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Based on a sample of (10087±44)×106 J/ψ events collected with the BESIII detector, a partial-wave analysis of J/ψ→ΛΣˉ0η+c.c is performed for the first time. The dominant contributions are found to be excited Λ states with JP=1/2− and JP=1/2+ in the ηΛ mass spectra. The measured masses and widths are M=1668.8±3.1±21.2 MeV/c2 and Γ=52.7±4.2±17.8 MeV for the Λ(1670), and M=1881.5±16.5±20.3 MeV/c2 and Γ=82.4±18.2±8.9 MeV for the Λ(1810), respectively. The branching fraction is determined to be B(J/ψ→ΛΣˉ0η+c.c) = (3.44±0.11±0.13)×10−5. The first uncertainties are statistical and the second systematic.
Using data samples with a total integrated luminosity of 22.1 fb−1 at center-of-mass energies between 4.008 and 4.951~GeV collected with the BESIII detector, the cross sections of e+e−→π0π0ψ(3686) process are measured. The obtained cross sections are found to be approximately one-half of those of e+e−→π+π−ψ(3686), consistent with the isospin symmetry expectation. A coherent fit to the dressed cross sections is performed, with the Y(4230)~parameters fixed at the values measured in e+e−→π+π−ψ(3686). The significances of the Y(4390) and Y(4660) are both larger than 5σ, and their masses and widths are consistent with the previous measurement in the e+e−→π+π−ψ(3686) process.
Single-image HDR reconstruction aims to recover high dynamic range radiance from a single low dynamic range (LDR) input, but remains highly ill-posed due to detail saturation in over-exposed regions and noise amplification in under-exposed areas. While recent diffusion-based approaches offer powerful generative priors, they often overlook the exposure-dependent nature of the degradation and incur substantial computational costs from iterative sampling. To address these challenges, we propose ExpoCM, a novel one-step generative HDR reconstruction framework that reformulates HDR reconstruction as a Probability Flow ODE (PF-ODE) and constructs exposure-aware consistency trajectories via exposure-dependent perturbations. Specifically, a soft exposure mask is first constructed to separate the LDR image into over-, under-, and well-exposed regions. Based on this partition, region-conditioned consistency trajectories are designed to hallucinate saturated details, suppress noise in dark regions, and preserve reliable structures within a single, distillation-free inference step. To further enhance perceptual quality, we introduce an Exposure-guided Luminance-Chromaticity Loss in the CIE~L∗a∗b∗ space, which assigns exposure-aware weights to luminance and chromaticity components, effectively mitigating brightness bias and color drift. Extensive experiments on the HDR-REAL, HDR-EYE, and AIM2025 benchmarks demonstrate that ExpoCM achieves state-of-the-art fidelity and perceptual accuracy, while enabling over 400× and 20× faster inference compared to DDPM (1000 steps) and DDIM (50 steps), respectively.
Training tool-calling agents requires large-scale trajectory data with verifiable labels, yet existing approaches either synthesize environments that diverge from real API behavior or generate tasks without ground-truth outcomes for verification. We present FireFly, a pipeline for generating verified tool-call data from real-world MCP servers. Our key insight is to invert the standard synthesis pipeline: rather than generating tasks and hoping they are solvable, we first let a strong LLM explore real APIs along graph-guided DAG structures, then synthesize tasks backward from observed outcomes, guaranteeing label correctness by construction. To handle the scale of real-world tool spaces (∼1,000 tools), we build a pairwise tool graph and sample sub-DAGs to focus exploration on semantically coherent workflows. To address environment drift in live APIs, we construct a retrieval-augmented simulator that caches all exploration results and replays them during training and evaluation, enabling fully offline and reproducible RL. Applying this pipeline yields 5,144 verified tasks spanning 240 servers and 993 tools. A 4B-parameter model trained with GRPO on FireFly matches Claude Sonnet 4.6 on our held-out test set and shows improvements on multiple tool-calling benchmarks including Tau2-Bench, MCPMark, and MCP-Atlas.
We apply a tag-and-probe method to precisely measure the absolute branching fraction of the decay ηc→γγ with the BESIII experiment at BEPCII. Starting with a large initial sample of 2712.4±14.3 million ψ(3686) events, a sample of 0.16 million ηc events are tagged via the golden channel ψ(3686)→π0hc, hc→γηc, effectively avoiding interference effects. The absolute branching fraction of ηc→γγ is measured for the first time to be B(ηc→γγ)=(2.45±0.48stat.±0.09syst.)×10−4. Using the world average value of the total width of the ηc, the partial decay width of ηc→γγ is calculated to be Γ(ηc→γγ)=(7.48±1.48stat.±0.30syst.) keV.
Using 20.3~fb−1 of e+e− annihilation data collected at a center-of-mass energy of 3.773~GeV with the BESIII detector, we report the first observation of the semileptonic decays D0→K−ωe+νe and D+→KS0ωe+νe with significances of 8.0σ and 5.8σ, respectively, including systematic uncertainties. Their decay branching fractions are measured to be B(D0→K−ωe+νe)=(9.3−1.9+2.1±0.7)×10−5 and B(D+→KS0ωe+νe)=(6.6−1.8+2.0±0.6)×10−5. Combining with the latest measurements of D0(+)→K−π+π−(0)e+νe and assuming Kˉ1(1270) to be the sole mediating resonance in all processes, the branching ratios are determined to be Γ(K1(1270)−→K−ω)Γ(K1(1270)−→K−π+π−)=3.4−0.7+0.8±0.3 and Γ(Kˉ1(1270)0→Kˉ0ω)Γ(Kˉ1(1270)0→K−π+π0)=9.6−2.7+3.0±0.8. The combined branching fraction is determined to be B(Kˉ1(1270)→Kˉω)=(7.5±1.3±0.5)%, which is the most precise measurement from a collider experiment. The first uncertainties are statistical, and the second are systematic.
RGB camera-based surveillance systems enable human action recognition for public safety and healthcare, yet raise serious privacy concerns. Existing methods rely on post-capture algorithms, which fail to protect privacy during data acquisition. We propose Lens Privacy Sealing (LPS), a simple hardware solution that physically obscures camera lenses with adjustable laminating film, providing pre-sensor privacy protection at minimal cost. Unlike software methods or expensive engineered optics, LPS achieves strong privacy through stochastic multi-layer scattering that is physically irreversible. We introduce the P3AR dataset for privacy-preserving action recognition, featuring both large-scale replay-captured (P3AR-NTU, 114K videos) and real-world collected (P3AR-PKU) subsets with privacy attribute annotations. To handle video degradation from LPS, we propose MSPNet, a single-stage framework incorporating Inter-Frame Noise Suppressor (IFNS) and Cross-Frame Semantic Aggregator (CFSA), enhanced by contrastive language-image pre-training for robust semantic extraction. Extensive experiments demonstrate that MSPNet with IFNS and CFSA nearly doubles action recognition accuracy compared to baseline methods while suppressing identity recognition to low levels. Comprehensive validation shows LPS achieves a superior privacy-utility trade-off compared to state-of-the-art hardware methods, resists reconstruction attacks including PSF inversion and data-driven recovery, and generalizes robustly across optical configurations and challenging environments. Code is available at https://github.com/wangzy01/MSPNet.
Personalization today is fundamentally platform-centric: services build user representations from the behavioral fragments they observe. Yet no platform can construct a complete picture of the user, as competitive incentives, legal constraints, user privacy concerns, and epistemic limits create persistent data barriers. This paper argues for a shift from platform-centric personalization to user-governed personalization, where only the user can integrate fragmented contexts across platforms and the offline world. The key asymmetry lies in data access: only users can aggregate their own cross-platform and offline information. Large language model (LLM) agents make such integration practically feasible for the first time by enabling reasoning over heterogeneous personal data and transforming users' cross-context information into actionable personalization capabilities. We provide proof-of-concept evidence that users equipped with cross-platform data exports and an off-the-shelf LLM agent can outperform single-platform personalization baselines. We conclude by outlining a research agenda for building scalable user-governed personalization systems.
