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Background: Squeeze Film Damper plays an important role in enhancing the dynamic stability of the rotor and damping rotor vibrations and transmitted forces when traversing critical speeds. Depending on how SFD is designed, SFD can reduce the vibration and transmission forces of the rotating system and it can have the opposite effect. In particular, depending on how the single eccentric rotor system with SFD is mathematically accurately modeled and optimize, the stability of the single eccentric rotor system with SFD is further increased. Purpose: The purpose of this study is to improve the stability of the single eccentric rotor system by optimizing the variables affecting the vibration characteristics of the single eccentric rotor system with SFD. Methods: By using Lagrange function, the dynamic model for the single eccentric rotor system with SFD was comprehensively and specifically mentioned, and the motion equation of centroid path of the single rotor system with SFD was formulated. Next, the optimization design of the single eccentric rotor system with SFD was carried out using a genetic algorithm and MATLAB program. Results: After optimizing the design of the single eccentric rotor system with SFD, the amplitude of the single eccentric rotor system with SFD was reduced by 15.2% compared to before the optimization, and the stability of the single eccentric rotor system was further improved. Conclusion: In this paper, we investigated the dynamic modeling method, the motion equation of centroid path and optimization design method of the single eccentric rotor system with SFD. This results will contribute the nonlinear dynamic behaviors of the single eccentric rotor system, and provide a theoretical basis for the analysis of the dynamic modeling, the optimization design, and the nonlinear dynamic characteristic analysis of the dual rotor system.

One of the main causes for failure in the rotor machine is the presence of internal cracks in the shaft rotating at high speed. The occurrence of such cracks has a dangerous and catastrophic effect on the dynamic behavior of rotating structures and can seriously affect rotating machinery. Due to the destructiveness of the cracks in rotor system, cracks were chosen as the subject of study, and the how to formulate the dynamics equation of the rotor system with and without cracks was explained. In that, the finite element analysis method was combined with the Lagrange method to concretely interpret the equation formulation. Then, the natural frequency matrix and mode of the rotor system without crack and with one crack were determined by using the ANSYS program's tetrahedral mesh and iteration strategies of Runge–Kutta. Furthermore, how the change of the crack position and the non-dimensional crack depth influence the natural frequencies of the rotor system were analyzed in detail. And, the influence of eccentricity on the rotor system and the relationship between eccentricity and nonlinearity were obtained. The result showed that when the eccentric distance and the eccentric mass were relatively small, i.e. 0.05 m, 0.001 kg, the effect on the eccentric force is almost linear, but when the eccentric distance and the eccentric mass were relatively large, i.e. 0.1 m, 0.05 kg, the nonlinear effect of eccentric forces must be considered.

In cloud computing, since the program runs in cloud, it can be written in programming language and maintained only in the cloud after compilation. Due to the heterogeneous nature of the edge node platform, many tasks are migrated from the cloud to the edge terminal. It is not easy to realize the programming under the edge computing, and the maintenance cost is also high. At the same time, because the programmable is a high-risk activity, it has high security requirements. In order to solve this problem, this paper designs a programmable and blockchain security scheme based on the edge computing firework model, realizes the programming of the internet of things (IoT) gateway firework node under the edge computing, and appreciates the safe transmission and storage of programmable data through the blockchain system. The experimental results show that this scheme not only facilitates the user's programming, enhances the real-time performance, and saves the data transmission cost, but also ensures the security and reliability of the system.

The map consists of 11 contigs with a total length of 34.5Mb covering 94 percent of the estimated chromosome size. The fluorescence in situ hybridization (FISH) analysis and physical mapping shows that the short arm and the pricentromeric region of the long arm are rich in heterochromatin indicating that the chromosome is very difficult to sequence.

Under the pressure of energy crisis and environmental pollutions, regulations of automotive emission and energy consumption are becoming more and more stringent. Plug-in Hybrid Electric Vehicle (PHEV), which can solve environmental issues and mileage limitations, becomes the most popular development trend at present. Optimization control of power battery energy contributes greatly to improving vehicle fuel economy and dynamic performance, energy optimization control of vehicle low voltage power supply also has significant influence on vehicle fuel consumption and dynamic performance. In this paper, a Low-Voltage Power Supply Energy Management System (LVPSEMS) is proposed to optimize the energy of low voltage power supply of PHEV. Dynamic management voltage output of DC/DC is conducted and realized based on vehicle states, power battery SOC and low voltage battery status with the purpose of achieving fuel economy and dynamic performance of automobile. The tests in vehicle show that the proposed LVPSEMS and control strategy can effectively improve the pure electric mileage of 1.72% and reduce the electric energy consumption by 4%.

