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Yang Gao

Publications and source records attributed to Yang Gao.

At least 505 records · Page 28Linked to original sources
arXiv2023

Measurement of the $e^{+}e^{-}\rightarrowωπ^{0}π^{0}$ cross section at center-of-mass energies from 2.0 to 3.08 GeV

The cross section of the process $e^{+}e^{-}\toωπ^{0}π^{0}$ is measured at nineteen center-of-mass energies from 2.0 to 3.08 GeV using data collected with the BESIII detector at the BEPCII storage ring. A resonant structure around 2.20 GeV is observed with statistical significance larger than $5σ$. Using a coherent fit to the cross section line shape, the mass and width are determined to be $M=2222\pm7\pm2~{\rm MeV}/c^2$ and $\varGamma=59\pm30\pm6~{\rm MeV}$, respectively, where the first uncertainties are statistical and the second ones are systematic.

hep-ex↗
arXiv2023

Tests of $CP$ symmetry in the entangled $Ξ^0-\barΞ^0$ Pairs

The $J/ψ\to Ξ^0 \barΞ^{0}$ process and subsequent decays are investigated using $(10087 \pm 44)\times 10^6$ $J/ψ$ events collected at the BESIII experiment. The decay parameters of $Ξ^0$ and $\barΞ^0$ are measured with greatly improved precision over previous measurements to be $α_Ξ = -0.3750 \pm 0.0034 \pm 0.0016$, $\barα_Ξ = 0.3790 \pm 0.0034 \pm 0.0021$, $ϕ_Ξ = 0.0051 \pm 0.0096 \pm 0.0018$~rad, $\barϕ_Ξ = -0.0053 \pm 0.0097 \pm 0.0019$~rad, where the first and the second uncertainties are statistical and systematic, respectively. From these measurements, precise $CP$ symmetry tests in $Ξ^0$ decay are performed, and $A^Ξ_{CP} = (-5.4 \pm 6.5 \pm 3.1) \times 10^{-3}$ and $Δϕ^Ξ_{CP} = (-0.1 \pm 6.9 \pm 0.9) \times 10^{-3}$~rad are consistent with $CP$ conservation. The sequential decay also enables a separation of weak and strong phase differences, which are found for the first time to be $ξ_{P}-ξ_{S} = (0.0 \pm 1.7 \pm 0.2) \times 10^{-2}$~rad and $δ_{P}-δ_{S} = (-1.3 \pm 1.7 \pm 0.4)\times 10^{-2}$~rad, respectively. In addition, we measure the $Λ$ decay parameters and test $CP$ symmetry in $Λ$ decays.

hep-ex↗
arXiv2023

Search for the lepton number violation decay $ϕ\to π^+ π^+ e^- e^-$ via $J/ψ\to ϕη$

Using $(1.0087\pm0.0044)\times10^{10}$ $J/ψ$ events collected by the BESIII detector at the BEPCII collider, we search for the lepton number violation decay $ϕ\to π^+ π^+ e^- e^-$ via $J/ψ\to ϕη$. No signal is found and the upper limit on the branching fraction of $ϕ\to π^+ π^+ e^- e^-$ is set to be $9.7\times10^{-6}$ at the 90\% confidence level.

hep-ex↗
arXiv2023

Measurement of the $e^+e^- \to Λ\barΣ^0 + c.c.$ cross sections at $\sqrt{s}$ from 2.3094 to 3.0800 GeV

The Born cross sections and effective form factors of the process $e^+e^-\toΛ\barΣ^0 + c.c.$ are measured at 14 center-of-mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of $(478.5 \pm 4.8)\ \text{pb}^{-1}$ collected with the BESIII detector. A non-zero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the BaBar Collaboration. The Born cross-section lineshape is described better by a shape with a plateau near the threshold than by a pQCD motivated functional form.

hep-ex↗
arXiv2023

Measurement of the absolute branching fraction of the inclusive decay $\barΛ_{c}^{-} \to \bar{n} + X$