Based on 4.5 fb−1 of e+e− collision data collected at center-of-mass energies between 4599.53 MeV and 4698.82 MeV with the BESIII detector, the absolute branching fractions of twelve Λc+ hadronic decay modes are measured with a double-tag technique. A global least-square fit is implemented simultaneously among different decay modes at different energy points. This paper gives the most precise results on the branching fractions of different decay modes to date, with precision improved by a factor of 2 to 3. Among them, the branching fraction of Λc+→pK−π+ is determined to be (6.61±0.11±0.12)%, where the first uncertainty is statistical and the second is systematic. In addition, the e+e−→Λc+Λˉc− Born cross sections and the effective form factors (∣Geff∣) at different energy points have been determined with the highest precision to date.
Using a data sample of (2712.4±14.3)×106 ψ(3686) events collected with the BESIII detector operating at the BEPCII collider, we report the first observation of the decays χcJ→2K+2K−ω and χcJ→ϕK+K−ω (J=0,1,2) via the radiative transitions ψ(3686)→γχcJ. The branching fractions of these decays are measured for the first time, and the statistical significance for each signal exceeds 10σ.
The multimodal fusion of images and scene captions has been extensively explored and applied in various fields. However, when dealing with complex remote sensing (RS) scenes, existing studies have predominantly concentrated on architectural optimizations for integrating textual semantic information with visual features, while largely neglecting the generation of high-quality RS captions and the investigation of their effectiveness in multimodal semantic fusion.In this context, we propose the Dynamic MLLM Mixture-of-Experts Perception-Guided Remote Sensing Scene Segmentation, referred to as MPerS.We design multiple prompts for MLLMs to generate high-quality RS captions, enabling MLLMs to perceive RS scenes from diverse expert perspectives. DINOv3 is employed to extract dense visual representations of land-covers.We design a Dynamic MixExperts module that adaptively integrates the most effective textual semantics. Linguistic Query Guided Attention is constructed to utilize textual semantic information to guide visual features for precise segmentation. The MLLMs include LLaVA, ChatGPT, and Qwen. Our method achieves superior performance on three public semantic segmentation RS datasets.
Vision-Language Models (VLMs) are rapidly replacing unimodal encoders in modern retrieval and recommendation systems. While their capabilities are well-documented, their robustness against adversarial manipulation in competitive ranking scenarios remains largely unexplored. In this paper, we uncover a critical vulnerability in VLM-based product search: multimodal ranking attacks. We present Multimodal Generative Engine Optimization (MGEO), a novel adversarial framework that enables a malicious actor to unfairly promote a target product by jointly optimizing imperceptible image perturbations and fluent textual suffixes. Unlike existing attacks that treat modalities in isolation, MGEO employs an alternating gradient-based optimization strategy to exploit the deep cross-modal coupling within the VLM. Extensive experiments on real-world datasets using state-of-the-art models demonstrate that our coordinated attack significantly outperforms text-only and image-only baselines. These findings reveal that multimodal synergy, typically a strength of VLMs, can be weaponized to compromise the integrity of search rankings without triggering conventional content filters.
Using the data sample of 2.7×109 ψ(3686) events collected with the BESIII detector at the BEPCII collider, we present an observation of the Ξ(1530)0 polarization in the decay ψ(3686)→Ξ(1530)0Ξˉ(1530)0 with a significance larger than 20σ compared with all other tested hypotheses. The helicity amplitudes for the process ψ(3686)→Ξ(1530)0Ξˉ(1530)0 and the moduli of form factors including electric charge, magnetic dipole, electric quadrupole, and magnetic octupole are measured for the first time by performing an angular distribution analysis. Additionally, the polarization correlations between Ξ(1530)0 and Ξˉ(1530)0 are measured.
Bikeability assessment is essential for advancing sustainable urban transportation and creating cyclist-friendly cities, and it requires incorporating users' perceptions of safety and comfort. Yet existing perception-based bikeability assessment approaches face key limitations in capturing the complexity of road environments and adequately accounting for heterogeneity in subjective user perceptions. This paper proposes a persona-aware Vision-Language Model framework for bikeability assessment with three novel contributions: (i) theory-grounded persona conditioning based on established cyclist typology that generates persona-specific explanations via chain-of-thought reasoning; (ii) multi-granularity supervised fine-tuning that combines scarce expert-annotated reasoning with abundant user ratings for joint prediction and explainable assessment; and (iii) AI-enabled data augmentation that creates controlled paired data to isolate infrastructure variable impacts. To test and validate this framework, we developed a panoramic image-based crowdsourcing system and collected 12,400 persona-conditioned assessments from 427 cyclists. Experiment results show that the proposed framework offers competitive bikeability rating prediction while uniquely enabling explainable factor attribution.
Data assimilation (DA) has increasingly emerged as a critical tool for state estimation across a wide range of applications. It is significantly challenging when the governing equations of the underlying dynamics are unknown. To this end, various machine learning approaches have been employed to construct a surrogate state transition model in a supervised learning framework, which relies on pre-computed training datasets. However, it is often infeasible to obtain noise-free ground-truth state sequences in practice. To address this challenge, we propose a novel method that integrates reinforcement learning with ensemble-based Bayesian filtering methods, enabling the learning of surrogate state transition model for unknown dynamics directly from noisy observations, without using true state trajectories. Specifically, we treat the process for computing maximum likelihood estimation of surrogate model parameters as a sequential decision-making problem, which can be formulated as a discrete-time Markov decision process (MDP). Under this formulation, learning the surrogate transition model is equivalent to finding an optimal policy of the MDP, which can be effectively addressed using reinforcement learning techniques. Once the model is trained offline, state estimation can be performed in the online stage using filtering methods based on the learned dynamics. The proposed framework accommodates a wide range of observation scenarios, including nonlinear and partially observed measurement models. A few numerical examples demonstrate that the proposed method achieves superior accuracy and robustness in high-dimensional settings.
By analyzing e+e− collision data taken at center-of-mass energies s between 4.600 and 4.699 GeV with the BESIII detector at the BEPCII collider, corresponding to an integrated luminosity of 4.5 fb−1, we study the hadronic decays Λc+→Σ+η and Λc+→Σ+η′ using the single-tag method. The branching fraction ratio of Λc+→Σ+η relative to Λc+→Σ+π0 is determined to be 0.305±0.046stat.±0.007syst., and that of Λc+→Σ+η′ relative to Λc+→Σ+ω is 0.336±0.094stat.±0.037syst.. The ratio of B(Λc+→Σ+η)B(Λc+→Σ+η′) is determined to be 1.73±0.22stat.±0.16syst.. These results enrich our knowledge of charmed baryon decays.
Using (10087±44)×106 J/ψ events collected with the BESIII detector, numerous Ξ− and Λ decay asymmetry parameters are simultaneously determined from the process J/ψ→Ξ−Ξˉ+→Λ(pπ−)π−Λˉ(nˉπ0)π+ and its charge-conjugate channel. The precisions of α0 for Λ→nπ0 and αˉ0 for Λˉ→nˉπ0 compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ→nπ0 to that of Λ→pπ−, ⟨α0⟩/⟨αΛ−⟩, is determined to be 0.873±0.012−0.010+0.011, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5σ, which signifies the existence of the ΔI=3/2 transition in Λ for the first time. Beside, we test for CP violation in Ξ−→Λπ− and in Λ→nπ0 with the best precision to date.
