Form factors for B meson weak decays in QCD light cone sum rules with a chiral current correlator

We report some applications of QCD light cone sum rules (LCSR) to \(B\) meson weak decays. Special emphasis is on estimates of the form factors for \(B\) decays into a pseudoscalar ( \(P\) )/vector ( \(V\) ) meson, with a certain chiral current correlator. The main new ingredient, as compared with the case of the standard correlators, is that in the operator product expansion calculations, the contributions due to the twist-3 distribution amplitudes of the related light mesons, which are less known and would bring a larger uncertainty to the calculations with the standard correlators, cancel out fully in the \(B\rightarrow P\) case and do out partially in the \(B\rightarrow V\) one. An important observation, which is similar to that in soft collinear effective theory, is made in twist-3 approximation: whereas only one independent form factor is needed for parameterizing the hadronic matrix elements for a \(B\rightarrow P\) transition induced by all the relevant heavy-light quark currents, there exist two independent form factors under the condition of neglecting the terms suppressed by a factor of \(m_V^2\) , for the \(B\rightarrow V\) transition. Therefore, the improved LCSR approach could be of stronger predictive power for the weak form factors. Also, this approach is employed to understand the \(B\rightarrow D\) transitions by introducing a leading twist-2 DA for an energetic \(D\) meson, combined with some of other QCD-based approaches. A detailed QCD next-to-leading order calculation of the \(B\rightarrow \pi \) form factors is presented for an illustrative purpose, and the sum rule results are used to extract the Cabibbo–Kobayashi–Maskawa matrix element \(|V_{ub}|\) from the latest BaBar data.     

Texture evolution of commercial pure Ti during cold rolling and recrystallization annealing

X-ray diffraction (XRD) was employed to analyze the texture evolution of commercial pure (CP) Ti during cold rolling and recrystallization annealing. The texture components were measured by electron backscattered diffraction (EBSD) after recrystallization annealing. The CP Ti tends to form a texture with the basal pole tilted 30°-40° away from the normal direction toward the transverse direction. The texture of the initial hot-rolled plate can be classified into three kinds, i.e., the pyramid texture (1013)[5230] and (2021)[1015], the basal plane texture (0001)[2110], and the stronger prism texture (1120)[0001]. After cold rolling and annealing (700℃, 60 min), the main texture components are the cold-rolled texture (1125)[1123] and the recrystallized texture (1013)[5230]. The texture (2021)[1015] is inherited from the texture of the initial hot-rolled plate with the decrease of orientation density gradually. The volume contents of the cold-rolled texture {2115} <0110> and the recrystallized texture {1013} <1210> are calculated by EBSD. After recrystallization annealing, the specimen is rich in the recrystallized texture and inherits some of texture components from the cold-rolled texture. When the annealing time is prolonged, the anisotropic value decreases.     

Super-Edge-Connectivity of G(k,d,s)(s≥k/2)

A graph G is super-edge-connected,for short super-λ,if every minimum edge-cut consists of edges adjacent to a vertex of minimum degree.Alphabet overlap graph G(k,d,s)is undirected,simple graph with vertex set V={v|v=1()kv…v;vi∈{1,2,…,d},i=1,…,k}.Two vertices u=(u1…uk)and v=(v1…vk)are adjacent if and only if us+i=vi or vs+i=ui(i=1,…,k-s).In particular G(k,d,1)is just an undirected de Bruijn graph.In this paper,we show that the diameter of G(k,d,s)is k s,the girth is 3.Finally,we prove that G(k,d,s)(s≥k/2)is super-λ.     