Additive manufacturing, also known as 3D printing, is a revolutionary manufacturing technology. This paper compares the differences between additive manufacturing technologies, such as Fused Deposition Modeling, Selective Laser Sintering, Selective Laser Melting, Stereolithography, Layered Object Manufacturing, and traditional manufacturing processes, such as subtractive and equal manufacturing. The paper mainly discusses the differences between laser additive manufacturing and traditional processing technology in processing principles and materials. The development status of metal alloys, polymer composites, ceramics, and concrete are introduced in the paper. The advantages of metal products manufactured by additive manufacturing technology in mechanical properties and microstructure evolution are highlighted. The paper also identifies the reasons limiting the development of additive manufacturing technology and proposes future prospects, providing a theoretical basis for future research on additive manufacturing technology.

A homogeneous Ni (OH)2/graphene nanosheet (GNS) nanocomposite with excellent supercapacitive performance has been synthesized by a facile chemical precipitation. The Ni (OH)2/GNS nanocomposite presented an ideal morphology with the nanosized Ni (OH)2 particles homogeneously growing on the GNS. Its microstructure, morphology were investigated by XRD, SEM and TEM. The electrochemical performance of the Ni (OH)2/GNS nanocomposite was test by cyclic voltammetry, galvanostatic charge−discharge and electrochemical impedance spectroscopy techniques. The homogeneous Ni (OH)2/GNS nanocomposite exhibited a high specific capacitance of 1667 F/g at a current density of 1A/g and maintained a good stability in 5000 cycles, suggesting that it can be a promising candidate for supercapacitor. The high specific capacitance and remarkable rate capability are promising for applications in supercapacitors with both high energy and power densities. The Ni (OH)2/GNS nanocomposite exhibited large specific capacitance, high rate capability and good cycling stability.

The mixing mechanism of axial-vectors Dsl(2460) and Dsl(2536) is studied via intermediate hadron loops, e.g., D*K, to which both states have strong couplings. By constructing the two-state mixing propagator matrix that respects the unitarity constraint and calculating the vertex coupling form factors in a chiral quark model, we can extract the masses, widths, and mixing angles of the physical states. Two poles can be identified in the propagator matrix. One is at radic; s = 2454.5 MeV corresponding to Dsl (2460) and the other at radic; s = (2544.9 - 1.0 MeV corresponding to Dsl(2460) and Dsl(2536), a large mixing angle ? = 47.5° between 3P1 and 1P1, is obtained. It is driven by the real part of the mixing matrix element and corresponds to ? = 12.3° between the j = 1/2 and j = 3/2 state mixing in the heavy quark limit. For Ds1(2536), a mixing angle ? = 39.7°, which corresponds to ? = 4.4° in the heavy quark limit, is found. An additional phase angle ? = -6.9° ∼ 6.9° is needed at the pole mass of Ds1(2536) since the mixing matrix elements are complex numbers. Both the real and imaginary parts are found important for the large mixing angle. We show that the new experimental data from BABAR provide a strong constraint on the mixing angle at the mass of Ds1(2536), from which two values can be extracted, i.e., ?1=32.1° or ?2 = 38.4°. Our study agrees well with the latter one. Detailed analysis of the mass-shift procedure due to the coupled channel effects is also presented. [ABSTRACT FROM AUTHOR]

There are different families of inequalities that can be used to characterize the entanglement of multiqubit entangled states by the violation of quantum mechanics prediction versus local realism prediction. In a noisy environment, the violation of different inequalities distinguishes a direct from a noise-free environment. That is, each inequality has a different robustness against noise. We investigate theoretically and experimentally this proposition with the Mermin inequality, Bell inequality, and Svetlichny inequality using three-qubit GHZ states for different levels of noise. Our purpose is to determine which one of the inequalities is more robust against noise and thus more suitable to characterize entanglement of states. Our results show that the Mermin inequality is the most robust against stronger noise and is, thus, more suitable for characterizing the entanglement of three-qubit GHZ states in a noisy environment. [ABSTRACT FROM AUTHOR]