In this paper, we present a new method that reformulates point cloud completion as a set-to-set translation problem and design a new model, called PoinTr, which adopts a Transformer encoder-decoder architecture for point cloud completion. By representing the point cloud as a set of unordered groups of points with position embeddings, we convert the input data to a sequence of point proxies and employ the Transformers for generation. To facilitate Transformers to better leverage the inductive bias about 3D geometric structures of point clouds, we further devise a geometry-aware block that models the local geometric relationships explicitly. The migration of Transformers enables our model to better learn structural knowledge and preserve detailed information for point cloud completion. Taking a step towards more complicated and diverse situations, we further propose AdaPoinTr by developing an adaptive query generation mechanism and designing a novel denoising task during completing a point cloud. Coupling these two techniques enables us to train the model efficiently and effectively: we reduce training time (by 15x or more) and improve completion performance (over 20%). We also show our method can be extended to the scene-level point cloud completion scenario by designing a new geometry-enhanced semantic scene completion framework. Extensive experiments on the existing and newly-proposed datasets demonstrate the effectiveness of our method, which attains 6.53 CD on PCN, 0.81 CD on ShapeNet-55 and 0.392 MMD on real-world KITTI, surpassing other work by a large margin and establishing new state-of-the-arts on various benchmarks. Most notably, AdaPoinTr can achieve such promising performance with higher throughputs and fewer FLOPs compared with the previous best methods in practice. The code and datasets are available at https://github.com/yuxumin/PoinTr
We report a search for a heavier partner of the recently observed Zcs(3985)− state, denoted as Zcs′−, in the process e+e−→K+Ds∗−D∗0+c.c., based on e+e− collision data collected at the center-of-mass energies of s=4.661, 4.682 and 4.699 GeV with the BESIII detector. The Zcs′− is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate K+ recoil-mass spectra, which are probed for a potential contribution from Zcs′−→Ds∗−D∗0 (c.c.). We find an excess of Zcs′−→Ds∗−D∗0 (c.c.) candidates with a significance of 2.1σ, after considering systematic uncertainties, at a mass of (4123.5±0.7stat.±4.7syst.) MeV/c2. As the data set is limited in size, the upper limits are evaluated at the 90\% confidence level on the product of the Born cross sections (σBorn) and the branching fraction (B) of Zcs′−→Ds∗−D∗0, under different assumptions of the Zcs′− mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies. The upper limits of σBorn⋅B are found to be at the level of O(1) pb at each energy. Larger data samples are needed to confirm the Zcs′− state and clarify its nature in the coming years.
With the rapid development of deep learning, training Big Models (BMs) for multiple downstream tasks becomes a popular paradigm. Researchers have achieved various outcomes in the construction of BMs and the BM application in many fields. At present, there is a lack of research work that sorts out the overall progress of BMs and guides the follow-up research. In this paper, we cover not only the BM technologies themselves but also the prerequisites for BM training and applications with BMs, dividing the BM review into four parts: Resource, Models, Key Technologies and Application. We introduce 16 specific BM-related topics in those four parts, they are Data, Knowledge, Computing System, Parallel Training System, Language Model, Vision Model, Multi-modal Model, Theory&Interpretability, Commonsense Reasoning, Reliability&Security, Governance, Evaluation, Machine Translation, Text Generation, Dialogue and Protein Research. In each topic, we summarize clearly the current studies and propose some future research directions. At the end of this paper, we conclude the further development of BMs in a more general view.
Using 6.32 fb−1 of e+e− collision data collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay Ds+→K+π+π− and determine the amplitudes of the various intermediate states. The absolute branching fraction of Ds+→K+π+π− is measured to be (6.11±0.18stat.±0.11syst.)×10−3. The branching fractions of the dominant intermediate processes Ds+→K+ρ0,ρ0→π+π− and Ds+→K∗(892)0π+,K∗(892)0→K+π− are determined to be (1.96±0.19stat.±0.23syst.)×10−3 and (1.85±0.12stat.±0.13syst.)×10−3, respectively. The intermediate resonances f0(500), f0(980), and f0(1370) are observed for the first time in this channel.
Using data collected with the BESIII detector in e+e− collisions at center-of-mass energies between 4.178 and 4.226 GeV and corresponding to 6.32~fb−1 of integrated luminosity, we report the amplitude analysis and branching-fraction measurement of the Ds+→π+π0η′ decay. We find that the dominant intermediate process is Ds+→ρ+η′ and the significances of other resonant and nonresonant processes are all less than 3σ. The upper limits on the branching fractions of S-wave and P-wave nonresonant components are set to 0.10% and 0.74% at the 90% confidence level, respectively. In addition, the branching fraction of the Ds+→π+π0η′ decay is measured to be (6.15±0.25(stat.)±0.18(syst.))%, which receives significant contribution only from Ds+→ρ+η′ according to the amplitude analysis.
Computer-assisted minimally invasive surgery has great potential in benefiting modern operating theatres. The video data streamed from the endoscope provides rich information to support context-awareness for next-generation intelligent surgical systems. To achieve accurate perception and automatic manipulation during the procedure, learning based technique is a promising way, which enables advanced image analysis and scene understanding in recent years. However, learning such models highly relies on large-scale, high-quality, and multi-task labelled data. This is currently a bottleneck for the topic, as available public dataset is still extremely limited in the field of CAI. In this paper, we present and release the first integrated dataset (named AutoLaparo) with multiple image-based perception tasks to facilitate learning-based automation in hysterectomy surgery. Our AutoLaparo dataset is developed based on full-length videos of entire hysterectomy procedures. Specifically, three different yet highly correlated tasks are formulated in the dataset, including surgical workflow recognition, laparoscope motion prediction, and instrument and key anatomy segmentation. In addition, we provide experimental results with state-of-the-art models as reference benchmarks for further model developments and evaluations on this dataset. The dataset is available at https://autolaparo.github.io.
The Born cross sections of the processes e+e−→ωπ0 and e+e−→ωη are measured at center-of-mass energies between 3.773 and 4.701 GeV using a total integrated luminosity of 22.7 fb−1 collected with the BESIII detector operating at the BEPCII collider. A simple s−n dependence for the continuum process can describe the measured Born cross sections. No significant contributions from the ψ(4160), Y(4230), Y(4360), ψ(4415), Y(4660) resonances are found, which indicates relative small branching fractions for these resonances into the ωπ0 and ωη final states.
In this paper, we present a scalable deep learning approach to solve opinion dynamics stochastic optimal control problems with mean field term coupling in the dynamics and cost function. Our approach relies on the probabilistic representation of the solution of the Hamilton-Jacobi-Bellman partial differential equation. Grounded on the nonlinear version of the Feynman-Kac lemma, the solutions of the Hamilton-Jacobi-Bellman partial differential equation are linked to the solution of Forward-Backward Stochastic Differential Equations. These equations can be solved numerically using a novel deep neural network with architecture tailored to the problem in consideration. The resulting algorithm is tested on a polarized opinion consensus experiment. The large-scale (10K) agents experiment validates the scalability and generalizability of our algorithm. The proposed framework opens up the possibility for future applications on extremely large-scale problems.
Using 4.5 fb−1 of e+e− annihilation data samples collected at the center-of-mass energies ranging from 4.600~GeV to 4.699~GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays Λc+→pK−e+νe, Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe is performed. The Λc+→pK−e+νe decay is observed with a significance of 8.2σ and the branching fraction is measured to be B(Λc+→pK−e+νe)=(0.88±0.17stat.±0.07syst.)×10−3. We also report evidence of Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe with significances of 3.3σ and 3.2σ, respectively, and measure B(Λc+→Λ(1520)e+νe)=(1.02±0.52stat.±0.11syst.)×10−3 and B(Λc+→Λ(1405)[→pK−]e+νe)=(0.42±0.19stat.±0.04syst.)×10−3. Combining these with the inclusive semileptonic Λc+ branching fraction measured by BESIII, the relative fraction is determined to be [B(Λc+→pK−e+νe)/B(Λc+→Xe+νe)]=(2.1±0.4stat.±0.2syst.)%, which provides a clear confirmation that semileptonic Λc+ decays are not saturated by the Λℓ+νℓ final state.