The semileptonic decays of B/B s meson in the perturbative QCD approach: a short review

In this short review, we present the current status about the theoretical and experimental studies for some important semileptonic decays of \(B/B_s\) mesons. We firstly gave a brief introduction for the experimental measurements for \(B/B_s \rightarrow P (l^+l^-, l^-\bar{\nu }_l, \nu \bar{\nu })\) decays, the BaBar’s \(R(D)\) and \(R(D^*)\) anomaly, the \(P_5^\prime \) deviation for \(B^0 \rightarrow K^{*0} \mu ^+ \mu ^-\) decay. We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule, the heavy quark effective theory, and the perturbative QCD factorization approach. By using the form factors calculated in the perturbative (pQCD) approach, we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of \(B/B_s\) mesons. We also made careful phenomenological analysis for these pQCD predictions and found, in general, the following points: (a) For all the considered \(B/B_s\) semileptonic decays, the next-to-leading order pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods; (b) For \(R(D)\) and \(R(D^*)\) , the pQCD predictions agree very well with the data, the BaBar’s anomaly of \(R(D^{(*)})\) are therefore explained successfully in the standard model by employing the pQCD approach; and (c) We defined several new ratios \(R_D^{l,\tau }\) and \(R_{D_s}^{l,\tau }\) , they may be more sensitive to the QCD dynamics which controls the \(B/B_s \rightarrow (D^{(*)},D_s^{(*)} )\) transitions than the old ratios, we therefore strongly suggest LHCb and the forthcoming Super- \(B\) experiments to measure these new ratios.     

Higgs precision measurements and flavor physics: a supersymmetric example

Rare decays in flavor physics often suffer from Helicity suppress and Loop suppress. Helicity flip is a direct consequence of chiral \(U(3)\) symmetry breaking and electroweak symmetry breaking. The identical feature is also shared by the mass generation of SM fermions. In this review, we use the Minimal Supersymmetric Standard Model (MSSM) as an example to illustrate an explicit connection between bottom Yukawa coupling and rare decay process of \(b\rightarrow s\gamma \) . We take a symmetry approach to study the common symmetry breaking in supersymmetric correction to bottom quark mass generation and \(b\rightarrow s\gamma \) . We show that Large Peccei-Quinn symmetry breaking effect and \(R\) -symmetry breaking effect required by \(b\rightarrow s\gamma \) inevitably lead to significant reduction of bottom Yukawa \({y}_{b}\) . To compromise the reduction in \(b\bar{b}\) , a new decay is also needed to keep the Higgs total width as the SM value.     

Molecular dynamics simulation of nanoscale contact and sliding processes for probes with different tip radius of curvature

Three-dimensional simulations were carried out molecular dynamics （MD） to study the contact and sliding processes between diamond points with different tip radius of curvature and surfaces of single crystal copper. The material deformation, abrasion mechanism, lattice defects, the force of contact process, and the sliding friction process were investigated. The simulation results show that the contact force, dislocations, and stacking fault defects, increase during the contact process with increasing contact depth or tip radius of curvature. The dislocations emit along the [10i-] and [i-01] direction and then a glide band is formed. It was also found that a greater tip radius of cur- vature results in a larger groove and more material defor- mation. The normal force and friction increase with increasing tip radius of curvature, but the coefficient of friction decreases. The stacking faults spread along the sliding direction and increase with increasing tip radius of curvature. In addition, the number of upheaval atoms increases as the radius of tip curvature or sliding distance increases.     

The loop effects on the chargino decays ～χ±1→～χ0 1ff ′in the MSSM

The lighter chargino three body decays ～χ±1→～χ0 1ff ′ via the W^± boson and the charged Higgs boson H^± were studied in the R-parity conserved Minimal Supersymmetric Standard Model （MSSM）. We treat ～χ±1 decays as production and decay of W^± and H^± i.e.,～χ±1→～χ01W^±（H^±） → χ0 1ff ′. Both higgsino- like and wino-like ～χ±1 decays were well investigated. These decays are calculated at 1-loop level and the loop corrections are found to be less than three percent. The signal of the charged Higgs H^± production from ～χ±1 decays is discussed. It will offer important information about the chargino and neutralino sector, as well as the charged Higgs sector in the MSSM.     

