Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity of e^(+)e^(-)collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm=3.773 GeV.The integrated luminosities of the datasets taken from December 2021 to June 2022,from November 2022 to June 2023,and from October 2023 to February 2024 were determined to be 4.995±0.019 fb^(-1),8.157±0.031 fb^(-1),and 4.191±0.016 fb^(-1),respectively,by analyzing large angle Bhabha scattering events.The uncertainties are dominated by systematic effects,and the statistical uncertainties are negligible.Our results provide essential input for future analyses and precision measurements.

Amplitude analysis of the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)

Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.

Determination of the number ofψ(3686)events taken at BESⅢ

The number ofψ(3686)events collected by the BESⅢdetector during the 2021 run period is determined to be(2259.3±11.1)×10~6 by counting inclusiveψ(3686)hadronic events.The uncertainty is systematic and the statistical uncertainty is negligible.Meanwhile,the numbers ofψ(3686)events collected during the 2009 and 2012run periods are updated to be(107.7±0.6)×10~6 and(345.4±2.6)×10~6,respectively.Both numbers are consistent with the previous measurements within one standard deviation.The total number ofψ(3686)events in the three data samples is(2712.4±14.3)×10~6.

N-polar InGaN/GaN nanowires: overcoming the efficiency cliff of red-emitting micro-LEDs

A high efficiency, high brightness, and robust micro or sub-microscale red light emitting diode(LED) is an essential, yet missing, component of the emerging virtual reality and future ultrahigh resolution mobile displays.We report, for the first time, to our knowledge, the demonstration of an N-polar In GaN/GaN nanowire submicroscale LED emitting in the red spectrum that can overcome the efficiency cliff of conventional red-emitting micro-LEDs. We show that the emission wavelengths of N-polar In GaN/GaN nanowires can be progressively shifted from yellow to orange and red, which is difficult to achieve for conventional In GaN quantum wells or Ga-polar nanowires. Significantly, the optical emission intensity can be enhanced by more than one order of magnitude by employing an in situ annealing process of the In GaN active region, suggesting significantly reduced defect formation. LEDs with lateral dimensions as small as ~0.75 μm, consisting of approximately five nanowires, were fabricated and characterized, which are the smallest red-emitting LEDs ever reported, to our knowledge. A maximum external quantum efficiency ~1.2% was measured, which is comparable to previously reported conventional quantum well micro-LEDs operating in this wavelength range, while our device sizes are nearly three to five orders of magnitude smaller in surface area.

Osteogenesis and angiogenesis of a bulk metallic glass for biomedical implants

Implantation is an essential issue in orthopedic surgery.Bulk metallic glasses(BMGs),as a kind of novel materials,attract lots of attentions in biological field owing to their comprehensive excellent properties.Here,we show that a Zr_(61)Ti_(2)Cu_(25)Al_(12)(at.%)BMG(Zr-based BMG)displays the best cytocompatibility,pronounced positive effects on cellular migration,and tube formation from in-vitro tests as compared to those of commercial-pure titanium and poly-ether-ether-ketone.The in-vivo micro-CT and histological evaluation demonstrate the Zr-based BMG can significantly promote a bone formation.Immunofluorescence tests and digital reconstructed radiographs manifest a stimulated effect on early blood vessel formation from the Zr-based BMG.Accordingly,the intimate connection and coupling effect between angiogenesis and osteogenesis must be effective during bone regeneration after implanting Zr-based BMG.Dynamic gait analysis in rats after implanting Zr-based BMG demonstrates a tendency to decrease the pain level during recovery,simultaneously,without abnormal ionic accumulation and inflammatory reactions.Considering suitable mechanical properties,we provide a realistic candidate of the Zr61Ti2Cu25Al12 BMG for biomedical applications.

Greedy nonlinear autoregression for multifidelity computer models at different scales

Although the popular multi-fidelity surrogate models,stochastic collocation and nonlinear autoregression have been applied successfully to multiple benchmark problems in different areas of science and engineering,they have certain limitations.We propose a uniform Bayesian framework that connects these two methods allowing us to combine the strengths of both.To this end,we introduce Greedy-NAR,a nonlinear Bayesian autoregressive model that can handle complex between-fidelity correlations and involves a sequential construction that allows for significant improvements in performance given a limited computational budget.The proposed enhanced nonlinear autoregressive method is applied to three benchmark problems that are typical of energy applications,namely molecular dynamics and computational fluid dynamics.The results indicate an increase in both prediction stability and accuracy when compared to those of the standard multi-fidelity autoregression implementations.The results also reveal the advantages over the stochastic collocation approach in terms of accuracy and computational cost.Generally speaking,the proposed enhancement provides a straightforward and easily implemented approach for boosting the accuracy and efficiency of concatenated structure multi-fidelity simulation methods,e.g.,the nonlinear autoregressive model,with a negligible additional computational cost.