With the new measurements of J/ψ and ψ' → γηc(γη'c) from the CLEO and BES-III collaboration, we reinvestigate the intermediate meson loop (IML) contributions to these radiative decays in association with the quark model M1 transitions in an effective Lagrangian approach. It shows that the "unquenched" effects due to the intermediate hadron loops can be better quantified by the new data for J/ψ → γηc. Although the IML contributions are relatively small in J/ψ → γηc, they play a crucial role in ψ' → γηc(γη'c). A prediction for the IML contributions to ψ(3770) → γηc(γη'c) is made. Such unquenched effects allow us to reach a coherent description of those three radiative transitions, and gain some insights into the underlying dynamics. [ABSTRACT FROM AUTHOR]

The global attractivity of the positive steady state is established for a class of nonmonotone time-delayed reaction-diffusion equations subject to the Neumann boundary condition via a fluctuation method. This result is also applied to three population models. [ABSTRACT FROM AUTHOR]

Tissue-engineering bone with porous β-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10–15 ml bone marrow aspirates were harvested from the iliac crest of sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1.073 g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these cell seeded onto porous β-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous β-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in “creep substitution” way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect, of experimental group, only partly in control group. The bone defects in blank group, were non-healing at the 24th week. It was concluded that engineering bones constructed with porous β-TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond “creep substitution” way and making it, healed earlier. Porous β-TCP being constituted with autologous MSC may be a good option in healing critical segmental bone defects in clinical practice and provide insight for future clinical repair of segmental defect.

In order to study the chondrogenic phenotype differentiation of adult sheep bone marrow-derived mesenchymal stem cells (MSCs) in a defined medium as potential seed cells for cartilage tissue engineering, MSCs were isolated by density centrifugation with Percoll solution from bone marrow aspirated from sheep iliac crest. The third passage of MSCs were induced with H-DMEM containing TGF-β3. IGF I. Dexamethasone and VitC. The shape and ultrastructure of cells were observed, toluidine blue stain for GAG and immunohistochemistry for type II collagen were applied for chondrogenic phenotype identification. After 14 days of induction, MSCs changed from a spindle-like appearance to a polynal shape, a large amount of endoplasmic reticulum. Golgi complex and mitochondria were observed, and the differentiation of MSCs chondrogenic phenotype was verified by positive staining of toluidine blue and immunohistochemistry. MSCs derived from bone marrow can differentiate to chondrogenic phenotype when inducedin vitroand can be used as optimal seed cells for cartilage tissue engineering.

Exact periodic-wave solutions to the generalized Nizhnik-Novikov-Veselov (NNV) equation are obtained by using the extended Jacobi elliptic-function method, and in the limit case, the solitary wave solution to NNV equation are also obtained.

In this paper, based on the Lame function and Jacobi elliptic function, the perturbation method is applied to some nonlinear evolution equations to derive their multi-order solutions.

Background: To investigate the dose dependent effect of aprotinin on aggravated pro-inflammatory cytokines in patients with pulmonary hypertension (PH) after cardiopulmonary bypass (CPB). Methods: Thirty-two patients with pulmonary arterial pressure (PAP) above 60 mmHg were recruited. They were assigned randomly to control (Group A, n= 8), and treated groups (Group B with aprotinin = 0.5 × 105KIU/Kg, and Group C with aprotinin = 1.0 × 105KIU/Kg, n= 12 each group). Blood samples were collected at various intervals of time and analyzed, from “0” hour (before CPB as baseline), at the completion of CPB, 4 hours and 24 hours after CPB, to measure the concentrations of interleukin 1β (IL-1β), interleukin-8 (IL-8), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α). Results: All the biomarkers significantly increased after CPB. There was no significant difference in cytokine levels between Group A and group B after CPB. But IL-1β, IL-8 and TNF-α of Group C were not only significantly lower than Group A (p< 0.05), but also lower than Group B at various time points after CPB (p< 0.05). IL-10 of group C was significantly higher than Group A and Group B after CPB (p< 0.05). Conclusions: High dose aprotinin can suppress the release of pro-inflammatory cytokines IL-1β, IL-8 and TNF-α, and enhance the release of IL-10 in patients with PH after CPB. For patients having PH, there exists a simple and potential way to reduce the inflammatory response by applying high dose aprotinin.