Microstructure and texture evolution in commercial-purity Zr 702 during cold rolling and annealing

Microstructure and texture evolution in commercial-purity Zr 702 during cold rolling and annealing was investigated by optical microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that crystallographic slip was the predominant deformation mechanism in the early stage of deformation. Deformation twins started to form when the rolling reduction was larger than 38.9%; both the dislocation density and the number of twins increased with increasing rolling reduction. The initial texture of the Zr 702 plate consisted of the basal fiber component. During cold rolling the strength of the basal fiber first decreased and then increased with increasing rolling reduction. The cold-rolled sheets were fully recrystallized after being annealed at 550°C. The recrystallization temperature and the size of recrystallized grains decreased with increasing rolling reduction. A larger rolling reduction resulted in a higher grain growth rate when the annealing temperature increased from 550°C to 700°C. The recrystallization texture was characterized by a major basal fiber and a minor {0113}<2110> component. The strength of the recrystallization texture increased with increasing rolling reduction.     

Deterministic secure quantum communication and authentication protocol based on three-particle W state and quantum one-time pad

Three-particle W states are used as decoy photons, and the eavesdropping detection rate reaches 63 %. The positions of decoy photons in information sequence are encoded with identity string ID of the legitimate users. Authentication is implemented by using previously shared identity string. State 丨φ^- ） is used as the carrier. One photon of 丨φ^-） is sent to Bob; and Bob obtains a random key by measuring photons with bases dominated by ID. The bases information is secret to others except Alice and Bob. Both the eavesdropping detection based on three-particle W state and the secret ID ensure the security of the protocol. Unitary operations are not used.     

The two-body hadronic decays of B c meson in the perturbative QCD approach: a short review

Along with the running of Large Hadron Collider (LHC) located at CERN in November 2009, a large number of data samples of \(B_c\) meson have been collected and some hadronic \(B_c\) decay modes have been measured by the LHC experiments. In view of the special and important roles of \(B_c\) meson decays playing in the heavy flavor sector, we here give a short review on the status of two body hadronic decays \(B_c \rightarrow M_1 M_2\) at both experimental and theoretical aspects. For the theoretical progresses, specifically, we will show lots of theoretical studies on two body hadronic \(B_c\) decays involving pseudoscalar, vector, scalar, axial-vector, even tensor meson(s) in the final states by employing the perturbative QCD (pQCD) factorization approach. We will present a general analysis about the two-body hadronic decays of the heavy \(B_c\) meson and also provide some expectations for the future developments.     

Evolution of dark energy–dark matter-coupled expanding universe

The present universe is dominated by repulsive dark energy. It is natural that the coupling between the dark energy and the attractive gravity has to be taken into account in studying the evolution of our universe. Here, we induce an evolution equation for dark energy-dark matter- coupled universe. The solutions of the dynamic equation provide a specific picture of cosmic evolution, which is well compatible with current observed evolution histories of both Hubble parameter and equation of state parameter of dark energy. In this picture, the already observed uni- verse has undergone through three epochs the epoch of equilibrium between gravity and dark energy at cosmo- logical redshifts z 〉 1, the phase transition epoch at z between about 0.5 and 1, and the present acceleration epoch starting from z≌ 0.5. The expected matter-domi- nated deceleration epoch has not been seen yet, which requires future deep observations to look back upon more early universe.     

The nonleptonic two body B decays involving a light tensor meson in final states

The nonleptonic two body \(B_{u,d,s,c}\) decays involving a light tensor meson in final states are studied in the perturbative QCD approach based on \(k_{\mathrm{T}}\) factorization. The decay modes with a tensor meson emitted, are prohibited in naive factorization, since the emission diagram with a tensor meson produced from vacuum is vanished. While contributions from the so-called hard scattering emission diagrams and annihilation type diagrams are important and calculable in the perturbative QCD approach. The branching ratios of most decays are in the range of \(10^{-4}\) – \(10^{-8}\) , which are bigger by 1 or 2 orders of magnitude than the predictions given by the naive factorization, but consistent with the predictions from the QCD factorization and the recent experimental measurements. We also give the predictions for the direct \(CP\) asymmetries, some of which are large enough for the future experiments to measure. We also find that, even with a small mixing angle, the mixing between \(f_2\) and \(f_2^{\prime }\) can bring remarkable changes to both branching ratios and the direct \(CP\) asymmetries for some decays involving \(f_2^{(\prime )}\) mesons. For decays with a vector meson and a tensor meson in final states, we predict a large percentage of transverse polarization contributions due to the contributions of the orbital angular momentum of the tensor mesons.     

