ESRF high throughput structural biology workshop

On the Harima Campus, RIKEN is operating two 8 GeV electron accelerators for photon science: SPring-8 and SACLA. They are open for international users through the Japan Synchrotron Radiation Research Institute (JASRI) [1 http://www.spring8.or.jp [Google Scholar]].     

Structure and properties of the one-dimensional cobalt oxide CaCo2O4

We have studied crystal structure and transport properties of the quasi one-dimensional cobalt oxide CaCo₂O₄. The CaCo₂O₄ phase crystallizes in calcium-ferrite type structure, which consists of a corner- and edge-shared CoO₆ octahedron network including one-dimensional double chains. Large thermoelectric power (S  150 μV/K at 390 K) with metallic temperature dependence of S, moderate resistivity (ρ  2.9 × 10⁻¹ Ω cm at 390 K) with carrier localization at low temperature, and normal thermal conductivity (κ  6.3 W/Km at 390 K) were observed. The phonon mean-free path was calculated from the observed data, as a function of temperature. The long phonon mean-free path (l  24 Å at 300 K) implies that the thermal conductivity could be suppressed by impurity scattering of phonons with partial element substitution.     

Epitaxial growth of 4H–SiC{0001} and reduction of deep levels

Homoepitaxial growth of 4H–SiC{0001} by hot-wall chemical vapor deposition (CVD) and characterization of deep levels in both n- and p-type epilayers have been investigated. On 4 off-axis 4H–SiC(0001), formation of macrosteps can be reduced by decreasing the C/Si ratio during CVD, though the growth condition leads to the increase in nitrogen incorporation. The 4H–SiC() face is promising, owing to its very smooth surface morphology even on 4 off-axis substrates and to its superior quality of the oxide/SiC interface. Deep level transient spectroscopy measurements in the wide temperature range from 100 K to 820 K on both n- and p-type 4H–SiC epilayers have revealed almost all the deep levels located in the whole energy range of the bandgap. Thermal annealing at 1350–1700 C of epilayers has resulted in reduction of deep level concentrations by one order of magnitude.     

QCD sum rule study for hidden-strange pentaquarks

Inspired by the LHCb observations of hidden-charm \begin{document}$ P_{c(s)} $\end{document} states, we study their hidden-strange analog\begin{document}$ P_s $\end{document} states in both the \begin{document}$ [udu][\bar ss] $\end{document} and \begin{document}$ [uds][\bar su] $\end{document} configurations. We investigate \begin{document}$ P_s $\end{document} pentaquark states in the \begin{document}$ p\eta^\prime $\end{document}, \begin{document}$ p\phi $\end{document}, \begin{document}$ \Lambda K $\end{document}, \begin{document}$ \Sigma K $\end{document}, and \begin{document}$ \Sigma^\ast K^\ast $\end{document} structures with \begin{document}$J^P ={1}/{2}^-$\end{document} and \begin{document}$ \Sigma ^\ast K $\end{document} and \begin{document}$ \Sigma K^\ast $\end{document} with \begin{document}$J^P = {3}/{2}^-$\end{document} and calculate their masses in the framework of QCD sum rules. Our numerical results show that the extracted hadron masses for all the \begin{document}$ p\eta^\prime $\end{document}, \begin{document}$ p\phi $\end{document}, \begin{document}$ \Lambda K $\end{document}, \begin{document}$ \Sigma K $\end{document}, and \begin{document}$ \Sigma^\ast K^\ast $\end{document} structures are significantly higher than the \begin{document}$ \Sigma K $\end{document} mass threshold, and the masses for \begin{document}$ \Sigma ^\ast K $\end{document} and \begin{document}$ \Sigma K^\ast $\end{document}are also higher than the threshold of the corresponding hadron; hence, no bound state exists in such channels, which is consistent with the current experimental status.     

