Momentum-dependence of ρ−ω\rho-\omega mixing in the pion vector form factor and its effect on (g−2)μ(g-2)_\mu

The inclusion of the $\rho-\omega$ mixing effect is crucial for a good description of the pion electromagnetic form factor in the $e^+e^- \rightarrow \pi^+\pi^-$ process, which quantifies the two-pion contribution to the anomalous magnetic moment of the muon $a_\mu$. In this paper, we try to analyze the impact of the momentum-dependence of the $\rho-\omega$ mixing within the framework of resonance chiral theory. The momentum-dependence of the $\rho-\omega$ mixing is incorporated due to the calculation of loop contributions at the next-to-leading order in the $1/N_C$ expansion. The work of {[}Y. H. Chen, D. L. Yao, and H. Q. Zheng, Commun. Theor. Phys. 69 (2018) 1{]} is revisited taking into account the contribution due to the kaon mass splitting in the kaon loops and the latest experimental data. We perform two kinds of fits (with momentum-independent or momentum-dependent $\rho-\omega$ mixing amplitude) describing the $e^+e^-\rightarrow \pi^+\pi^-$ and $\tau\rightarrow \nu_{\tau}2\pi$ data in the energy region of 600$\sim$900 MeV and the decay width of $\omega \rightarrow \pi^+\pi^-$, and compare their results. It is found that taking account of the momentum-dependence of $\rho-\omega$ mixing can describe the pion vector form factor data a little better. For the contribution to the anomalous magnetic moment of the muon $a_\mu^{\pi\pi}|_{[0.6,0.9]\text{GeV}}$, the values of the results in the fits considering the momentum-dependent $\rho-\omega$ mixing amplitude are agree well with those in the fits without including the momentum-dependence of the $\rho-\omega$ mixing within errors. In addition, based on the fitted values of the involved parameters, we find that in the decay width of $\omega \rightarrow \pi^+\pi^-$ the contribution from the direct $\omega_I\pi\pi$ coupling is comparable with the contribution due to the $\rho-\omega$ mixing.Comment: 21 pages, 4 figures. arXiv admin note: text overlap with arXiv:1710.1144

Radioactive Decay of Specific Heavy Elements as an Energy Source for Late-Time Kilonovae and Potential JWST Observations

Revealing the temporal evolution of individual heavy elements synthesized in the merger ejecta from binary neutron star mergers not only improves our understanding of the origin of heavy elements beyond iron but also clarifies the energy sources of kilonovae. In this work, we present a comprehensive analysis of the temporal evolution of the energy fraction of each nuclide based on the $r$-process nucleosynthesis simulations. The heavy elements dominating the kilonova emission within $\sim100$~days are identified, including $^{127}$Sb, $^{128}$Sb, $^{129}$Sb, $^{130}$Sb, $^{129}$Te, $^{132}$I, $^{222}$Rn, $^{223}$Ra, $^{224}$Ra, and $^{225}$Ac. It is found that the late-time kilonova light curve ($t\gtrsim20$~days) is highly sensitive to the presence of the heavy element $^{225}$Ac (with a half-life of 10.0~days). Our analysis shows that the James Webb Space Telescope (JWST), with its high sensitivity in the near-infrared band, is a powerful instrument for the identification of these specific heavy elements.Comment: 7 pages, 8 figures, accepted by MNRA

High cycle fatigue and ratcheting interaction of laser powder bed fusion stainless steel 316L:Fracture behaviour and stress-based modelling

Variations in the physical and mechanical properties of parts made by laser power bed fusion (L-PBF) could be affected by the choice of processing or post-processing strategies. This work examined the influence of build orientation and post-processing treatments (annealing or hot isostatic pressing) on the fatigue and fracture behaviours of L-PBF stainless steel 316L in the high cycle fatigue region, i.e. 104 – 106 cycles. Experimental results show that both factors introduce significant changes in the plastic deformation properties, which affect fatigue strength via the mechanism of fatigue-ratcheting interaction. Cyclic plasticity is characterised by hardening, which promotes mean stress insensitivity and improved fatigue resistance. Fatigue activities, involving the initiation of crack at defects and microstructural heterogeneities, are of greater relevance to the longer life region where the global deformation mode is elastic. As the simultaneous actions of ratcheting and fatigue generate complex nonlinear interactions between the alternating stress amplitude and mean stress, the fatigue properties could not be effectively predicted using traditional stress-based models. A modification to the Goodman relation was proposed to account for the added effects of cyclic plasticity and was demonstrated to produce good agreement with experimental results for both cyclic hardening and softening materials.EDB (Economic Devt. Board, S’pore)Accepted versio