The envelope periodic solutions to some nonlinear coupled equations are obtained by means of the Jacobi elliptic function expansion method. And these envelope periodic solutions obtained by this method can degenerate to the envelope shock wave solutions and/or the envelope solitary wave solutions.

We present a systematic study of the productions and decays of light axial vector mesons with JPC=1+± in charmonium decays. In the quark-model scenario, the two axial vector nonets are connected to each other by the Gell-Mann-Okubo mass relation through the mixing between two K¹ states [i.e., K1(1270) and K1(1400)] with configurations of ³P1 and ¹P1. The mixing angles between f1 and f'1 [i.e., f1(1285) and f1(1420)] and between h1 and h'1 [i.e., h1(1170) and h1(1415)] can be reliably constrained. We then introduce the intermediate K*̅K+c.c. meson loop transitions in the description of the productions and decays of these axial vector mesons. The presence of the nearby S-wave K*̅K+c.c., to which these axial vector mesons have strong coupling strengths, turns out to be crucial for understanding many puzzling questions related to their production and decay. This is because the S-wave K*̅K+c.c. rescatterings by the kaon exchange satisfy the triangle singularity (TS) condition in some of these cases and the TS mechanism can introduce special interference effects into the exclusive decays of these light axial vector mesons. [ABSTRACT FROM AUTHOR]

The authors calculate all the geometric parameters corresponding to the representations having integral regular infinitesimal characters of the classical groups, determine all that data to induce those sorts of representations, and get the Langlands classification of the classical groups in those cases.

In this paper we calculate the orbits of flag manifolds of the complex classical groups under the action of the sets of fixed points of Cartan involutions, and determine all the geometric parameters corresponding to representations of the classical groups with integral infinitesimal characters, which are used to discuss Arthur conjecture and the Langlands classification of the irreducible admissible representations of real classical groups(see[1])

Objective: To observe the therapeutic effect of acupuncture therapy for treatment of chronic atrophic gastritis. Methods: According to the theory of TCM, 36 cases of chronic atrophic gastritis were differentiated and treated by acupuncture. Gastroscopy and electrogastrograph (EGG) of the body surface, gastric acid and pepsin, blood gastrin, blood prostaglandin E (PGE), gastric mucosal cells and G cells are recorded. Results: Acupuncture therapy had a better effect in improving clinical symptoms, the markedly effective rate was 97. 2% and the disappearing rate of clinical manifestations 97.02%; after acupuncture treatment, blood PGE concentration increased; gastric acid secretion increased; gastric dynamics was enhanced and the amplitude of EGG rose; acupuncture could significantly facilitate secretion of gastrin. Conclusion: Acupuncture is a convenient treatment method for atrophic gastritis with quick effect and without side effects.

The (2+1)-dimensional Boussinesq equation and (3+1)-dimensional KP equation are studied by using the extended Jacobi elliptic-function method. The exact periodic-wave solutions for the two equations are obtained.

Mg⁺ and Mg⁺+P⁺ were introduced into GaN by ion implantation. The structure and crystalline quality of the GaN samples were analysed by Rutherford backscattering and channelling spectrometry before (χ_min = 1.6%) and after implantation (χ_min = 4.1%). X-ray diffraction reveals the existence of implantation-induced damage in the case of post-implantation followed by rapid thermal annealing. The resistivity, average factor, carrier concentration and carrier mobility were measured by the Hall effect. The transformation from n-type to p-type for GaN was observed.

The multi-order exact solutions of the two-dimensional complex Ginzburg-Landau equation are obtained by making use of the wave-packet theory. In these solutions, the zeroth-order exact solution is a plane wave, the first-order exact solutions are shock waves for the amplitude and spiral waves both between the amplitude and the shift of phase and between the shift of phase and the distance.