Based on $e^+e^-$ collision data corresponding to an integrated luminosity of 4.5 $fb^{-1}$ collected at the center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII, the absolute branching fraction of the inclusive decay $Λ^{+}_{c}\to n + X$, where $X$ refers to any possible final state particles, is measured. The absolute branching fraction is determined to be $\mathcal{B}(Λ^{+}_{c}\to n + X) = (32.4 \pm 0.7 \pm 1.5)\% $, where the first uncertainty is statistical and the second systematic. Assuming $CP$ symmetry, the measurement indicates that about one-fourth of $Λ^{+}_{c}$ ($\barΛ_{c}^-$) decay modes with a neutron (an anti-neutron) in the final state have not been observed.

hep-ex↗
arXiv2023

Amplitude analysis and branching fraction measurement of the decay $D^{+} \to K_S^0π^+π^0π^0$

Using 2.93 $\rm{fb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at the center-of-mass energy 3.773\,GeV, we perform the first amplitude analysis of the decay $D^+\to K_S^0π^+π^0π^0$ and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of $D^+\to K_S^0π^+π^0π^0$ is measured to be $(2.888\pm0.058_{\rm stat.}\pm0.069_{\rm syst.})\%$. The dominant intermediate processes are $D^+\to K_S^0a_1(1260)^+(\to ρ^+π^0)$ and $D^+\to \bar{K}^{*0}ρ^+$, with branching fractions of $(8.66\pm1.04_{\rm stat.}\pm1.39_{\rm syst.})\!\times \!10^{-3}$ and $(9.70\pm0.81_{\rm stat.}\pm0.53_{\rm syst.})\!\times \!10^{-3}$, respectively.

hep-ex↗
arXiv2023

Where and How: Mitigating Confusion in Neural Radiance Fields from Sparse Inputs

Neural Radiance Fields from Sparse input} (NeRF-S) have shown great potential in synthesizing novel views with a limited number of observed viewpoints. However, due to the inherent limitations of sparse inputs and the gap between non-adjacent views, rendering results often suffer from over-fitting and foggy surfaces, a phenomenon we refer to as "CONFUSION" during volume rendering. In this paper, we analyze the root cause of this confusion and attribute it to two fundamental questions: "WHERE" and "HOW". To this end, we present a novel learning framework, WaH-NeRF, which effectively mitigates confusion by tackling the following challenges: (i)"WHERE" to Sample? in NeRF-S -- we introduce a Deformable Sampling strategy and a Weight-based Mutual Information Loss to address sample-position confusion arising from the limited number of viewpoints; and (ii) "HOW" to Predict? in NeRF-S -- we propose a Semi-Supervised NeRF learning Paradigm based on pose perturbation and a Pixel-Patch Correspondence Loss to alleviate prediction confusion caused by the disparity between training and testing viewpoints. By integrating our proposed modules and loss functions, WaH-NeRF outperforms previous methods under the NeRF-S setting. Code is available https://github.com/bbbbby-99/WaH-NeRF.

cs.CV↗
arXiv2023

cuQuantum SDK: A High-Performance Library for Accelerating Quantum Science

We present the NVIDIA cuQuantum SDK, a state-of-the-art library of composable primitives for GPU-accelerated quantum circuit simulations. As the size of quantum devices continues to increase, making their classical simulation progressively more difficult, the availability of fast and scalable quantum circuit simulators becomes vital for quantum algorithm developers, as well as quantum hardware engineers focused on the validation and optimization of quantum devices. The cuQuantum SDK was created to accelerate and scale up quantum circuit simulators developed by the quantum information science community by enabling them to utilize efficient scalable software building blocks optimized for NVIDIA GPU platforms. The functional building blocks provided cover the needs of both state vector- and tensor network- based simulators, including approximate tensor network simulation methods based on matrix product state, projected entangled pair state, and other factorized tensor representations. By leveraging the enormous computing power of the latest NVIDIA GPU architectures, quantum circuit simulators that have adopted the cuQuantum SDK demonstrate significant acceleration, compared to CPU-only execution, for both the state vector and tensor network simulation methods. Furthermore, by utilizing the parallel primitives available in the cuQuantum SDK, one can easily transition to distributed GPU-accelerated platforms, including those furnished by cloud service providers and high-performance computing systems deployed by supercomputing centers, extending the scale of possible quantum circuit simulations. The rich capabilities provided by the SDK are conveniently made available via both Python and C application programming interfaces, where the former is directly targeting a broad Python quantum community and the latter allows tight integration with simulators written in any programming language.

