Pole Diagrams Research Articles

Two-pole structure of the h1(1415) axial-vector meson: Resolving the mass discrepancy

We investigate isoscalar axial-vector mesons using a coupled-channel formalism. The kernel amplitudes are constructed from meson-exchange diagrams in the t and u channels, which are derived from effective Lagrangians based on hidden local symmetry. We incorporate six channels: πρ, ηω, KK¯*, ηϕ, η′ω, and η′ϕ, and solve the off-shell coupled integral equations. We first discuss the dynamical generation of the h1(1170). The pole diagram for h1(1595) has a certain effect on the generation of h1(1170). We observe two poles at (1387−i6) MeV and (1452−i51) MeV, which exhibit a two-pole structure of the h1(1415) meson. This two-pole structure may resolve the discrepancy in the experimental data on the mass of h1(1415). The results show that the lower pole couples strongly to the KK¯* channel, while the higher pole couples predominantly to the ηϕ channel. This provides insights into the nature of h1 mesons and explains possible discrepancies in the mass of h1(1415). Published by the American Physical Society 2024

Analysis of data for γp → f 1(1285)p photoproduction* *Partially supported by the National Natural Science Foundation of China (12175240, 12147153, 11635009, 12305097, 12305137), the Fundamental Research Funds for the Central Universities, and the China Postdoctoral Science Foundation (2021M693141, 2021M693142)

The photoproduction of the meson off the proton target is investigated within an effective Lagrangian approach. The t-channel ρ- and ω-exchange diagrams, u-channel nucleon-exchange diagram, generalized contact term, and s-channel pole diagrams of the nucleon and a minimal number of nucleon resonances are taken into account in constructing the reaction amplitudes to describe the experimental data. Three different models, that is, the Feynman, Regge, and interpolated Regge models, are employed, where the t-channel reaction amplitudes are constructed in Feynman, Regge, and interpolated Regge types, respectively. The results show that neither the Feynman model with two nucleon resonances nor the interpolated Regge model with one nucleon resonance can satisfactorily reproduce the available data for . Nevertheless, in the Regge model, when any one of the , , , , , , , , and resonances is considered, the data can be well described. The resulting resonance parameters are consistent with those advocated in the Particle Data Group (PDG) review. Further analysis shows that, in the high-energy region, the peaks of differential cross sections at forward angles are dominated by the contributions from t-channel ρ- and ω-exchange diagrams, while in low-energy region, the s-channel pole diagrams of resonances also provide significant contributions to the cross sections.

Electron backscatter diffraction study on bonding and crack formation mechanism of laser cladding NiTi alloy on 316 substrate

NiTi alloy was prepared on 316 substrate by laser cladding with the aiming of clarifying the mechanism of crack formation and interface bonding. The intermediate layer generated in situ at the bonding surface possesses a low stress level. The high hardness brittleness caused by Fe element distributed along the molten pool boundary is the starting point of coating cracking, and the crack is transgranular fracture. The pole diagram shows that from the interface to the top of the coating, the preferred grain orientation varies from {100} to {110}, which benefit from the conversion of the maximum temperature gradient.

Study on the phase structure of the interface zone of Cu–Al composite plate in cast-rolling state and different heat treatment temperatures based on EBSD

The phase structure in the interface zone of Cu–Al composite plate was studied by EBSD after casting and rolling and different heat treatment temperatures. The grain sizes of the matrix and intermetallic compounds in the interface zone were analyzed statistically. The spatial distribution characteristics of the transverse, rolled, normal and various phases were characterized by inverse pole diagram. The results show that with the increase of heat treatment temperature, the phase of the interfacial area of the composite plate is rearranged, the residual stress can be released, and the zero resolution decreases. The interface zone of cast-rolled Cu–Al composite plate is composed of a layer of intermetallic compound, which is Al2Cu; Two layers of intermetallic compounds, both Al, were formed in the interfacial area after heat treatment at 300 °C and 400 °C Al2Cu and Al4Cu9;After heat treatment at 450 °C, the interface region is composed of three layers of intermetallic compounds, which is Al2Cu, AlCu, Al4Cu9;The grain size of copper matrix is obviously larger than that of aluminum matrix. Matrix aluminum, matrix copper, Al2Cu.The average grains of Cu are mostly large Angle grain boundaries, and the orientation difference of adjacent grains in aluminum layer is much smaller than that in copper layer. After heat treatment at 300 °C for 1 h, the recrystallization degree of the interface zone of Cu–Al composite plate is low. After heat treatment at 400 °C for 1 h, the recrystallization in the interfacial zone of Cu–Al composite plate is not complete; After annealing at 450 °C for 1 h, the subgrain boundaries in the aluminum layer grow up, and LAGB is basically converted to HAGB. The distribution characteristics of the characteristic appearance direction in the crystal space of each phase were characterized under the conditions of casting and rolling and different heat treatment temperatures. At the same time, the research results provide theoretical basis and scientific title for optimizing the preparation process and high-end application of Cu–Al composite plate.