In this article, the analyticity of triangle loop integral with complex masses of internal particles is discussed in a new perspective, based on which we obtain the explicit width dependence of the absorptive part of the triangle amplitude. We reanalyze the decay pattern of η (1405/1475) with the width effects included in the triangle singularity (TS) mechanism. Based on the present experimental information, we provide a self-consistent description of the KK¯ π, η π π, and 3 π decay channels for η (1405/1475). Our results confirm the claim that the TS mechanism plays a decisive role in the understanding of the η (1405) and η (1475) puzzle. Namely, the observed differences of η resonances within the mass region of 1.40-1.48 GeV are originated from the same state. For the isospin violated process J/ψ → γ η (1405 / 1475) → f0 (980) π → 3 π, we identify an additional contribution to the a0 (980) - f0 (980) mixing via the TS mechanism. [ABSTRACT FROM AUTHOR]

By studying the very closely lied Ds1D̄s + c.c. and Ds0D̄*s + c.c. thresholds at about 4.43 GeV we investigate the possibilities of a sizeable molecular component inside the ψ(4415) in a unitarization scheme. The ψ(4415) is conventionally assigned as the ψ(4S) state in the quark model. We also consider possible mixings between the ψ(4S) and the quark model state ψ(2D) given their S-wave couplings to both states. A significant coupling for ψ(4415) to the nearby S-wave Ds1D̄s + c.c. and Ds0D̄*s + c.c. thresholds may lead to formation of exotic states Zcs in the decay of ψ(4415) → J/ψKK̄, which is the strange partner of Zc(3900), but has flavor contents of cc̄qs̄ (or cc̄sq̄) with q denoting u/d quarks. Similar to the production of Zc(3900) in e+e- → Y(4260) → J/ψππ via the intermediate D1 (2420)D̄ + c.c. where the so-called "triangle singularity (TS)" kinematics can be recognized, we find that the process e+e- → ψ(4415) → J/ψKK̄via the intermediate Ds1D̄s + c.c. and Ds0D̄*s + c.c. is located at the edge of the TS kinematics. It can provide an ideal case for examining the TS effects and make a difference between a genuine pole structure and kinematic enhancement. [ABSTRACT FROM AUTHOR]

We revisit the mixing mechanism for pseudoscalar mesons and glueball which is introduced by the axial vector anomaly. We demonstrate that the physical mass of the pseudoscalar glueball does not favor to be lower than 1.8 GeV if all the parameters are reasonably constrained. This conclusion, on the one hand, can accommodate the pseudoscalar glueball mass calculated by lattice QCD, and on the other hand, is consistent with the high-statistics analyses at BESIII that all the available measurements do not support the presence of two closely overlapping pseudoscalar states in any exclusive channel. Such a result is in agreement with the recent claim that the slightly shifted peak positions for two possible states η(1405) and η(1475) observed in different channels are actually originated from one single state with the triangle singularity interferences. By resolving this long-standing paradox, one should pay more attention to higher mass region for the purpose of searching for the pseudoscalar glueball candidate. [ABSTRACT FROM AUTHOR]

Antiplatelet agents are widely used in patients with coronary artery disease for the prevention of thrombotic events. However, individual responsiveness to antiplatelet agents is greatly varied, which is deemed as one of the most important risk factors for adverse clinic events, such as thrombosis and bleeding. Although studies on this aspect have lasted for more than a decade, the appropriateness of responsiveness variability monitoring and management for antiplatelet treatment remains controversial. Based on current clinical evidence, expert recommendations by a working group of Chinese Society of Cardiology of Chinese Medical Association were released focused on the methodology, clinical interpretation, and appropriateness of antiplatelet responsiveness variability monitoring and management.