Constraints on anomalous quartic gauge couplings via Wγjj production at the LHC

Vector boson scattering at the Large Hadron Collider (LHC) is sensitive to anomalous quartic gauge couplings (aQGCs). In this study, we investigate the aQGC contribution to \begin{document}$ W \gamma jj$\end{document} production at the LHC with \begin{document}$\sqrt{s}=13$\end{document} TeV in the context of an effective field theory (EFT). The unitarity bound is applied as a cut on the energy scale of this production process, which is found to have significant suppressive effects on signals. To enhance the statistical significance, we analyze the kinematic and polarization features of the aQGC signals in detail. We find that the polarization effects induced by aQGCs are unique and can discriminate the signals from the SM backgrounds well. With the proposed event selection strategy, we obtain the constraints on the coefficients of dimension-8 operators with current luminosity. The results indicate that the process \begin{document}$pp \to W \gamma jj$\end{document} is powerful for searching for the \begin{document}$O_{M_{2,3,4,5}}$\end{document} and \begin{document}$O_{T_{5,6,7}}$\end{document} operators.     

Null test for cosmic curvature using Gaussian process

The cosmic curvature \begin{document}$ \Omega_{K,0} $\end{document}, which determines the spatial geometry of the universe, is an important parameter in modern cosmology. Any deviation from \begin{document}$ \Omega_{K,0}=0 $\end{document} would have a profound impact on the primordial inflation paradigm and fundamental physics. In this work, we adopt a cosmological model-independent method to test whether \begin{document}$ \Omega_{K,0} $\end{document} deviates from zero. We use the Gaussian process to reconstruct the reduced Hubble parameter \begin{document}$ E(z) $\end{document} and the derivative of the distance \begin{document}$ D'(z) $\end{document} from observational data and then determine \begin{document}$ \Omega_{K,0} $\end{document} with a null test relation. The cosmic chronometer (CC) Hubble data, baryon acoustic oscillation (BAO) Hubble data, and supernovae Pantheon sample are considered. Our result is consistent with a spatially flat universe within the domain of reconstruction \begin{document}$ 0<z<2.3 $\end{document}, at the \begin{document}$ 1\sigma $\end{document} confidence level. In the redshift interval \begin{document}$ 0<z<1 $\end{document}, the result favors a flat universe, while at \begin{document}$ z>1 $\end{document}, it tends to favor a closed universe. In this sense, there is still a possibility for a closed universe. We also carry out the null test of the cosmic curvature at \begin{document}$ 0<z<4.5 $\end{document} using the simulated gravitational wave standard sirens, CC+BAO, and redshift drift Hubble data. The result indicates that in the future, with the synergy of multiple high-quality observations, we can tightly constrain the spatial geometry or exclude the flat universe.     

Tackling the kaon structure function at EicC

Measuring the kaon structure beyond proton and pion structures is a prominent topic in hadron physics, as it is one way to understand the nature of the Nambu-Goldstone boson of QCD and observe the interplay between the EHM and HB mechanisms for hadron mass generation. In this study, we present a simulation of the leading Λ baryon tagged deep inelastic scattering experiment at EicC (Electron-ion collider in China), which is engaged to unveil the internal structure of kaon via the Sullivan process. According to our simulation results, the suggested experiment will cover the kinematical domain of \begin{document}$ 0.05\lesssim x_{\rm K} \lesssim 0.85 $\end{document} and \begin{document}$ Q^2 $\end{document} up to 50 GeV\begin{document}$ ^2 $\end{document}, with the acceptable statistical uncertainties. In the relatively low-\begin{document}$ Q^2 $\end{document} region (\begin{document}$ <10 $\end{document} GeV\begin{document}$ ^2 $\end{document}), the Monte-Carlo simulation shows a good statistical precision (\begin{document}$ <5 $\end{document}%) for the measurement of the kaon structure function \begin{document}$ F_2^{\rm K} $\end{document}. In the high-\begin{document}$ Q^2 $\end{document} region (up to 50 GeV\begin{document}$ ^2 $\end{document}), the statistical uncertainty of \begin{document}$ F_2^{\rm K} $\end{document} is also acceptable (\begin{document}$ <10 $\end{document}%) for the data at \begin{document}$ x_{\rm K}<0.8 $\end{document}. To perform such an experiment at an electron-ion collider, a high-performance zero-degree calorimeter is suggested. The magnitude of the background process and the assumed detector capabilities are also discussed and illustrated in the paper.     

