Analysis of Using FDI in Ningxia Hui Autonomous Region of China

Improving the use of FDI is an important strategy for the further development of Ningxia economic society． This paper analyzes the use of FDI in Ningxia and points out that the use of FDI in Ningxia still has great potential. The paper proposes that Ningxia should improve the investment environment for further improvement of using FDI

Covariant Light-Front Approach for BcB_c transition form factors

In the covariant light-front quark model, we investigate the form factors of $B_c$ decays into $D, D^*, D_s, D_s^*, \eta_c, J/\psi, B, B^*, B_s, B_s^*$ mesons. The form factors in the spacelike region $q^2<0$ are directly evaluated. To extrapolate the form factors to the full kinematic region, we fit the form factors by adopting a three-parameter form from the spacelike region. $b\to u,d,s$ transition form factors at maximally recoiling point ($q^2=0$) are smaller than $b\to c$ and $c\to d,s$ transition form factors, while the $b\to d,s,c$ form factors at zero recoiling point are close to each other. In the fitting procedure, we find the parameters for the form factors $A_2(B_c\to B^*)$ and $A_2(B_c\to B^*_s)$ strongly depend on the decay constants of $B^*$ and $B_s^*$ mesons. Fortunately, the semileptonic and nonleptonic $B_c$ decays are not sensitive to these form factors. With the form factors, we also investigate the branching fractions, polarizations of the semileptonic $B_c\to Ml\nu$ decays. Semileptonic $B_c\to (\eta_c,J/\psi)l\nu$ and $B_c\to (B_s,B_s^*)l\nu$ decays have much larger branching fractions than $B_c\to (D,D^*,B,B^*)l\nu$. In the three kinds of $B_c\to Vl\nu$ decays, contributions from the longitudinal polarized vector is comparable with those from the transversely polarized vector. These predictions will be tested at the ongoing and forthcoming hadron colliders.Comment: 15 pages, 1 figure, uncertainties reanalyzed, several parts reorganized, conclusions unchange

Perturbative corrections to B→DB \to D form factors in QCD

We compute perturbative QCD corrections to $B \to D$ form factors at leading power in $\Lambda/m_b$, at large hadronic recoil, from the light-cone sum rules (LCSR) with $B$-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to-$B$-meson correlation function with an interpolating current for the $D$-meson is demonstrated explicitly at one loop with the power counting scheme $m_c \sim {\cal O} \left (\sqrt{\Lambda \, m_b} \right )$. The jet functions encoding information of the hard-collinear dynamics in the above-mentioned correlation function are complicated by the appearance of an additional hard-collinear scale $m_c$, compared to the counterparts entering the factorization formula of the vacuum-to-$B$-meson correction function for the construction of $B \to \pi$ from factors. Inspecting the next-to-leading-logarithmic sum rules for the form factors of $B \to D \ell \nu$ indicates that perturbative corrections to the hard-collinear functions are more profound than that for the hard functions, with the default theory inputs, in the physical kinematic region. We further compute the subleading power correction induced by the three-particle quark-gluon distribution amplitudes of the $B$-meson at tree level employing the background gluon field approach. The LCSR predictions for the semileptonic $B \to D \ell \nu$ form factors are then extrapolated to the entire kinematic region with the $z$-series parametrization. Phenomenological implications of our determinations for the form factors $f_{BD}^{+, 0}(q^2)$ are explored by investigating the (differential) branching fractions and the $R(D)$ ratio of $B \to D \ell \nu$ and by determining the CKM matrix element $|V_{cb}|$ from the total decay rate of $B \to D \mu \nu_{\mu}$.Comment: 49 pages, 8 figures, version accepted for publication in JHE

QCD calculations of B→π,KB \to \pi, K form factors with higher-twist corrections

We update QCD calculations of $B \to \pi, K$ form factors at large hadronic recoil by including the subleading-power corrections from the higher-twist $B$-meson light-cone distribution amplitudes (LCDAs) up to the twist-six accuracy and the strange-quark mass effects at leading-power in $\Lambda/m_b$ from the twist-two $B$-meson LCDA $\phi_B^{+}(\omega, \mu)$. The higher-twist corrections from both the two-particle and three-particle $B$-meson LCDAs are computed from the light-cone QCD sum rules (LCSR) at tree level. In particular, we construct the local duality model for the twist-five and -six $B$-meson LCDAs, in agreement with the corresponding asymptotic behaviours at small quark and gluon momenta, employing the QCD sum rules in heavy quark effective theory at leading order in $\alpha_s$. The strange quark mass effects in semileptonic $B \to K$ form factors yield the leading-power contribution in the heavy quark expansion, consistent with the power-counting analysis in soft-collinear effective theory, and they are also computed from the LCSR approach due to the appearance of the rapidity singularities. We further explore the phenomenological aspects of the semileptonic $B \to \pi \ell \nu$ decays and the rare exclusive processes $B \to K \nu \nu$, including the determination of the CKM matrix element $|V_{ub}|$, the normalized differential $q^2$ distributions and precision observables defined by the ratios of branching fractions for the above-mentioned two channels in the same intervals of $q^2$.Comment: 36 pages, 9 figure

Final State Interaction In B→KKB\to KK Decays

We study the final state interaction effects in $B\to KK$ decays. We find that the $t$ channel one-particle-exchange diagrams cannot enhance the branching ratios of $\bar{B^0}\to K^0\bar{K^0}$ and $B^-\to K^0K^-$ very sizably. For the pure annihilation process $\bar{B^0}\to K^+K^-$, the obtained branching ratio by final state interaction is at ${\cal{O}}(10^{-8})$

Intrinsically core-shell plasmonic dielectric nanostructures with ultrahigh refractive index

Topological insulators are a new class of quantum material s with metallic (edge) surface states and insulating bulk states. They demonstrate a variety of novel electronic and optical properties, which make them highly promising electronic, spintronic, and optoelectronic materials. We report on a novel conic plasmonic nanostructure that is made of bulk-insulating topological insulators and has an intrinsic core-shell formation. The insulating (dielectric) core of the nanocone displays an ultrahigh refractive index of up to 5.5 in the near-infrared frequency range. On the metallic shell, plasmonic response and strong backward light scattering were observed in the visible frequency range. Through in- tegrating the nanocone arrays into a-Si thin film solar cel ls, up to 15% enhancement of light absorption was predicted in the ultraviolet and visible ranges. With these unique features, the intrinsically core-shell plasmonic nanostructure paves a new way for designing low-loss and high-performance visible to infrared optical devices