In this paper, we present a novel maximum entropy formulation of the Differential Dynamic Programming algorithm and derive two variants using unimodal and multimodal value functions parameterizations. By combining the maximum entropy Bellman equations with a particular approximation of the cost function, we are able to obtain a new formulation of Differential Dynamic Programming which is able to escape from local minima via exploration with a multimodal policy. To demonstrate the efficacy of the proposed algorithm, we provide experimental results using four systems on tasks that are represented by cost functions with multiple local minima and compare them against vanilla Differential Dynamic Programming. Furthermore, we discuss connections with previous work on the linearly solvable stochastic control framework and its extensions in relation to compositionality.
Based on e+e− collision data collected by the BESIII detector at the BEPCII collider at center-of-mass energies from 2.000 to 3.080 GeV, a partial-wave analysis is performed for the process e+e−→K+K−π0. The Born cross section of the process e+e−→K+K−π0 and its subprocesses e+e−→ϕπ0, K∗(892)K and K2∗(1430)K are measured. The results for e+e−→K+K−π0 and ϕπ0 are consistent with the BaBar measurements and with improved precision. By analyzing the cross section, of the subprocesses e+e−→ K∗(892)K and K2∗(1430)K, a structure with mass MR = (2208 ± 19 ± 24) MeV/c2 and width ΓR = (168 ± 24 ± 39) MeV is observed with a combined statistical significance of 7.6σ. The measured resonance parameters suggest it can be identified as the ϕ(2170), thus the results provide valuable input to understand the internal nature of this state.
Using a data sample of ψ(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb−1, we report a measurement of Λ spin polarization in e+e−→ΛΛˉ at s=3.773 GeV. The significance of polarization is found to be 2σ including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the ΛΛˉ helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be ΔΦΨ = ΦEΨ−ΦMΨ = (71−46+66 ± 5)∘. Similarly, the ratio between the form factors is found to be Rψ = ∣GEΨ/GMΨ∣ = 0.48−0.07+0.12 ± 0.04. The first uncertainties are statistical and the second systematic.
The decays D→K−π+π+π− and D→K−π+π0 are studied in a sample of quantum-correlated DDˉ pairs produced through the process e+e−→ψ(3770)→DDˉ, exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb−1. Here D indicates a quantum superposition of a D0 and a Dˉ0 meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle γ of the Unitarity Triangle in B−→DK− decays at the LHCb and Belle II experiments. The coherence factors are determined to be RK3π=0.52−0.10+0.12 and RKππ0=0.78±0.04, with values for the average strong-phase differences that are δDK3π=(167−19+31)∘ and δDKππ0=(196−15+14)∘, where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the D→K−π+π+π− to yield results that will allow for a more sensitive measurement of γ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6∘.
The radiative hyperon decay Λ→nγ is studied using (10087±44)×106 J/ψ events collected with the BESIII detector operating at BEPCII. The absolute branching fraction of the decay Λ→nγ is determined with a significance of 5.6σ to be [0.832±0.038(stat.)±0.054(syst.)]×10−3, which lies significantly below the current PDG value. By analyzing the joint angular distribution of the decay products, the first determination of the decay asymmetry αγ is reported with a value of −0.16±0.10(stat.)±0.05(syst.).
Analyzing (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector at the BEPCII collider, the ψ(3686)→ωKS0KS0 decay is observed for the first time. The branching fraction for this decay is determined to be Bψ(3686)→ωKS0KS0=(7.04±0.39±0.36)×10−5, where the first uncertainty is statistical and the second is systematic.
Using 2.93fb−1 of e+e− collision data collected at a center-of-mass energy of 3.773\,GeV with the BESIII detector, we present a measurement of the branching fraction of the doubly Cabibbo-suppressed (DCS) decay D0→K+π−π0 and a search for the DCS decay D0→K+π−π0π0. The branching fraction of D0→K+π−π0 is determined to be [3.13−0.56+0.60(stat)±0.09(syst)]×10−4. No signal is observed for D0→K+π−π0π0 and an upper limit of 3.6×10−4 is set on the branching fraction at the 90\% C.L. We combine these results with the world-average branching fractions of their counterpart Cabibbo-favored decays to determine the ratios of the doubly Cabibbo-suppressed over the Cabibbo-favored branching fractions, B(D0→K+π−π0)/B(D0→K−π+π0)=(0.22±0.04)%~and B(D0→K+π−π0π0)/B(D0→K−π+π0π0)<0.40% at the 90\% C.L., which correspond to (0.75±0.14)tan4θC~and 1.37×tan4θC, respectively, where θC is the Cabibbo angle.
Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron Positron Collider II storage rings, the value of R≡σ(e+e−→hadrons)/σ(e+e−→μ+μ−) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0%, and are dominated by systematic uncertainties.
Using data samples with an integrated luminosity of 19 fb−1 at twenty-eight center-of-mass energies from 3.872 GeV to 4.700 GeV collected with the BESIII detector at the BEPCII electron--positron collider, the process e+e−→ηπ+π− and the intermediate process e+e−→ηρ0 are studied for the first time. The Born cross sections are measured. No significant resonance structure is observed in the cross section lineshape.
Using e+e− annihilation data sets collected with the BESIII detector, we measure the cross sections of the processes e+e−→e+e− and e+e−→μ+μ− at fifteen center-of-mass energy points in the vicinity of the J/ψ resonance. By a simultaneous fit to the measured, center-of-mass energy dependent cross sections of the two processes, the combined quantities ΓeeΓee/Γtot and ΓeeΓμμ/Γtot are determined to be (0.346±0.009) and (0.335±0.006) keV, respectively, where Γee, Γμμ, and Γtot are the electronic, muonic, and total decay widths of the J/ψ resonance, respectively. Using the resultant ΓeeΓμμ/Γtot and ΓeeΓee/Γtot, the ratio Γee/Γμμ is calculated to be 1.031±0.015, which is consistent with the expectation of lepton universality within about two standard deviations. Assuming lepton universality and using the branching fraction of the J/ψ leptonic decay measured by BESIII in 2013, Γtot and Γll are determined to be (93.0±2.1) and (5.56±0.11) keV, respectively, where Γll is the average leptonic decay width of the J/ψ resonance.
We report the first measurements of the absolute branching fractions of D0→KL0ϕ, D0→KL0η, D0→KL0ω, and D0→KL0η′, obtained by analyzing 2.93fb−1 of e+e− collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. Taking the world averages of the branching fractions of D0→KS0ϕ, D0→KS0η, D0→KS0ω, and D0→KS0η′, the KS0-KL0 asymmetry R(D0) in these decay modes are obtained. The CP asymmetries in these decays are also determined. No significant CP violation is observed.
By analyzing an electron-positron collision data sample corresponding to an integrated luminosity of 2.93fb−1 taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, we obtain for the first time the absolute branching fractions for seven D0 and D+ hadronic decay modes and search for the hadronic decay D0→KS0KS0π0 with much improved sensitivity. The results are B(D0→KS0π0π0π0)=(7.64±0.30±0.29)×10−3, B(D0→K−π+π0π0π0)=(9.54±0.30±0.31)×10−3, B(D0→KS0π+π−π0π0)=(12.66±0.45±0.43)×10−3, B(D+→KS0π+π0π0)=(29.04±0.62±0.87)×10−3, B(D+→KS0π+π+π−π0)=(15.28±0.57±0.60)×10−3, B(D+→KS0π+π0π0π0)=(5.54±0.44±0.32)×10−3, B(D+→K−π+π+π0π0)=(4.95±0.26±0.19)×10−3, B(D0→KS0KS0π0)<1.57×10−4 at the 90\% confidence level. Here the first uncertainties are statistical and the second ones systematic. The newly studied decays greatly enrich the knowledge of the D→Kˉπππ and D→Kˉππππ hadronic decays, and open a bridge to access more two-body hadronic D decays containing scalar, vector, axial and tensor mesons in the charm sector.