A quantum algorithm that deletes marked states from an arbitrary database

We present a general quantum deletion algorithm that deletes M marked states from an N-item quantum database with arbitrary initial distribution. The general behavior of this algorithm is analyzed, and analytic result is given. When the number of marked states is no more than 3N/4 , this algorithm requires just a single query, and this achieves exponential speedup over classical algorithm.     

Single boson realizations of the deformed angular momentum algebra of Witten’s types

By generalizing the Holstein-Primakoff realization and the Dyson realization of the Lie algebra SU(2),various realizations of the deformed angular momentum algebra Rc0,c1,c2q,s,a five-parameter deformed SU(2) by combining Witten’s two deformation schemes,are investigated in terms of the single boson and the single inversion boson respectively.For each kind,the unitary realization,the non-unitary realization,and their connection by the corresponding similarity transformation are respectively discussed.     

Retrieval of column-averaged volume mixing ratio of CO2 with ground-based high spectral resolution solar absorption

The total column-averaged volume mixing ratio of atmospheric carbon dioxide （Xco2） has been retrieved with high spectral resolution solar absorption data obtained from ground-based Fourier transform spectrometer （FTS） measurements at Xichong, a coastal site in the district of Shenzhen in southern China. Based on differential optical absorption spectroscopy （DOAS） theory, the Xco2 was retrieved by finding the best match of observed high spectral resolution solar absorption data and monochromatic radia- tion transfer model calculations. The averaged Xco2 in the whole observation period was about 394.9 ppm. The uncertainty of the retrieval was estimated to be 2.0 ppm （0.51%） by comparing retrievals at two bands. The preliminary results show that Xc% retrieved by this method can be used to validate satellite remote sensing of Xco2.     

Liquid-solid interface control of BFe10-1-1 cupronickel alloy tubes during HCCM horizontal continuous casting and its effect on the microstructure and properties

Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube (?50 mm × 5 mm). HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200–1250℃ mold heating temperature, 50–80 mm/min mean drawing speed, and 500–700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure \((\{ hkl\} < 6\bar 21 > , \{ hkl\} < 2\bar 21 > )\) due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%–47.2% and 210–221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.     

Anomalous top-quark coupling effects in rare B and K decays

The Large Hadron Collider at CERN is performing direct searches for top-quark anomalous flavor-changing neutral current (FCNC) processes. However, these processes may be correlated closely with the low-energy rare \(B\) and \(K\) meson decays. In this paper, we review the anomalous top-quark coupling effects in these low-energy flavor transitions, summarize the flavor constraints and discuss their implications for direct detection of top-FCNC processes at the Large Hadron Collider.     

The impact of nanoporous SiN x interlayer growth position on high-quality GaN epitaxial films

The impact of nanoporous SiN x interlayer growth position on high-quality GaN epitaxial film was elucidated from the behavior of dislocations. The best quality GaN film was achieved when a nanoporous SiN x interlayer was grown on a rough layer, with the high-resolution X-ray diffraction rocking curve full width at half maximum for ( 1102 ) reflection decreasing to 223 arcs, and the total dislocation density reduced to less than 1.0×10 8 cm 2 . GaN films were grown on sapphire substrates by metal organic chemical vapor deposition. The quality of these films was investigated with high-resolution X-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. A preference for the formation of half-loops to reduce threading dislocations was observed when an SiN x interlayer was grown on a rough layer. A growth mechanism is proposed to explain this preference.