In this work we make a systematic analysis of the correlated processes J/ψ→γŋ(1440)/f1(1420) with ŋ(1440)/f1(1420) → KKπ, ŋππ and 3π, where the role played by the so-called "triangle singularity mechanism" (TSM) is clarified. Our results agree well with the experimental data and suggest a small fraction of f1(1420) contributions in these processes. This study confirms our conclusion [Wu et al. Phys. Rev. Lett. 108, 081803 (2012)] that the dynamic feature of the TSM can be recognized by the strong narrow peak observed in the ππ invariant mass spectrum of ŋ(1440)→ 3π with anomalously large isospin violations. Nevertheless, we explicitly demonstrate that the TSM can produce obvious peak position shifts for the same ŋ(1440) or f1 (1420) state in different decay channels. This is strong evidence that the ŋ(1405) and ŋ(1475) are actually the same state, i.e., ŋ(1440). We also make an analysis of the radiative decays of ŋ(1440) → γV (V = Φ, p0, or ω), which shows that such a one-state prescription seems not to have a conflict with the so-far existing experimental data. Our analysis may shed light on the long-standing puzzling question about the nature of ŋ(1405) and ŋ(1475). [ABSTRACT FROM AUTHOR]

A detailed analysis of the open charm effects on the decays of J/&PSi;(&PSi') → VP is presented, where V stands for light vector meson and P for light pseudoscalar meson. These are the channels that the so-called "12% rule" of perturbative QCD (pQCD) is obviously violated. Nevertheless, they are also the channels that violate the pQCD helicity selection rule at leading order. In this work, we put constraints on the electromagnetic contribution, short-distance contribution from the cc annihilation at the wave function origin, and long-distance contribution from the open charm threshold effects on these two decays. We show that interferences among these amplitudes, in particular, the destructive interferences between the short-distance and long-distance strong amplitudes, play a key role to evade the helicity selection rule and cause the significant deviations from the pQCD expected 12% rule. [ABSTRACT FROM AUTHOR]

We include the &eegr;c meson into the &eegr;-&eegr;'-G mixing formalism constructed in our previous work, where G represents the pseudoscalar gluball. The mixing angles in this tetramixing matrix are constrained by theoretical and experimental implications from relevant hadronic processes. Especially, the angle between &eegr;c and G is found to be about 11° from the measured decay widths of the &eegr;c meson. The pseudoscalar glueball mass mG, the pseudoscalar densities mqq, ss, cc, and the U(l) anomaly matrix elements associated with the mixed states are solved from the anomalous Ward identities. The solution mG &thkap; 1.4 GeV obtained from the &eegr;-&eegr;'-G mixing is confirmed, while mqq grows to above the pion mass, and thus increases perturbative QCD predictions for the branching ratios Br(B → &eegr;'K). We then analyze the &eegr;c-mixing effects on charmonium magnetic dipole transitions, and on the B → &eegr;(1)Ks branching ratios and CP asymmetries, which further improve the consistency between theoretical predictions and data. A predominant observation is that the &eegr;c mixing enhances the perturbative QCD predictions for Br(B → &eegr;'K) by 18%, but does not alter those for Br(B → &eegr;K). The puzzle due to the large Br(B → &eegr;'K) data is then resolved. [ABSTRACT FROM AUTHOR]

We propose to study the open charm effects in e+e- → J/ψη, J/ψπ0 and ϕηc. We show that the exclusive cross section line shapes of these processes would be strongly affected by the open charm effects. Since the final state light meson productions are through soft gluon radiations, we assume a recognition of this soft process via charmed meson loops at the hadronic level. A unique feature among these three reactions is that the DD¯* + c.c. open channel is located in a relatively isolated energy, i.e. ∼3.876 GeV, which is sufficiently far away from the known charmonia ψ(3770) and ψ(4040). Therefore, the cross section line shapes of these reactions may provide an opportunity for singling out the open charm effects with relatively well-defined charmonium contributions. In particular, we find that the reaction e+e- → J/ψπ0 is sensitive to the open charm DD¯ *+c.c. Because of the dominance of the isospin-0 component at the charmonium energy region, we predict an enhanced model-independent cusp effect between the thresholds of D0D¯ *0 + c.c. and D+D*- + c.c. This study can also help us to understand the X(3900) enhancement recently observed by the Belle Collaboration in e+e- → DD¯ + c.c. [ABSTRACT FROM AUTHOR]