Demand estimation plays an important role in dynamic pricing where the optimal price can be obtained via maximizing the revenue based on the demand curve. In online hotel booking platform, the demand or occupancy of rooms varies across room-types and changes over time, and thus it is challenging to get an accurate occupancy estimate. In this paper, we propose a novel hotel demand function that explicitly models the price elasticity of demand for occupancy prediction, and design a price elasticity prediction model to learn the dynamic price elasticity coefficient from a variety of affecting factors. Our model is composed of carefully designed elasticity learning modules to alleviate the endogeneity problem, and trained in a multi-task framework to tackle the data sparseness. We conduct comprehensive experiments on real-world datasets and validate the superiority of our method over the state-of-the-art baselines for both occupancy prediction and dynamic pricing.
Using e+e− annihilation data corresponding to an integrated luminosity of 6.32 fb−1 collected at center-of-mass energies between 4.178 GeV and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay Ds+→KS0K+π0 and determine the relative branching fractions and phases for intermediate processes. We observe the a0(1710)+, the isovector partner of the f0(1710) and f0(1770) mesons, in its decay to KS0K+ for the first time. In addition, we measure the ratio B(Ds+→Kˉ0K∗(892)+)B(Ds+→Kˉ∗(892)0K+) to be 2.35−0.23stat.+0.42±0.10syst.. Finally, we provide a precision measurement of the absolute branching fraction B(Ds+→KS0K+π0)=(1.46±0.06stat.±0.05syst.)%.
The hadronic decay ηc(2S)→3(π+π−) is observed with a statistical significance of 9.3 standard deviations using (448.1±2.9)×106 ψ(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ηc(2S) are (3643.4±2.3(stat.)±4.4(syst.)) MeV/c2 and (19.8±3.9(stat.)±3.1(syst.)) MeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction B[ψ(3686)→γηc(2S)]×B[ηc(2S)→3(π+π−)] is measured to be (9.2±1.0(stat.)±0.9(syst.))×10−6. Using B[ψ(3686)→γηc(2S)]=(7.0−2.5+3.4)×10−4, we obtain B[ηc(2S)→3(π+π−)]=(1.31±0.15(stat.)±0.13(syst.)(−0.47+0.64)(extr))×10−2, where the third uncertainty is from B[ψ(3686)→γηc(2S)]. We also measure the χcJ→3(π+π−) (J=0,1,2) decays via ψ(3686)→γχcJ transitions. The branching fractions are B[χc0→3(π+π−)]=(2.080±0.006(stat.)±0.068(syst.))×10−2, B[χc1→3(π+π−)]=(1.092±0.004(stat.)±0.035(syst.))×10−2, and B[χc2→3(π+π−)]=(1.565±0.005(stat.)±0.048(syst.))×10−2.
Using a data sample corresponding to an integrated luminosity of 11.3 fb−1 collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e+e−→π+π−ψ2(3823) cross section and the branching fraction B[ψ2(3823)→γχc1]. For the first time, resonance structure is observed in the cross section line shape of e+e−→π+π−ψ2(3823) with significances exceeding 5σ. A fit to data with two coherent Breit-Wigner resonances modeling the s-dependent cross section yields M(R1)=4406.9±17.2±4.5 MeV/c2, Γ(R1)=128.1±37.2±2.3 MeV, and M(R2)=4647.9±8.6±0.8 MeV/c2, Γ(R2)=33.1±18.6±4.1 MeV. Though weakly disfavored by the data, a single resonance with M(R)=4417.5±26.2±3.5 MeV/c2, Γ(R)=245±48±13 MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the ψ2(3823) state is measured as (3823.12±0.43±0.13) MeV/c2, which is the most precise measurement to date.
Based on (10087±44)×106 J/ψ events collected with the BESIII detector at BEPCII, the double Dalitz decay η′→e+e−e+e− is observed for the first time via the J/ψ→γη′ decay process. The significance is found to be 5.7σ with systematic uncertainties taken into consideration. Its branching fraction is determined to be B(η′→e+e−e+e−)=(4.5±1.0(stat.)±0.5(sys.))×10−6.
Based on 3.19 fb−1 of e+e− collision data accumulated at the center-of-mass energy 4.178 GeV with the BESIII detector operating at the BEPCII collider, the electromagnetic Dalitz decay D∗0→D0e+e− is observed for the first time with a statistical significance of 13.2σ. The ratio of the branching fraction of D∗0→D0e+e− to that of D∗0→D0γ is measured to be (11.08±0.76±0.49)×10−3. By using the world average value of the branching fraction of D∗0→D0γ, the branching fraction of D∗0→D0e+e− is determined to be (3.91±0.27±0.17±0.10)×10−3, where the first uncertainty is statistical, the second systematic and the third external branching fractions.
The singly Cabibbo-suppressed decay Λc+→nπ+ is observed for the first time with a statistical significance of 7.3σ by using 3.9 fb−1 of e+e− collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λc+→nπ+ is measured to be (6.6±1.2stat±0.4syst)×10−4. By taking the upper limit of branching fractions of Λc+→pπ0 from the Belle experiment, the ratio of branching fractions between Λc+→nπ+ and Λc+→pπ0 is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with the current predictions of available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λc+→Λπ+ and Λc+→Σ0π+ are measured to be (1.31±0.08stat±0.05syst)×10−2 and (1.22±0.08stat±0.07syst)×10−2, respectively, which are consistent with previous results.
In this paper, we apply the stochastic search dynamic optimization framework for steering opinion dynamics in a partially active population. The framework is grounded on stochastic optimization theory and relies on sampling of candidate solutions from distributions of the exponential family. We derive the distribution parameter update for an open loop, a feedback, and a novel adaptive feedback policy. All three policies are tested on two different opinion dynamics steering scenarios in simulation and compared against a hand designed feedback policy. The results showcase the effectiveness the framework for opinion dynamics control and the robustness of the adaptive feedback policy with respect to the active agent set size.
Using a sample of (10.09 ± 0.04)×109 J/ψ events collected with the BESIII detector, a partial wave analysis of J/ψ→γη′η′ is performed. The masses and widths of the observed resonances and their branching fractions are reported. The main contribution is from J/ψ→γf0(2020) with f0(2020)→η′η′, which is found with a significance of greater than 25σ. The product branching fraction B(J/ψ→γf0(2020))⋅B(f0(2020)→η′η′) is measured to be (2.63±0.06(stat.)−0.46+0.31(syst.))×10−4.
Using 9.9 fb−1 of e+e− collision data collected by the BESIII detector at center-of-mass energies between 4.15 and 4.30 GeV, we search for the processes e+e−→γX(3872) with X(3872)→π0χc0 and X(3872)→ππχc0. Depending on the fitting model, the statistical significance for X(3872)→π0χc0 ranges from 1.3σ to 2.8σ. We set upper limits (at 90\% C.L.) of B(X(3872)→π+π−J/ψ)B(X(3872)→π0χc0)<3.6, B(X(3872)→π+π−J/ψ)B(X(3872)→π+π−χc0)<0.68, and B(X(3872)→π+π−J/ψ)B(X(3872)→π0π0χc0)<1.7. Combined with the BESIII measurement of X(3872)→π0χc1, we also set an upper limit of B(X(3872)→π0χc1)B(X(3872)→π0χc0)<4.4.
Using an electron-positron collision data sample corresponding to an integrated luminosity of 2.93~fb−1 collected with the BESIII detector at a center-of-mass energy of 3.773 GeV, we search for the baryon and lepton number violating decays D0→pˉe+ and D0→pe−. No obvious signals are found with the current statistics. The upper limits on the branching fractions for D0→pˉe+ and D0→pe− are set to be 1.2×10−6 and 2.2×10−6 at 90\% confidence level, respectively.
Using a data set of electron-positron collisions corresponding to an integrated luminosity of 2.93 fb−1 taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, a search for the baryon (B) and lepton (L) number violating decays D±→n(nˉ)e± is performed. No signal is observed and the upper limits on the branching fractions at the 90% confidence level are set to be 1.43×10−5 for the decays D+(−)→nˉ(n)e+(−) with Δ∣B−L∣=0, and 2.91×10−5 for the decays D+(−)→n(nˉ)e+(−) with Δ∣B−L∣=2 , where Δ∣B−L∣ denotes the change in the difference between baryon and lepton numbers.
