mK temperature range at external magnetic fields up to 1.2 T. Temperature dependence of the effective magnetic field B_eff on Mn has been observed and interpreted as an effect of misalignment of Mn magnetic moments with respect to the macroscopic magnetization direction at host magnetic saturation.     

Fluctuation of rare-earth atom magnetic moments in superconducting ceramics (Ho,Er)-Ba-Cu-O studied by μSR

Zero field muon spin relaxation measurements of the ceramic high-T_c superconductors HoBa₂Cu₃O_7-σ, O_c≃93 K) and ErBa₂Cu₃O_7-σ (T_c≃95 K) reveal the sharp difference between the behaviours of the muon spin relaxation rate at temperatures below 20K. This fact may be explained by assumption that the frequency of fluctuations of Er magnetic moments exceeds by far the fluctuation frequency of Ho in 1-2-3 compounds.     

Measurement of the CP asymmetry in B-->Xs gamma

Direct CP violation in the b-->sgamma process is a sensitive probe of physics beyond the standard model. We report a measurement of the CP asymmetry in B-->X(s)gamma, where the hadronic recoil system X(s) is reconstructed using a pseudoreconstruction technique. In this approach there is negligible contamination from b-->dgamma decays, which are expected to have a much larger CP asymmetry. We find A(CP)=0.002+/-0.050(stat)+/-0.030(syst) for B-->X(s)gamma events having recoil mass smaller than 2.1 GeV/c(2). The analysis is based on a data sample of 140 fb(-1) recorded at the upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring.     

Measurement of /V(ub)/ using inclusive B-->X(u)lnu decays with a novel X(u)-reconstruction method

We report the measurement of an inclusive partial branching fraction for charmless semileptonic B decay and the extraction of /V(ub)/. Candidates for B-->X(u)lnu are identified with a novel X(u) reconstruction method based on neutrino reconstruction via missing 4-momentum and a technique called "simulated annealing." Based on 86.9 fb(-1) of data taken with the Belle detector, we obtain DeltaB(B-->X(u)lnu;M(X)<1.7 GeV/c2,q2>8.0 GeV2/c2)=[7.37+/-0.89(stat)+/-1.12(syst)+/-0.55(b-->c)+/-0.24(b-->u)]x10(-4) and determine |V(ub)|=[4.66+/-0.28(stat)+/-0.35(syst)+/-0.17(b-->c)+/-0.08(b-->u)+/-0.58(theory)]x10(-3).     

Observation of B0-->D*sJ(2317)+K- decay

The decays B0-->D+sJK- and B0-->D-sJpi+ are studied for the first time. A significant signal is observed in the B0-->D*sJ(2317)+K- decay channel with B(B0-->D*sJ(2317)+K-) x B(D*sJ(2317)+-->D+spi0)=(5.3(+1.5)(-1.3)+/-0.7+/-1.4) x 10(-5). No signals are observed in the B0-->D*sJ(2317)-pi+, B0-->DsJ(2460)+K-, and B 0-->DsJ(2460)-pi+ decay modes, and upper limits are obtained. The analysis is based on a data set of 140 fb(-1) collected by the Belle experiment at the asymmetric e+e- collider KEKB.     

Studies of CP violation in B-->J/PsiK* decays

CP violation in B-->J/PsiK* decays is studied using an angular analysis in a data sample of 253 fb(-1) recorded with the Belle detector at the KEKB e(+)e(-) collider. The flavor separated measurements of the decay amplitudes indicate no evidence for direct CP violation. T-odd CP violation is studied using the asymmetries in triple product correlations, and the results are consistent with the standard model null predictions. The time-dependent angular analysis gives the following values of CP-violating parameters: sin(2phi(1) = 0.24 +/- 0.31 +/- 0.05 and cos(2phi(1)=0.56 +/- 0.79 +/- 0.11.     

Long-range assemblies on poly(dG-dC)2 and poly(dA-dT)2: phosphonium cationic porphyrins and the importance of the charge

The present paper describes synthesis and spectroscopic properties of novel cationic meso-tetraphenylporphyrins bearing two (trans) (P2) or three (P3) triphenylphosphonium substituents. The porphyrin aggregation in aqueous solutions is discussed in detail. Porphyrin binding to and self-organization onto long-range assemblies on poly(dA-dT)2 or poly(dG-dC)2 were probed by combination of absorption, fluorescence, circular dichroism (CD), transient and resonance light-scattering (RLS) techniques. The higher hydrophobicity of P2 is manifested by more extensive self-organization. Induced CD and intensive RLS indicate binding to the chiral environment on the nucleic acids exterior and exciton coupling between adjacent porphyrin moieties. The CD spectra of P2 on poly(dG-dC), and poly(dA-dT)2 suggest that the binding geometry is essentially independent of the base sequence. The fluorescence lifetime of about 4 ns was attributed to the long-range assembly. In the case of P3 the distinctly different CD spectra induced by GC or AT base-pair regions reveal that the number of the substituents determines how closely the porphyrin can approach the specific electronic environment on the nucleic acid exterior. The fluorescence lifetime of the P3 assembly is about 2 ns.     

Observation of the decay B(0)-->D(+/-)D(*-/+)

We report the first observation of the decay B(0)-->D(+/-)D(*-/+) with the Belle detector at the KEKB e(+)e(-) Collider operated at the Upsilon(4S) resonance. The sum of branching fractions B(B(0)-->D(+)D(*-))+B(B(0)-->D(-)D(*+)) is measured to be (1.17+/-0.26(+0.22)(-0.25))x10(-3) using the full reconstruction method where both charmed mesons from B0 decays are reconstructed. A consistent value [(1.48+/-0.38(+0.28)(-0.31))x10(-3)] is obtained using a partial reconstruction technique that uses only the slow pion from the D(*-)-->D(-0)pi(-) decay and a fully reconstructed D(+) to reconstruct the B(0).     

Stability of mechanical properties of molecular layer–deposited alucone

We report on the effect of aging on the mechanical properties of molecular layer–deposited (MLD) thin films. We studied the mechanical failure of the films during uniaxial tensile testing and observed a sixfold difference in the crack-onset strain (COS) and related flexibility within the first two days after the samples were exposed to ambient air. The MLD films made using trimethylaluminum and ethylene glycol are notorious for exhibiting structural changes after the fabrication; we show that these changes are detrimental for mechanical robustness of the films. This information aids to plan the handling or the protection of these films to achieve better performance with these materials. The interfacial shear strains and COSs of the shortly air-exposed 300-nm-thick films were observed to be roughly 0.3% and 1.8%, respectively. These values are the highest reported so far for hybrid organic–inorganic MLD thin films and would extrapolate to about 14% COS for 5-nm-thick film, indicating potential applications as interfacial adhesion layer for films on polymer substrates and as a protective coating in battery applications.