quant-ph↗
arXiv2023

DePA: Improving Non-autoregressive Machine Translation with Dependency-Aware Decoder

Non-autoregressive machine translation (NAT) models have lower translation quality than autoregressive translation (AT) models because NAT decoders do not depend on previous target tokens in the decoder input. We propose a novel and general Dependency-Aware Decoder (DePA) to enhance target dependency modeling in the decoder of fully NAT models from two perspectives: decoder self-attention and decoder input. First, we propose an autoregressive forward-backward pre-training phase before NAT training, which enables the NAT decoder to gradually learn bidirectional target dependencies for the final NAT training. Second, we transform the decoder input from the source language representation space to the target language representation space through a novel attentive transformation process, which enables the decoder to better capture target dependencies. DePA can be applied to any fully NAT models. Extensive experiments show that DePA consistently improves highly competitive and state-of-the-art fully NAT models on widely used WMT and IWSLT benchmarks by up to 1.88 BLEU gain, while maintaining the inference latency comparable to other fully NAT models.

cs.CL↗
arXiv2023

Measurement of the absolute branching fraction of the inclusive decay $D_s^+\to π^+π^+π^- X$

Using an $e^+ e^-$ collision data sample with a total integrated luminosity of $3.19$ fb$^{-1}$ collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the inclusive decay of the $D_s^+$ meson to final states including at least three charged pions is measured for the first time to be ${\cal B}(D_s^+\toπ^+ π^+ π^- X) = (32.81 \pm 0.35_{\rm stat} \pm {0.63_{\rm syst}})\%$. In this measurement the charged pions from $K_S^0$ meson decays are excluded. The partial branching fractions of $D_s^+\toπ^+ π^+ π^- X$ are also measured as a function of the $π^+ π^+ π^-$ invariant mass.

hep-ex↗
arXiv2023

Measurement of the $C\!P$-even fraction of $D^0\to K^+K^-π^+π^-$

A determination of the $C\!P$-even fraction $F_+$ in the decay $D^0 \to K^+K^-π^+π^-$ is presented. Using $2.93$ fb$^{-1}$ of $e^+e^-\toψ(3770)\to D\bar{D}$ data collected by the BESIII detector, one charm meson is reconstructed in the signal mode and the other in a $C\!P$ eigenstate or the decay $D\to K_{S, L}^0π^+π^-$. Analysis of the relative rates of these double-tagged events yields the result $F_+ = 0.730 \pm 0.037 \pm 0.021$, where the first uncertainty is statistical and the second is systematic. This is the first model-independent measurement of $F_+$ in $D^0 \to K^+K^-π^+π^-$ decays.

hep-ex↗
arXiv2023

3D Medical Image Segmentation with Sparse Annotation via Cross-Teaching between 3D and 2D Networks

Medical image segmentation typically necessitates a large and precisely annotated dataset. However, obtaining pixel-wise annotation is a labor-intensive task that requires significant effort from domain experts, making it challenging to obtain in practical clinical scenarios. In such situations, reducing the amount of annotation required is a more practical approach. One feasible direction is sparse annotation, which involves annotating only a few slices, and has several advantages over traditional weak annotation methods such as bounding boxes and scribbles, as it preserves exact boundaries. However, learning from sparse annotation is challenging due to the scarcity of supervision signals. To address this issue, we propose a framework that can robustly learn from sparse annotation using the cross-teaching of both 3D and 2D networks. Considering the characteristic of these networks, we develop two pseudo label selection strategies, which are hard-soft confidence threshold and consistent label fusion. Our experimental results on the MMWHS dataset demonstrate that our method outperforms the state-of-the-art (SOTA) semi-supervised segmentation methods. Moreover, our approach achieves results that are comparable to the fully-supervised upper bound result.