A search for invisible decays of the Λ baryon is carried out in the process J/ψ→ΛΛˉ based on (1.0087±0.0044)×1010 J/ψ events collected with the BESIII detector located at the BEPCII storage ring. No signals are found for the invisible decays of Λ baryon, and the upper limit of the branching fraction is determined to be 7.4×10−5 at the 90% confidence level. This is the first search for invisible decays of baryons; such searches will play an important role in constraining dark sector models related to the baryon asymmetry.
A search for the hadronic decays of the hc meson to the final states ppˉπ+π−π0, ppˉη, and ppˉπ0 via the process ψ(3686)→π0hc is performed using (4.48±0.03)×108 ψ(3686) events collected with the BESIII detector. The decay channel hc→ppˉη is observed for the first time with a significance greater than 5σ and a branching fraction of (6.41±1.74±0.53±1.00)×10−4, where the uncertainties are statistical, systematic, and that from the branching fraction of ψ(3686)→π0hc. Strong evidence for the decay hc→ppˉπ+π−π0 is found with a significance of 4.9σ and a branching fraction of (3.84±0.83±0.69±0.58)×10−3. The significances include systematic uncertainties. No clear signal of the decay hc→ppˉπ0 is found, and an upper limit of 6.59×10−4 on its branching fraction is set at the 90% confidence level.
We present the first experimental search for the rare charm decay D0→π0ννˉ. It is based on an e+e− collision sample consisting of 10.6×106 pairs of D0Dˉ0 mesons collected by the BESIII detector at s=3.773 GeV, corresponding to an integrated luminosity of 2.93~fb−1. A data-driven method is used to ensure the reliability of the background modeling. No significant D0→π0ννˉ signal is observed in data and an upper limit of the branching fraction is set to be 2.1×10−4 at the 90% confidence level. This is the first experimental constraint on charmed-hadron decays into dineutrino final states.
A search for the decay hc→π0J/ψ is performed using a sample of hc produced in the reaction e+e−→π+π−hc. The data samples were collected with the BESIII detector at center-of-mass energies between 4.189 and 4.437 GeV, corresponding to a total integrated luminosity of 11 fb−1. No significant signal is observed. Upper limits on the branching ratio B(hc→π0J/ψ)/B(hc→γηc→γK+K−π0) and on the branching fraction B(hc→π0J/ψ) are determined to be 7.5×10−2 and 4.7×10−4 at 90% confidence level, respectively. The latter is derived from the former using the measured branching fraction of the normalization channel. This is the first determination of the upper limit of the decay hc→π0J/ψ.
Conventional point cloud semantic segmentation methods usually employ an encoder-decoder architecture, where mid-level features are locally aggregated to extract geometric information. However, the over-reliance on these class-agnostic local geometric representations may raise confusion between local parts from different categories that are similar in appearance or spatially adjacent. To address this issue, we argue that mid-level features can be further enhanced with semantic information, and propose semantic-affine transformation that transforms features of mid-level points belonging to different categories with class-specific affine parameters. Based on this technique, we propose SemAffiNet for point cloud semantic segmentation, which utilizes the attention mechanism in the Transformer module to implicitly and explicitly capture global structural knowledge within local parts for overall comprehension of each category. We conduct extensive experiments on the ScanNetV2 and NYUv2 datasets, and evaluate semantic-affine transformation on various 3D point cloud and 2D image segmentation baselines, where both qualitative and quantitative results demonstrate the superiority and generalization ability of our proposed approach. Code is available at https://github.com/wangzy22/SemAffiNet.
We present a general framework for optimizing the Conditional Value-at-Risk for dynamical systems using stochastic search. The framework is capable of handling the uncertainty from the initial condition, stochastic dynamics, and uncertain parameters in the model. The algorithm is compared against a risk-sensitive distributional reinforcement learning framework and demonstrates outperformance on a pendulum and cartpole with stochastic dynamics. We also showcase the applicability of the framework to robotics as an adaptive risk-sensitive controller by optimizing with respect to the fully nonlinear belief provided by a particle filter on a pendulum, cartpole, and quadcopter in simulation.
The Born cross sections of the e+e−→D∗+D∗− and e+e−→D∗+D− processes are measured using e+e− collision data collected with the BESIII experiment at center-of-mass energies from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of 15.7 fb−1. The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states.
Using the data samples collected in the energy range from 3.773 to 4.600 GeV with the BESIII detector at the BEPCII collider, we measure the dressed cross sections as a function of center-of-mass energy for e+e−→K+K−π+π−(π0), K+K−K+K−(π0), π+π−π+π−(π0), and ppˉπ+π−(π0). The cross sections for e+e−→K+K−K+K−π0, ppˉπ+π−(π0) are the first measurements. Cross sections for the other five channels are much more precise than previous results in this energy region. We also search for charmonium and charmonium-like resonances, such as the Y(4230), decaying into the same final states. We find evidence of the ψ(4040) decaying to π+π−π+π−π0 with a statistical significance of 3.6σ. Upper limits are provided for other decays since no clear signals are observed.
Using 1310.6×106 J/ψ and 448.1×106 ψ(3686) events collected with the BESIII detector, the branching fractions of J/ψ and ψ(3686) decays to Σ+Σ− are measured to be (10.61±0.04±0.36)×10−4 and (2.52±0.04±0.09)×10−4, respectively. In addition, the ratio of B(ψ(3686)→Σ+Σ−)/B(J/ψ→Σ+Σ−) is determined to be (23.8±1.1)% which violates the "12% rule".
The Born cross-sections and effective form factors for process e+e−→Ξ−Ξˉ+ are measured at eight center-of-mass energies between 2.644 and 3.080 GeV, using a total integrated luminosity of 363.9 pb−1 e+e− collision data collected with the BESIII detector at BEPCII. After performing a fit to the Born cross-section of e+e−→Ξ−Ξˉ+, no significant threshold effect is observed.
The Born cross sections of e+e−→Σ0Σˉ0 are measured at center-of-mass energies from 2.3864 to 3.0200 GeV using data samples with an integrated luminosity of 328.5 pb−1 collected with the BESIII detector operating at the BEPCII collider. The analysis makes use of a novel reconstruction method for energies near production threshold, while a single-tag method is employed at other center-of-mass energies. The measured cross sections are consistent with earlier results from BaBar, with a substantially improved precision. The cross-section lineshape can be well described by a perturbative QCD-driven energy function. In addition, the effective form factors of the Σ0 baryon are determined. The results provide precise experimental input for testing various theoretical predictions.
We study ηc production at center-of-mass energies s from 4.18 to 4.60 GeV in e+e− annihilation data collected with the BESIII detector operating at the BEPCII storage ring, corresponding to 7.3 fb−1 of integrated luminosity. We measure the cross sections of the three different exclusive reactions e+e−→ηcπ+π−π0, e+e−→ηcπ+π−, and e+e−→ηcπ0γ. We find significant ηc production in e+e−→ηcπ+π−π0 at s of 4.23 GeV and 4.26 GeV and observe a significant energy-dependent Born cross section that we measure to be consistent with the production via the intermediate Y(4260) resonance. In addition, we perform a search for a charmonium-like Zc state close to the DDˉ threshold that decays to ηcπ, involving ground state charmonium, and observe no signal. Corresponding upper limits on the cross section of ηc and Zc production are provided, where the yields are not found to be significant.
We present an analysis of the process ψ(3686)→Ω−Ωˉ+ (Ω−→K−Λ, Ωˉ+→K+Λˉ, Λ→pπ−, Λˉ→pˉπ+) based on a data set of 448×106 ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω−Ωˉ+ and the decay parameters of the subsequent decay Ω−→K−Λ (Ωˉ+→K+Λˉ) are measured for the first time by a fit to the angular distribution of the complete decay chain. The branching fraction of ψ(3686)→Ω−Ωˉ+ is measured to be (5.82±0.12±0.24)×10−5, with an improved precision compared to previous measurements.