Rotational blow molding of thermotropic liquid crystal polymers and resulting orientational structure and mechanical properties

Liquid crystal polymers(LCP)is one of the most promising choices of 5G antenna material in the future, but its rigid rod-like macromolecular chain and the lack of melt elasticity make it difficult to produce film. In this paper, LCP film is successfully prepared based on a blow molding device developed in-house which the mandrel rotates in reverse with the outer die and the effect of annular shear on the orientation structure and mechanical properties of LCP film is investigated. SEM graphics show that obvious self-reinforcing fibers and the fiber cross structure are formed in the LCP film under the synergistic effect of annular shear flow field and axial extrusion. Polarization infrared pole diagram and 2D-WAXD results prove that the orientation degree of LCP film tends to be uniform with the increase of rotational speed. The tensile results show that the die rotation greatly reduces the gap between the longitudinal and transverse mechanical properties of the film, and even the transverse properties exceed the longitudinal properties at the rotational speed of 55 rpm. The LCP film with uniform mechanical properties is obtained eventually. • LCP film was successfully prepared based on a self-made blow molding device which the mandrel rotates in reverse with the outer die. • The rotation of the die made the LCP film formed a fibers cross structure. • The rotation die can effectively promote the orientation of the LCP molecular chain in all directions. • The transverse tensile strength of the RLCP55 exceeds the longitudinal strength.

Analysis of the nonleptonic two-body decays of the Λ hyperon

We systematically study two-body nonleptonic decays of light lambda hyperon $\Lambda \to p \pi^- (n\pi^0)$ with account for both short- and long-distance effects. The short-distance effects are induced by five topologies of external and internal weak $W^\pm$ exchange, while long-distance effects are saturated by an inclusion of the so-called pole diagrams with intermediate $\frac{1}{2}^+$ and $\frac{1}{2}^-$ baryon resonances. The contributions from $\frac12^+$ resonances are calculated straightforwardly by account for nucleon and $\Sigma$ baryons whereas the contributions from $\frac{1}{2}^-$ resonances are calculated by using the well-known soft-pion theorem in the current-algebra approach. It allows one to express the parity-violating $S$-wave amplitude in terms of parity-conserving matrix elements. From our previous analysis of heavy baryons we know that short-distance effects induced by internal topologies are not suppressed in comparison with external $W$-exchange diagram and must be included for description of data. Here, in the case of $\Lambda$ decays we found that the contribution of external and internal $W$-exchange diagrams is sizably suppressed, e.g., by one order of magnitude in comparison with data, which are known with quite good accuracy. Pole diagrams play the major role to get consistency with experiment.

A Drawing System for Pole Diagram and Rose Diagram of Rock Mass Structural Surface

The distribution of structural planes is complex and irregular. How to quickly and effectively obtain the occurrence and distribution characteristics of structural planes and improve the efficiency of data processing is a key technical issue in structural plane analysis. The paper combined fuzzy equivalent clustering algorithm, rose diagram drawing method, and C++ language, developed a drawing system for the pole diagram and rose diagram of rock mass structural planes, and verified the practicability of the system through an engineering case analysis. In the article, the fuzzy equivalent clustering of the occurrence of structural planes, the drawing of pole diagram, and the statistical analysis of structural planes were realized based on the fuzzy equivalent clustering algorithm. The rapid drawing of the striking rose diagram, trending rose diagram, and dip rose diagram module were realized based on the rose diagram drawing method. The system integrated the structure plane pole diagram and the occurrence rose diagram together and realized the rapid analysis and drawing of the structure plane.