We study the Y(4260) production mechanism in e+eâ?' annihilations in the framework of hadronic molecules and investigate the consequence of such a picture in different decay channels. In the hadronic molecule picture the Y(4260) is described as a mixture state composed of a long-ranged DD1(2420)+c.c. molecule state and a compact cc component. We show that the compositeness relation can still provide a reasonable constraint on the wave function renormalization parameter due to the dominance of the molecular component. Such a mechanism can be regarded as a natural consequence of the heavy quark spin symmetry (HQSS) breaking. This study elaborates the molecular picture for the Y(4260) in the e+eâ?' annihilations and affirms that the cross section line shape of e+eâ?'→DD∗π+c.c. in the vicinity of the Y(4260) should have a nontrivial behavior. In this framework we predict that the upper limit of the Y(4260) leptonic decay width is about 500 eV. We also investigate the coupling for D1(2420)→D∗π in the ³P0 quark model and examine the possible HQSS breaking effects due to the deviation from the |¹P1⟩ and |³P1⟩ ideal mixing. This in turn provides a constraint on the HQSS breaking coupling for the Y(4260) to DD1(2420)+c.c. via its cc component. [ABSTRACT FROM AUTHOR]

We demonstrate that the spectacular structures discovered recently in various experiments and named as X, Y and Z states cannot be purely kinematic effects. Their existence necessarily calls for nearby poles in the S matrix and they therefore qualify as states. We propose a way of distinguishing kinematic cusp effects from genuine 5-matrix poles: the kinematic threshold cusp cannot produce a narrow peak in the invariant mass distribution in the elastic channel in contrast with a genuine S-matrix pole. [ABSTRACT FROM AUTHOR]

Since its first observation in 2005, the vector charmonium Y(4260) has turned out to be one of the prime candidates for an exotic state in the charmonium spectrum. It was recently proposed that the Y(4260) should have a prominent D1D + c.c. molecular component that is strongly correlated with the production of the charged Zc(3900). In this paper we demonstrate that the nontrivial cross section line shapes of e+e- → J/ψππ and hcππ can be naturally explained by the molecular scenario. As a consequence we find a significantly smaller mass for the Y(4260) than previously studied. In the e+e- → DD*π + c.c. process, with the inclusion of an additional S-wave D*π contribution constrained from data on the DD* invariant mass distribution, we obtain a good agreement with the data of the angular distributions. We also predict an unusual line shape of Y(4260) in this channel that may serve as a smoking gun for a predominantly molecular nature of Y(4260). Improved measurements of these observables are therefore crucial for a better understanding of the structure of this famous resonance. [ABSTRACT FROM AUTHOR]

In this paper we confront both the hadronic molecule and the hadro-charmonium interpretations of the Y(4260) with the experimental data currently available. We conclude that the data support the Y(4260) being dominantly a D1D+c.c. hadronic molecule while they challenge the hadro-charmonium interpretation. However, additional data are necessary to allow for stronger conclusions. [ABSTRACT FROM AUTHOR]

We provide details of the study of Ψ ( 3770 ) non- D D decays into V P, where V and P denote light vector meson and pseudoscalar meson, respectively. We find that the electromagnetic interaction plays little role in these processes, while the strong interaction dominates. The strong interaction can be separated into two parts, i.e., the short-distance part probing the wave function at origin and the long-distance part reflecting the soft gluon exchanged dynamics. The long-distance part is thus described by the intermediate charmed meson loops. We show that the transition of Ψ ( 3770 ) → V P can be related to Ψ ( 3686 ) → V P such that the parameters in our model can be constrained by comparing the different parts in Ψ ( 3770 ) → V P to those in Ψ ( 3686 ) → V P . Our quantitative results confirm the findings of Zhang et al. ( Phys. Rev. Lett. 102, 172001(2009 )] that the OZI-rule-evading long-distance strong interaction via the intermediate meson loops plays an important role in Ψ ( 3770 ) decays and could be a key towards a full understanding of the mysterious Ψ ( 3770 ) non- D D ; decay mechanism. [ABSTRACT FROM AUTHOR]