By analyzing an e+e− annihilation data sample with an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, we determine the absolute branching fractions of the hadronic decays D0→K−π+ω, D0→KS0π0ω, and D+→KS0π+ω to be (3.392±0.044stat±0.085syst)%, (0.848±0.046stat±0.031syst)%, and (0.707±0.041stat±0.029syst)%, respectively. The accuracy of the branching fraction measurement of the decay D0→K−π+ω is improved by a factor of seven compared to the world average value. The D0→KS0π0ω and D+→KS0π+ω decays are observed for the first time.
Using a total of 5.25 fb−1 of e+e− collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the process e+e−→ηψ(2S) with a statistical significance of 5σ. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.
Using a sample of 1.31×109 J/ψ events collected with the BESIII detector, we perform a study of J/ψ→γηηη′ to search for the X(2370) and ηc in the ηηη′ invariant mass distribution. No significant signal for the X(2370) is observed, and we set an upper limit for the product branching fraction of B(J/ψ→γX(2370)⋅B(X(2370)→ηηη′)<9.2×10−6 at the 90% confidence level. A clear ηc signal is observed for the first time, yielding a product branching fraction of B(J/ψ→γηc)⋅B(ηc→ηηη′)=(4.86±0.62 (stat.)±0.45 (sys.))×10−5.
Using a sample of 1.31×109 J/ψ events collected with the BESIII detector at the electron-positron collider BEPCII, we analyse the full J/ψ→ Ξ−Ξ+, Ξ−→Λπ−, Λ→pπ−, Ξ+→Λπ+, Λ→pπ+ decay chain. A new method, exploiting the fact that the Ξ−Ξ+ pair is entangled and sequentially decaying, and where the complete decay chains are reconstructed, is applied for the first time. This enables precision measurements of the decay parameters for the Ξ−→Λπ− decay (αΞ, ϕΞ) as well as the Ξ+→Λπ+ decay (αΞ, ϕΞ). From the decay parameters, two independent CP tests were performed, quantified by the observables ACPΞ and ΔϕΞ. Our results, ACPΞ = (6.0±13.4±5.6)×10−3 and ΔϕΞ=(−4.8±13.7±2.9)×10−3 rad, are consistent with CP symmetry. Furthermore, our method enables a separation of strong and weak Ξ→Λπ decay amplitudes. This results in the first direct measurement of the weak phase difference for any baryon decay. The result is found to be (ξP−ξS)=(1.2±3.4±0.8)×10−2 rad and is one of the most precise tests of CP symmetry for strange baryons. The strong phase difference is measured to be (δP−δS)=(−4.0±3.3±1.7)×10−2 rad. In addition, we provide an independent measurement of the recently debated Λ decay parameter, αΛ=0.757±0.011±0.008. The ΛΛ asymmetry is measured to be ACPΛ=(−3.7±11.7±9.0)×10−3.
From 1310.6×106 J/ψ and 448.1×106 ψ(3686) events collected with the BESIII experiment, we report the first observation of Σ+ and Σˉ− spin polarization in e+e−→J/ψ(ψ(3686))→Σ+Σˉ− decays. The relative phases of the form factors ΔΦ have been measured to be (−15.5±0.7±0.5)∘ and (21.7±4.0±0.8)∘ with J/ψ and ψ(3686) data, respectively. The non-zero value of ΔΦ allows for a direct and simultaneous measurement of the decay asymmetry parameters of Σ+→pπ0 (α0=−0.998±0.037±0.009) and Σˉ−→pˉπ0 (αˉ0=0.990±0.037±0.011), the latter value being determined for the first time. The average decay asymmetry, (α0−αˉ0)/2, is calculated to be −0.994±0.004±0.002. The CP asymmetry ACP,Σ=(α0+αˉ0)/(α0−αˉ0)=−0.004±0.037±0.010 is extracted for the first time, and is found to be consistent with CP conservation.
This work presents a novel ensemble of Bayesian Neural Networks (BNNs) for control of safety-critical systems. Decision making for safety-critical systems is challenging due to performance requirements with significant consequences in the event of failure. In practice, failure of such systems can be avoided by introducing redundancies of control. Neural Networks (NNs) are generally not used for safety-critical systems as they can behave in unexpected ways in response to novel inputs. In addition, there may not be any indication as to when they will fail. BNNs have been recognized for their ability to produce not only viable outputs but also provide a measure of uncertainty in these outputs. This work combines the knowledge of prediction uncertainty obtained from BNNs and ensemble control for a redundant control methodology. Our technique is applied to an agile autonomous driving task. Multiple BNNs are trained to control a vehicle in an end-to-end fashion on different sensor inputs provided by the system. We show that an individual network is successful in maneuvering around the track but crashes in the presence of unforeseen input noise. Our proposed ensemble of BNNs shows successful task performance even in the event of multiple sensor failures.
Non-volatile flip-flops (NVFFs) using power gating techniques promise to overcome the soaring leakage power consumption issue with the scaling of CMOS technology. Magnetic tunnel junction (MTJ) is a good candidate for constructing the NVFF thanks to its low power, high speed, good CMOS compatibility, etc. In this paper, we propose a novel magnetic NVFF based on an emerging memory device called NAND-SPIN. The data writing of NAND-SPIN is achieved by successively applying two unidirectional currents, which respectively generate the spin orbit torque (SOT) and spin transfer torque (STT) for erase and programming operations. This characteristic allows us to design an erase-hidden and drivability-improved magnetic NVFF. Furthermore, more design flexibility could be obtained since the backup operation of the proposed NVFF is not limited by the inherent slave latch. Simulation results show that our proposed NVFF achieves performance improvement in terms of power, delay and area, compared with conventional slave-latch-driven SOT-NVFF designs.
In Phys. Lett. B 753, 629-638 (2016) [arXiv:1507.08188] the BESIII collaboration published a cross section measurement of the process e+e−→π+π− in the energy range between 600 and 900 MeV. In this erratum we report a corrected evaluation of the statistical errors in terms of a fully propagated covariance matrix. The correction also yields a reduced statistical uncertainty for the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, which now reads as aμππ,LO(600−900MeV)=(368.2±1.5stat±3.3syst)×10−10. The central values of the cross section measurement and of aμππ,LO, as well as the systematic uncertainties remain unchanged.
We measured the branching fractions of the decays χcJ→Σ−Σˉ+ for the first time using the final states nnˉπ+π−. The data sample exploited here is 448.1×106 ψ(3686) events collected with BESIII. We find B(χcJ→Σ−Σˉ+)=(51.3±2.4±4.1)×10−5,(5.7±1.4±0.6)×10−5,and (4.4±1.7±0.5)×10−5, for J=0,1,2, respectively, where the first uncertainties are statistical and the second systematic.
Using a sample of 106 million ψ(3686) decays, ψ(3686)→γχcJ(J=0,1,2) and ψ(3686)→γχcJ,χcJ→γJ/ψ (J=1,2) events are utilized to study inclusive χcJ→ anything, χcJ→ hadrons, and J/ψ→ anything distributions, including distributions of the number of charged tracks, electromagnetic calorimeter showers, and π0s, and to compare them with distributions obtained from the BESIII Monte Carlo simulation. Information from each Monte Carlo simulated decay event is used to construct matrices connecting the detected distributions to the input predetection "produced" distributions. Assuming these matrices also apply to data, they are used to predict the analogous produced distributions of the decay events. Using these, the charged particle multiplicities are compared with results from MARK I. Further, comparison of the distributions of the number of photons in data with those in Monte Carlo simulation indicates that G-parity conservation should be taken into consideration in the simulation.