Effects of Y content on microstructures and thermal expansion behavior of Mg-Al-Y alloys

Low thermal expansion alloys play an important role in the applications of high-precision instruments because of their excellent dimensional stability under thermal shock. Hence, the effect of Y content on coefficient of thermal expansion (CTE) of Mg-1Al-xY (x = 4, 6, 8, wt. %) alloys were systematically studied. The results showed that the volume fraction of second phase increased and the grain size of the Mg alloys decreased with the increases of Y content, resulting in the CTE of Mg-1Al-xY alloys decreased with the increases of Y content. The grain size of the Mg-1Al-6Y alloy was more suitable and the second phase distributed uniformly, which lead to the lowest CTE after multiple cycles. The experimental value and model predictions of CTE of alloys differ greatly at lower temperature and coincide well at high temperature. The XRD and EBSD results proved the existence of residual stress in the three alloys, which reduced the CTEs of the magnesium alloy. While the rotation of crystal grains reduces the residual stress in multiple thermal cycles, increasing the CTEs and stability of thermal cycling of Mg alloys. The pole diagram of Mg alloys revealed that number of thermal cycling has a great effect on the intensity of the texture.

A tristable locally-active memristor and its complex dynamics

It has been well recognized that local activity is the origin of complex dynamics. Many important commercial applications would benefit from the locally-active memristors. To explore the locally active characteristics of memristors, a new tristable voltage-controlled locally-active memristor model is proposed based on Chua's unfolding theorem, which has three asymptotically equilibrium points and three locally-active regions. Non-volatility and the local activity of the memristor are demonstrated by POP (Power-Off Plot) and DC V - I plot. A small-signal equivalent circuit is established on a locally active operating point of the memristor to describe the characteristic of the memristor at the locally active region. Based on the admittance function Y ( i ω , V ) of the small-signal equivalent circuit, the parasitic capacitor and the oscillation frequency of the are determined. The parasitic oscillation circuit consisting of the memristor, a parasitic resistor and a parasitic capacitor is analyzed in detail by Hopf bifurcation theory and the pole diagram of the composite admittance function Y P ( s, Q ) of the parasitic oscillation circuit. Furthermore, by adding an inductor to the periodic parasitic circuit, we derive a simple chaotic circuit whose basic properties and coexisting dynamics are analyzed in detail. We concluded that the locally-active memristor provides the energy for the circuit to excite and maintain the periodic and chaotic oscillations.

Multi-Point Suspension Design and Stability Analysis of a Scaled Hoop Truss Antenna Structure

This paper proposes a scaled model to investigate the dynamic characteristics and stability of a hoop truss antenna on the ground. First, the statically indeterminate equation for the multi-point suspension is established, along with the voltage of the suspension motor calculated. Then the transfer function of the system is theoretically established. The scaled model is established before and after suspension, and the static deformation and natural frequency of the system are obtained by calculation and measurement. There exist the shaking mode and nodding mode. Also, a vibration experiment is conducted for the system to obtain the vibration response. With this, the transfer function is identified by the system identification method, which appears to be of the second order, and the stability is analyzed through the zero pole diagram. The experiment results show that the first two frequencies are close before and after suspension. Moreover, the stability of the system can be judged by the open-loop transfer function. It is concluded that the vibration experimental data of the scaled model can be used as a reference for the large hoop truss antenna structure.

Fracture Analysis of Rocks for Slope Stability Assessment in SiriKot Area, District Haripur, Khyber Pakhtunkhwa, Pakistan

The landslides are common and hazardous the Northern Gandghar Ranges, Pakistan. The slope failures have affected road sections between Ghazi to Sari area (~65 Km) along the Sirikot road in district Haripur, Pakistan. The objectives consist of failure mechanisms, slope sensitivity and remedial measures in potentially unstable. To analyze slope stability and understand failure mechanisms, Inventory Circle Method (ICM) has been employed at six locations. Most of the landslides have been found in the Precambrian metamorphic Manki Formation, consisting of slate, phyllite and schists. The data acquired through ICM technique have been used to measure the density of fractures and hydraulic properties (porosity and permeability). The fracture analysis revealed two episodes of deformation. Rose and pole diagrams were plotted for stress analysis and fracture orientation to determine the direction of principal stress σ1. Geological Strength Index (GSI) also provided details about the interlocking pattern of the rocks. Topple and rock fall were found in the limestone and quartzite. Moreover, the fractures also provided channels for the water to flow through and penetrate the foliation planes, decreasing the friction and causing a landslide.