How Authoritarian Leadership and Renqing Orientation Improve Tacit Knowledge Sharing

Following an indigenous approach and fairness theory, we develop a theoretical model to investigate when and how authoritarian leadership will improve tacit knowledge sharing (KS). Drawing on survey data from 309 Chinese employees, we examine whether authoritarian leadership will affect procedural fairness (PF) perception and interactional fairness (IF) perception, which in turn, will affect tacit KS; and examine whether leader renqing orientation (LRO) will moderate these mediation processes. Our data demonstrate that authoritarian leadership is negatively related to IF perception, which is positively related to tacit KS. Moreover, authoritarian leadership significantly increases tacit KS intention through PF perception only when LRO is high. Authoritarian leadership significantly decreases tacit KS intention through PF perception and IF perception only when LRO is low. Theoretical and practical implications are discussed

Safety and efficacy of etomidate and propofol anesthesia in elderly patients undergoing gastroscopy: A double-blind randomized clinical study

The aim of the present study is to compare the safety, efficacy and cost effectiveness of anesthetic regimens by compound, using etomidate and propofol in elderly patients undergoing gastroscopy. A total of 200 volunteers (65–79 years of age) scheduled for gastroscopy under anesthesia were randomly divided into the following groups: P, propofol (1.5–2.0 mg/kg); E, etomidate (0.15-0.2 mg/kg); P+E, propofol (0.75–1 mg/kg) followed by etomidate (0.075-0.1 mg/kg); and E+P, etomidate (0.075-0.01 mg/kg) followed by propofol (0.75–1 mg/kg). Vital signs and bispectral index were monitored at different time points. Complications, induction and examination time, anesthesia duration, and recovery and discharge time were recorded. At the end of the procedure, the satisfaction of patients, endoscopists and the anesthetist were evaluated. The recovery (6.1±1.2 h) and discharge times (24.8±2.8 h) in group E were significantly longer compared with groups P, P+E and E+P (P<0.05). The occurrence of injection pain in group P+E was significantly higher compared with the other three groups (P<0.05). In addition, the incidence of myoclonus and post-operative nausea and vomiting were significantly higher in group P+E compared with the other three groups (P<0.05). There was no statistical difference among the four groups with regards to the patients' immediate, post-procedure satisfaction (P>0.05). Furthermore, there was no difference in the satisfaction of anesthesia, as evaluated by the anesthetist and endoscopist, among the four groups (P>0.05). The present study demonstrates that anesthesia for gastroscopy in elderly patients can be safely and effectively accomplished using a drug regimen that combines propofol with etomidate. The combined use of propofol and etomidate has unique characteristics which improve hemodynamic stability, cause minimal respiratory depression and less side effects, provide rapid return to full activity and result in high levels of satisfaction

Single deep ultraviolet light emission from boron nitride nanotube film

Light in deep ultraviolet DUV region has a wide range of applications and the demand for finding DUV light emitting materials at nanoscale is increasingly urgent as they are vital for building miniaturized optic and optoelectronic devices. We discover that boron nitride nanotubes BNNTs with a well-crystallized cylindrical multiwall structure and diameters smaller than 10 nm can have single DUV emission at 225 nm 5.51 eV. The measured BNNTs are grown on substrate in the form of a thin film. This study suggests that BNNTs may work as nanosized DUV light sources for various applications. © 20

Precise determination of the pole position of the exotic Zc(3900)Z_c(3900)

We perform a unified description of the experimental data of the $\pi^+\pi^-$ and $J/\psi\pi^\pm$ invariant mass spectra for $e^+e^- \rightarrow J/\psi \pi^+\pi^-$ and the $D^0 D^{\ast-}$ mass spectrum for $e^+e^- \rightarrow D^0 D^{\ast-} \pi^+$ at $e^+e^-$ center-of-mass energies 4.23 and 4.26 GeV. The analysis takes into account open-charm meson loops that contain triangle singularities, the $J/\psi\pi$-$D\bar D^*$ coupled-channel interaction respecting unitarity, and the strong $\pi\pi$-$K\bar K$ final state interaction using dispersion relations. The analysis leads to a precise determination of the $Z_c(3900)$ pole with the pole mass and width $(3880.5 \pm 2.6)$ MeV and $(25.5 \pm 2.5)$ MeV, respectively, and hints at that the $D\bar D^*$ molecular and non-molecular components are of similar importance in the $Z_c(3900)$ formation.Comment: 15 pages, 4 figure