Resonance contributions from χc0 in charmless three-body hadronic B meson decays

Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays \begin{document}$ B_{(s)}\rightarrow h\chi_{c0}\rightarrow h\pi^+\pi^-(K^+K^-) $\end{document} with \begin{document}$ h=\pi, K $\end{document}. We compare our predicted branching ratios for the \begin{document}$ B_{(s)}\rightarrow K\chi_{c0}\rightarrow K\pi^+\pi^-(K^+K^-) $\end{document} decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. However, in the Cabibbo-suppressed decays \begin{document}$ B_{(s)}\rightarrow h\chi_{c0}\rightarrow h\pi^+\pi^-(K^+K^-) $\end{document} with \begin{document}$ h=\bar{K}^0,\pi $\end{document}, the values of the branching ratios are of the order of \begin{document}$ 10^{-7} $\end{document} and \begin{document}$ 10^{-8} $\end{document}. The ratio \begin{document}$ R_{\chi_{c0}} $\end{document} between the decays \begin{document}$B^+\rightarrow $\end{document}\begin{document}$ \pi^+\chi_{c0}\rightarrow \pi^+\pi^+\pi^-$\end{document} and \begin{document}$ B^+\rightarrow K^+\chi_{c0}\rightarrow K^+\pi^+\pi^- $\end{document} and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.     

On the α-q-Mutual Information and the α-q-Capacities

The measures of information transfer which correspond to non-additive entropies have intensively been studied in previous decades. The majority of the work includes the ones belonging to the Sharma–Mittal entropy class, such as the Rényi, the Tsallis, the Landsberg–Vedral and the Gaussian entropies. All of the considerations follow the same approach, mimicking some of the various and mutually equivalent definitions of Shannon information measures, and the information transfer is quantified by an appropriately defined measure of mutual information, while the maximal information transfer is considered as a generalized channel capacity. However, all of the previous approaches fail to satisfy at least one of the ineluctable properties which a measure of (maximal) information transfer should satisfy, leading to counterintuitive conclusions and predicting nonphysical behavior even in the case of very simple communication channels. This paper fills the gap by proposing two parameter measures named the α-q-mutual information and the α-q-capacity. In addition to standard Shannon approaches, special cases of these measures include the α-mutual information and the α-capacity, which are well established in the information theory literature as measures of additive Rényi information transfer, while the cases of the Tsallis, the Landsberg–Vedral and the Gaussian entropies can also be accessed by special choices of the parameters α and q. It is shown that, unlike the previous definition, the α-q-mutual information and the α-q-capacity satisfy the set of properties, which are stated as axioms, by which they reduce to zero in the case of totally destructive channels and to the (maximal) input Sharma–Mittal entropy in the case of perfect transmission, which is consistent with the maximum likelihood detection error. In addition, they are non-negative and less than or equal to the input and the output Sharma–Mittal entropies, in general. Thus, unlike the previous approaches, the proposed (maximal) information transfer measures do not manifest nonphysical behaviors such as sub-capacitance or super-capacitance, which could qualify them as appropriate measures of the Sharma–Mittal information transfer.     

Step formation on hydrogen-etched 6H-SiC{0 0 0 1} surfaces

The formation of step bunches and/or facets on hydrogen-etched 6H-SiC(0 0 0 1) and () surfaces has been studied, using both nominally on-axis and intentionally miscut (i.e. vicinal) substrates. It is found that small miscuts on the (0 0 0 1) surface produce full unit-cell high steps, while half unit-cell high steps are observed on the () surface. The observed step normal direction is found to be for both surfaces. Hence, for intentionally miscut material, a miscut oriented towards this direction produces much better order in the step array compared to a miscut oriented towards a direction. For (0 0 0 1) vicinal surfaces that are miscut towards the direction, the formation of surface ripples is observed for 3° miscut and the development of small facets (nanofacets) is found for higher miscut angles. Much less faceting is observed on miscut () surfaces. Additionally, the (0 0 01) surface is found to have a much larger spatial anisotropy in step energies than the () surface.