Influence of III–V substrates on the texture, structural, and optical properties of CdS thin films deposited by chemical bath deposition

We have studied the influence of texture distribution and crystalline structure of the CdS thin films on their optical properties. CdS samples were grown by chemical epitaxy on III–V substrates. Ga-V materials (c-GaAs and h-GaN) were selected due to the newly renovated interest in CdS/III–V heterostructures and their importance in the development of current optical devices, such as light emitter diodes and solar cells. Texture analysis was realized in pole diagrams obtained in a High-Resolution X-ray diffractometer. Measurements were carried out at 2θ = 26.6° and 2θ = 43.9° because these 2θ angles correspond to diffraction signal for cubic and hexagonal CdS phases, respectively. Pole diagrams show fourfold symmetry in the CdS layers deposited on GaAs (100) substrates and sixfold symmetry in CdS layers deposited on GaN (0002) substrates, which indicates that epitaxial CdS films with both crystal structures is possible by a low-cost technique (Chemical Bath Deposition). The structural study was completed with a surface analysis of the CdS samples by atomic force microscopy; the images obtained showed a greater surface roughness in the CdS layers grown on GaN substrates, this result agrees with the texture distribution observed in pole diagrams. Optical properties of radiative and non-radiative recombination were studied by Raman and photoluminescence (PL) spectroscopies. According to PL results, cubic CdS films have better efficiency in the recombination of radiative bands. In addition, we determined that the CdS–A1LO phonon for the cubic monocrystalline phase is located at 302.35 cm−1, which is 0.84 cm−1 smaller than hexagonal structure.

Numerical Modeling of Stress Disturbance Characteristics during Tunnel Excavation

The stress state and principal stress axis changes of the stress‐field tensor are analyzed during the advancement of a tunnel face on the basis of a given case study of the Jinping II Hydropower Station in China. First, the prevailing pole diagram in geology is used to illustrate the rotation of the stress axes as the tunnel face advances. The results show that the orientation adjustments of principal stresses in different positions near the tunnel boundary share common characteristics. The major and minor principal stress axes ahead of the tunnel face will rotate to intersect with the excavation surface at an angle, with the intermediate principal stress axis being almost parallel to the excavation surface. Furthermore, the stress triaxiality that is commonly used to indicate the deformation and damage of metal materials is introduced to describe the stress state change of the excavation‐induced stress. The stress triaxiality is found to represent the stress state change due to the variation in both the magnitude and orientation of the stress‐field tensor. According to the physical meaning and the change law of the stress triaxiality, stress disturbance during tunnel excavation can be divided into four stages, and the stress disturbance zone is divided into a strong disturbance zone and a weak disturbance zone. The disturbance characteristics of different stages and the distribution patterns of various zones are analyzed, which may be useful for practical application in the design and construction of rock tunnels.

Magnetic moments of the spin−1/2 singly charmed baryons in covariant baryon chiral perturbation theory

Recent experimental advances have reignited theoretical interests in heavy-flavor hadrons. In this work, we study the magnetic moments of the spin-1/2 singly charmed baryons up to the next-to-leading order in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. The pertinent low energy constants $g_{1-4}$ are fixed with the help of the quark model and the heavy quark spin flavor symmetry, while the remaining $d_2$, $d_3$, $d_5$ and $d_6$ are determined by fitting to the lattice QCD pion-mass dependent data. We study the magnetic moments as a function of $m_\pi^2$ and compare our results with those obtained in the heavy baryon chiral perturbation theory. We find that the loop corrections induced by the anti-triplet states are dominated by the baryon pole diagram. In addition, we predict the magnetic moments of the spin-1/2 singly charmed baryons and compare them with those of other approaches.