The decays of the Zb(10610) and the Zb(10650) to Υ(nS)π, hb(mP)π and χbJ(mP)γ (n=1, 2, 3, m=1, 2 and J=0, 1, 2) are investigated within a nonrelativistic effective field theory. It is argued that, while the decays to Υ(nS)π suffer from potentially large higher order corrections, the P-wave transitions of the Zb states are dominated by a single one-loop diagram and therefore offer the best possibility to confirm the nature of the Zb states as molecular states and to further study their properties. We give nontrivial and parameter-free predictions for the ratios of various partial widths of the Zb and Zb′ into final states with hb(mP)π and χbJ(mP)γ. While such relations appear naturally in the molecular picture for the mentioned transitions, they are not expected to hold for any other scenario. In addition, the branching fractions for the neutral Zb states to χbJγ are predicted to be of order 10-4-10-3. This provides a fine test of the molecular nature in future high-luminosity experiments. [ABSTRACT FROM AUTHOR]

With the recent measurement of Zb(10610) and Zb(10650)→BB "+c.c. and B"B ", we investigate the transitions from the Zb(10610) and Zb(10650) to bottomonium states with emission of a pion via intermediate BB" meson loops. The experimental data can be reproduced in this approach with a commonly accepted range of values for the form factor cutoff parameter α. The Y(3S)π decay channels appear to experience obvious threshold effects which can be understood by the property of the loop integrals. By investigating the α-dependence of partial decay widths and ratios between different decay channels, we show that the intermediate BB" meson loops are crucial for driving the transitions of Zb/Zb'→ Y(nS)π with n = 1, 2, 3, and hb(mP)π with m=1 and 2. [ABSTRACT FROM AUTHOR]

In this work, we present a systematic study of the observed isoscalar tensor f2 states. With the detailed analysis of the mass spectrum and calculation of the f2 two-body strong decays, we extract information from their underlying structures and try to categorize them into the conventional tensor meson family [n³P2 (n = 1, 2, 3, 4) and m³F2 (m = 1, 2)]. We also give predictions for other decay modes of these tensor mesons, which are useful for further experimental investigations. [ABSTRACT FROM AUTHOR]

The strong-isospin violation in &psgr;(3770) → J/&psgr; + &pgr;0 via intermediate D meson loops is investigated in an effective Lagrangian approach. In this process, there is only one D-meson loop contributing to the absorptive part, and the uncertainties due to the introduction of form factors can be minimized. With the help of QCD spectral sum rules (QSSR), we extract the J/&psgr;DD* form factor as an implement from the first principle of QCD. The DD*&pgr;0 form factor can be well determined from the experimental data for D → &pgr;l&ngr;. The exploration of the dispersion relation suggests the dominance of the dispersive part via the intermediate D meson loops even below the open charm threshold. This investigation could provide further insights into the puzzling question on the mechanisms for &psgr;(3770) ¯ non-D&Dmacr; transitions. [ABSTRACT FROM AUTHOR]

Inspired by the newly observed three resonances X(1835), X(2120), and X(2370), in this work we systematically study the two-body strong decays and double pion decays of μ(1295)/μ(1475), μ(1760)/X(1835), and X(2120)/X(2370) by categorizing μ(1295)/μ(1475), μ(1760)/X(1835), X(2120), and X(2370) as the radial excitations of μ(548)/μ'(958). Our numerical results indicate the followings: (1) The obtained theoretical strong decay widths of three pseudoscalar states μ(1295), μ(1475), and μ(1760) are consistent with the experimental measurements; (2) X(1835) could be the second radial excitation of μ'(958); (3) X(2120) and X(2370) can be explained as the third and fourth radial excitations of μ(548)/μ'(958), respectively. The predicted two-body decay patterns of μ(1295)/μ(1475), μ(1760)/X(1835), and X(2120)/X(2370) and their double pion decays should be useful for further testing the conventional meson assignment to μ(1295)/μ(1475), μ(1760)/X(1835), X(2120), and X(2370). [ABSTRACT FROM AUTHOR]

The effects of intermediate charmed mesons on charmonium transitions with the emission of one pion or eta are studied systematically. Based on a nonrelativistic effective field theory we show that charmed meson loops are enhanced compared to the corresponding tree-level contributions for transitions between two S-wave charmonia as well as for transitions between two P-wave charmonia. On the contrary, for the transitions between one S-wave and one P-wave charmonium state, the loops need to be analyzed case by case and often appear to be suppressed. The relation to and possible implications for an effective Lagrangian approach are also discussed. This study at the same time provides a cross-check for the numerical evaluations. [ABSTRACT FROM AUTHOR]