Using 2.93 fb−1 of e+e− collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays D→ωππ to be B(D0→ωπ+π−)=(1.33±0.16±0.12)×10−3 and B(D+→ωπ+π0)=(3.87±0.83±0.25)×10−3, where the first uncertainties are statistical and the second ones systematic. The statistical significances are 12.9σ and 7.7σ, respectively. The precision of B(D0→ωπ+π−) is improved by a factor of 2.1 over the CLEO measurement, and B(D+→ωπ+π0) is measured for the first time. No significant signal of B(D0→ωπ0π0) is observed, and the upper limit on the branching fraction is B(D0→ωπ0π0)<1.10×10−3 at the 90% confidence level. The branching fractions of D→ηππ are also measured and consistent with existing results.
The processes e+e−→Ds+Ds1(2460)−+c.c. and e+e−→Ds∗+Ds1(2460)−+c.c. are studied for the first time using data samples collected with the BESIII detector at the BEPCII collider. The Born cross sections of e+e−→Ds+Ds1(2460)−+c.c. at nine center-of-mass energies between 4.467\,GeV and 4.600\,GeV and those of e+e−→Ds∗+Ds1(2460)−+c.c. at s= 4.590\,GeV and 4.600\,GeV are measured. No obvious charmonium or charmonium-like structure is seen in the measured cross sections.
Born cross sections for the processes e+e−→ωη and e+e−→ωπ0 have been determined for center-of-mass energies between 2.00 and 3.08 GeV with the BESIII detector at the BEPCII collider. The results obtained in this work are consistent with previous measurements but with improved precision. Two resonant structures are observed. In the e+e−→ωη cross sections, a resonance with a mass of (2179±21±3)MeV/c2 and a width of (89±28±5)MeV is observed with a significance of 6.1σ. Its properties are consistent with the ϕ(2170). In the e+e−→ωπ0 cross sections, a resonance denoted Y(2040) is observed with a significance of more than 10σ. Its mass and width are determined to be (2034±13±9)MeV/c2 and (234±30±25)MeV, respectively, where the first uncertainties are statistical and the second ones are systematic.
The process e+e−→ϕη′ has been studied for the first time in detail using data sample collected with the BESIII detector at the BEPCII collider at center of mass energies from 2.05 to 3.08 GeV. A resonance with quantum numbers JPC=1−− is observed with mass M = (2177.5 ± 4.8 (stat) ± 19.5 (syst)) MeV/c2 and width Γ = (149.0 ± 15.6 (stat) ± 8.9 (syst)) MeV with a statistical significance larger than 10σ. The observed structure could be identified with the ϕ(2170), then the ratio of partial width between the ϕη′ by BESIII and ϕη by BABAR is (BϕηRΓeeR)/(Bϕη′RΓeeR) = 0.23 ± 0.10 (stat) ± 0.18 (syst), which is smaller than the prediction of the ssˉg hybrid models by several orders of magnitude.
The cross sections of the process e+e−→ηJ/ψ at center-of-mass energies (s) between 3.81 and 4.60 GeV are measured with high precision by using data samples collected with the BESIII detector operating at the BEPCII storage ring. Three structures are observed by analyzing the lineshape of the measured cross sections, and a maximum-likelihood fit including three resonances is performed by assuming the lowest lying structure is the ψ(4040). For the other resonances, we obtain masses of (4218.7±4.0±2.5) and (4380.4±14.2±1.8) MeV/c2 with corresponding widths of (82.5±5.9±0.5) and (147.0±63.0±25.8) MeV, respectively, where the first uncertainties are statistical and the second ones systematic. The measured resonant parameters are consistent with those of the Y(4220) and Y(4360) from pr evious measurements of different final states. For the first time, we observe the decays of the Y(4220) and Y(4360) into ηJ/ψ final states.
This paper introduces a new formulation for stochastic optimal control and stochastic dynamic optimization that ensures safety with respect to state and control constraints. The proposed methodology brings together concepts such as Forward-Backward Stochastic Differential Equations, Stochastic Barrier Functions, Differentiable Convex Optimization and Deep Learning. Using the aforementioned concepts, a Neural Network architecture is designed for safe trajectory optimization in which learning can be performed in an end-to-end fashion. Simulations are performed on three systems to show the efficacy of the proposed methodology.
Ten hadronic final states of the hc decays are investigated via the process ψ(3686)→π0hc, using a data sample of (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector. The decay channel hc→K+K−π+π−π0 is observed for the first time with a significance of 6.0σ. The corresponding branching fraction is determined to be B(hc→K+K−π+π−π0)=(3.3±0.6±0.6)×10−3 (the first uncertainty is statistical and the second systematical). Evidence for the decays hc→π+π−π0η and hc→KS0K±π∓π+π− is found with a significance of 3.6σ and 3.8σ, respectively. The corresponding branching fractions (and upper limits) are obtained to be B(hc→π+π−π0η)=(7.2±1.8±1.3)×10−3 (<1.8×10−2) and B(hc→KS0K±π∓π+π−)=(2.8±0.9±0.5)×10−3 (<4.7×10−3). Upper limits on the branching fractions for the final states hc→K+K−π0, K+K−η, K+K−π+π−η, 2(K+K−)π0, K+K−π0η, KS0K±π∓, and ppˉπ0π0 are determined at a confidence level of 90\%.
We search for J/ψ radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the J/ψ produced through the process ψ(3686)→π+π−J/ψ in a data sample of (448.1±2.9)×106 ψ(3686) decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2 GeV/c2. The upper limit corresponding to an invisible particle with zero mass is 7.0×10−7 at the 90\% confidence level.
Using 2.93 fb−1 of e+e− annihilation data collected at a center-of-mass energy s=3.773 GeV with the BESIII detector operating at the BEPCII collider, we search for the semileptonic D0(+) decays into a b1(1235)−(0) axial-vector meson for the first time. No significant signal is observed for either charge combination. The upper limits on the product branching fractions are BD0→b1(1235)−e+νe⋅Bb1(1235)−→ωπ−<1.12×10−4 and BD+→b1(1235)0e+νe⋅Bb1(1235)0→ωπ0<1.75×10−4 at the 90\% confidence level.
Using a dedicated data sample taken in 2018 on the J/ψ peak, we perform a detailed study of the trigger efficiencies of the BESIII detector. The efficiencies are determined from three representative physics processes, namely Bhabha-scattering, dimuon production and generic hadronic events with charged particles. The combined efficiency of all active triggers approaches 100% in most cases with uncertainties small enough as not to affect most physics analyses.
The processes X(3872)→D∗0D0ˉ+c.c., γJ/ψ, γψ(2S), and γD+D− are searched for in a 9.0 fb−1 data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872)→D∗0D0ˉ+c.c. and find evidence for X(3872)→γJ/ψ with statistical significances of 7.4σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD+D− are found, and upper limit on the relative branching ratio Rγψ≡B(X(3872)→γJ/ψ)B(X(3872)→γψ(2S))<0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π+π−J/ψ are also reported for decays X(3872)→D∗0D0ˉ+c.c., γψ(2S), γJ/ψ, γD+D−, as well as the non-D∗0Dˉ0 three-body decays π0D0Dˉ0 and γD0Dˉ0.
By using phase retrieval, Bragg Coherent Diffractive Imaging (BCDI) allows tracking of three-dimensional displacement fields inside individual nanocrystals. Nevertheless, in the presence of significant (1% and higher) strains, such as in the process of a structural phase transformation, fails due to the Bragg peak distortions. Here we present an advanced BCDI algorithm enabling imaging three-dimensional strain fields in highly strained crystals. We test the algorithm on particles simulated to undergo a structural phase transformation. While the conventional algorithm fails in unambiguously reconstructing the phase morphology, our algorithm correctly retrieves the morphology of coexistent phases with a strain difference of 1%. The key novelty is the simultaneous reconstruction of multiple scans of the same nanoparticle at snapshots through the phase transformations. The algorithm enables visualizing phase transformations in nanoparticles of lithium-ion, sodium-ion nanoparticles, and other nanoparticulate materials in working conditions (operando).
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