An enhanced bracket polynomial for knotoids

A multi-variable polynomial invariant for knotoids and linkoids, which is an enhancement of the bracket polynomial for knotoids introduced by Turaev, is given by using the concept of a pole diagram which originates in constructing a virtual link invariant. Several features of the polynomial are revealed.

Deuteron Breakup Induced by 778-MeV Protons

An experiment devoted to studying deuteron breakup induced by 778 MeV protons was performed with the aid of a deuterium bubble chamber. Experimental spectra are compared with results of calculations based on multiple-scattering theory that takes into account pole diagrams, elastic rescattering, and final-state interaction. The calculations in question describe a global behavior of the spectra, even though the theory itself was put forth for energies in the region around a few hundred GeV/c.

Texture analysis and epitaxial relationships in Bi2Te3 thin film grown by physical vapor transport on silicon substrates

Controlling the film/substrate crystallographic relationships is of great interest since a good interface results in an improved crystal homogeneity and quality. In this work, texture analysis on Bi2Te3 films grown by physical vapor transport was carried out in order to study the influence of growth conditions such as time and substrate orientation. Two types of substrates were used: Si (1 0 0) and Si (1 1 1). It was found that the c-axis of the hexagonal structure of Bi2Te3 is always perpendicular to the substrate surface, while the orientation of the a-axes depends on the growth parameters. The in-plane orientation of the Bi2Te3 crystallites was improved as the growth time increased and textured epitaxial growth was achieved. The epitaxial relationships between the cubic Si and the hexagonal Bi2Te3 lattices were studied through pole diagrams. It was found that the a-axes of the Bi2Te3 lattice are oriented along the 〈1 1 0〉 directions of the Si surface in both types of substrates. In contrast to other reports, the observed growth rate was not constant, but it decreased with time. This effect is discussed in relation with the characteristic spiral growth mechanism.

Octet baryons in large magnetic fields

Magnetic properties of octet baryons are investigated within the framework of chiral perturbation theory. Utilizing a power counting for large magnetic fields, the Landau levels of charged mesons are treated exactly giving rise to baryon energies that depend non-analytically on the strength of the magnetic field. In the small-field limit, baryon magnetic moments and polarizabilities emerge from the calculated energies. We argue that the magnetic polarizabilities of hyperons provide a testing ground for potentially large contributions from decuplet pole diagrams. In external magnetic fields, such contributions manifest themselves through decuplet-octet mixing, for which possible results are compared in a few scenarios. These scenarios can be tested with lattice QCD calculations of the octet baryon energies in magnetic fields.

Self-consistent account for phonon induced corrections to quadrupole moments of odd nuclei. Pole and non-pole diagrams.

Recent results of the description of quadrupole moments of odd semi-magic nuclei are briefly reviewed. They are based on the self-consistent theory of finite Fermi systems with account for the phonon-particle coupling (PC) effects. The self-consistent model for describing the PC effects was developed previously for magnetic moments. Account for the non-pole diagrams is an important ingredient of this model. In addition to previously reported results for the odd In and Sb isotopes, which are the proton-odd neighbors of even tin nuclei, we present new results for odd Bi isotopes, the odd neighbors of even lead isotopes. In general, account for the PC corrections makes the agreement with the experimental data significantly better.

Re-examining the X(4630) resonance in the reaction e+e−→Λc+Λ¯c−

The reaction $e^+e^-\rightarrow \Lambda^+_c\bar\Lambda^-_c$ is investigated at energies close to the threshold with emphasis on the role played by the $X(4630)$ resonance. The interaction in the final $\Lambda^+_c \bar\Lambda^-_c$ system, constructed within chiral effective field theory and supplemented by a pole diagram that represents a bare $X(4630)$ resonance, is taken into account rigorously. The pole parameters of the $X(4630)$ are extracted and found to be compatible with the ones of the $X(4660)$ resonance that have been established in the reaction $e^+e^- \to \pi^+\pi^-\psi(2S)$. The actual result for the $X(4630)$ is $M = (4652.5\pm 3.4)$ MeV and $\Gamma = (62.6\pm 5.6)$ MeV. Predictions for the $\Lambda^+_c$ electromagnetic form factors in the timelike region are presented.