cs.CV↗
arXiv2023

Efficient Exploration Using Extra Safety Budget in Constrained Policy Optimization

Reinforcement learning (RL) has achieved promising results on most robotic control tasks. Safety of learning-based controllers is an essential notion of ensuring the effectiveness of the controllers. Current methods adopt whole consistency constraints during the training, thus resulting in inefficient exploration in the early stage. In this paper, we propose an algorithm named Constrained Policy Optimization with Extra Safety Budget (ESB-CPO) to strike a balance between the exploration efficiency and the constraints satisfaction. In the early stage, our method loosens the practical constraints of unsafe transitions (adding extra safety budget) with the aid of a new metric we propose. With the training process, the constraints in our optimization problem become tighter. Meanwhile, theoretical analysis and practical experiments demonstrate that our method gradually meets the cost limit's demand in the final training stage. When evaluated on Safety-Gym and Bullet-Safety-Gym benchmarks, our method has shown its advantages over baseline algorithms in terms of safety and optimality. Remarkably, our method gains remarkable performance improvement under the same cost limit compared with baselines.

cs.RO↗
arXiv2023

Observation of the decay $J/ψ\to e^+ e^- η(1405)$ with $η(1405) \to π^0 f_0(980)$

Using a data sample of $(10087\pm44)\times 10^6$ $J/ψ$ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process $J/ψ\to e^+ e^- η(1405)$ is observed via the decay $η(1405) \to π^0 f_0(980)$, $f_0(980) \to π^+ π^-$, with a significance of about $9.6σ$. The branching fraction of this decay is measured to be ${\mathcal B}(J/ψ\to e^+ e^- π^0 η(1405) \to e^+ e^- π^0 f_0(980) \to e^+ e^- π^0 π^+ π^-)=(2.02\pm0.24(\rm{stat.})\pm0.09(\rm{syst.}))\times 10^{-7}$. The branching-fraction ratio ${\mathcal B}(J/ψ\to e^+ e^- η(1405))$/${\mathcal B}(J/ψ\to γη(1405))$ is determined to be $(1.35\pm0.19(\rm{stat.})\pm0.06(\rm{syst.}))\times10^{-2}$. Furthermore, an $e^+e^-$ invariant-mass dependent transition form factor of $J/ψ\to e^+ e^-η(1405)$ is presented for the first time. The obtained result provides input for different theoretical models, and is valuable for the improved understanding the intrinsic structure of the $η(1405)$ meson.

hep-ex↗
arXiv2023

Studies of the decay $D^+_s\to K^+K^- μ^+ ν_μ$

The $D^+_s\to K^+K^-μ^+ν_μ$ decay is studied based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at center-of-mass energies in the range from 4.128 to 4.226 GeV. The absolute branching fraction is measured as ${\mathcal B}(D^+_s\to ϕμ^+ν_μ) = (2.25\pm 0.09 \pm 0.07) \times10^{-2}$, the most precise measurement to date. Combining with the world average of ${\mathcal B}(D^+_s\to ϕe^+ν_e)$, the ratio of the branching fractions obtained is$\frac{{\mathcal B}(D^+_s\to ϕμ^+ν_μ)}{{\mathcal B}(D^+_s\to ϕe^+ν_e)} = 0.94\pm0.08$, in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios at $q^{2}=0$ are extracted, finding $r_{V}=\frac{V(0)}{A_{1}(0)}=1.58\pm0.17\pm0.02$ and $r_{2}=\frac{A_{2}(0)}{A_{1}(0)}=0.71\pm0.14\pm0.02$, where the first uncertainties are statistical and the second are systematic. No significant $S$-wave contribution from $f_0(980)\to K^+K^-$ is found. The upper limit $\mathcal{B}(D_s^+\to f_0(980)μ^{+}ν_μ) \cdot{\mathcal B}(f_0(980)\to K^+K^-) < 5.45 \times 10^{-4}$ is set at 90\% confidence level.

