Search for the lepton-flavor-violating decay B 0 → K *0 μ ± e ∓
We have searched for the lepton-flavor-violating decay B0→K∗0μ±e using a data sample of 711 fb-1 that contains 772×106 BB̄ pairs. The data were collected near the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. No signals were observed, and we set 90% confidence level upper limits on the branching fractions of B(B0→K∗0μ+e-)<1.2×10-7, B(B0→K∗0μ-e+)<1.6×10-7, and, for both decays combined, B(B0→K∗0μ±e)<1.8×10-7. These are the most stringent limits on these decays to date. © 2018 authors. Published by the American Physical Society.
With the full data sample of 772×106 BB̄ pairs recorded by the Belle detector at the KEKB electron-positron collider, the decay B̄→D∗τ-ν̄τ is studied with the hadronic τ decays τ-→π-ντ and τ-→ρ-ντ. The τ polarization Pτ(D∗) in two-body hadronic τ decays is measured, as well as the ratio of the branching fractions R(D∗)=B(B̄→D∗τ-ν̄τ)/B(B̄→D∗-ν̄), where - denotes an electron or a muon. Our results, Pτ(D∗)=-0.38±0.51(stat)-0.16+0.21(syst) and R(D∗)=0.270±0.035(stat)-0.025+0.028(syst), are consistent with the theoretical predictions of the standard model. The polarization values of Pτ(D∗)>+0.5 are excluded at the 90% confidence level. © 2018 authors. Published by the American Physical Society.
We report the measurement of γγ→ηc(1S),ηc(2S)→η′π+π- with η′ decays to γρ and ηπ+π- using 941 fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The ηc(1S) mass and width are measured to be M=[2984.6±0.7 (stat)±2.2 (syst)±0.3 (model)] MeV/c2 and Γ=[30.8-2.2+2.3 (stat)±2.5 (syst)±1.4 (model)] MeV, respectively. First observation of ηc(2S)→η′π+π- with a significance of 5.5σ including systematic error is obtained, and the ηc(2S) mass is measured to be M=[3635.1±3.7 (stat)±2.9 (syst)±0.4 (model)] MeV/c2. The products of the two-photon decay width and branching fraction (B) of decays to η′π+π- are determined to be ΓγγΓγγB=[65.4±2.6 (stat)±7.8 (syst)] eV for ηc(1S) and [5.6-1.1+1.2 (stat)±1.1 (syst)] eV for ηc(2S). The cross sections for γγ→η′π+π- and η′f2(1270) are measured for the first time. © 2018 authors. Published by the American Physical Society.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.