hep-ex↗
arXiv2023

Production of doubly-charged $Δ$ baryon in $e^{+}e^{-}$ annihilation at energies from 2.3094 to 2.6464 GeV

The processes $e^{+}e^{-} \to Δ^{++}\barΔ^{--}$ and $e^{+}e^{-}\to Δ^{++} \bar{p} π^{-} + c.c.$ are studied for the first time with $179~{\rm pb}^{-1}$ of $e^{+}e^{-}$ annihilation data collected with the BESIII detector at center-of-mass energies from $2.3094$ GeV to $2.6464$ GeV. No significant signal for the $e^{+}e^{-}\to Δ^{++}\barΔ^{--}$ process is observed and the upper limit of the Born cross section is estimated at each energy point. For the process $e^{+}e^{-} \to Δ^{++} \bar{p} π^{-} + c.c.$, a significant signal is observed at center-of-mass energies near 2.6454 GeV and the corresponding Born cross section is reported.

hep-ex↗
arXiv2023

Measurement of the Energy-Dependent Electromagnetic Form Factors of a Charmed Baryon

We study the process $e^{+}e^{-}\toΛ_{c}^{+}\barΛ_c^{-}$ at twelve center-of-mass energies from $4.6119$ to $4.9509~\mathrm{GeV}$ using data samples collected by the BESIII detector at the BEPCII collider. The Born cross sections and effective form factors ($|G_{\mathrm{eff}}|$) are determined with unprecedented precision after combining the single and double-tag methods based on the decay process $Λ_{c}^{+}\to pK^{-}π^{+}$. Flat cross sections around $4.63~\mathrm{GeV}$ are obtained and no indication of the resonant structure $Y(4630)$, as reported by Belle, is found. In addition, no oscillatory behavior is discerned in the $|G_{\mathrm{eff}}|$ energy-dependence of $Λ_{c}^{+}$, in contrast to what is seen for the proton and neutron cases. Analyzing the cross section together with the polar-angle distribution of the $Λ_{c}^{+}$ baryon at each energy point, the moduli of electric and magnetic form factors ($|G_{E}|$ and $|G_{M}|$) are extracted and separated. For the first time, the energy-dependence of the form factor ratio $|G_{E}/G_{M}|$ is observed, which can be well described by an oscillatory function.

hep-ex↗
arXiv2023

First simultaneous measurement of $Ξ^0$ and $\barΞ^0$ asymmetry parameters in $ψ(3686)$ decay

The $Ξ^0$ asymmetry parameters are measured using entangled quantum $Ξ^0$-$\barΞ^0$ pairs from a sample of $(448.1 \pm 2.9) \times 10^6$ $ψ(3686)$ events collected with the BESIII detector at BEPCII. The relative phase between the transition amplitudes of the $Ξ^0 \barΞ^0$ helicity states is measured to be $ΔΦ= -0.050 \pm 0.150 \pm 0.020$~rad, which implies that there is no obvious polarization at the current level of statistics. The decay parameters of the $Ξ^0$ hyperon $(α_{Ξ^0}, α_{\barΞ^0}, ϕ_{Ξ^0}, ϕ_{\barΞ^0})$ and the angular distribution parameter $(α_{ψ(3686)})$ and $ΔΦ$ are measured simultaneously for the first time. In addition, the $CP$ asymmetry observables are determined to be $A^{Ξ^0}_{CP} = (α_{Ξ^0} + α_{\barΞ^0})/(α_{Ξ^0} - α_{\barΞ^0})$ $= -0.007$ $\pm$ 0.082 $\pm$ 0.025 and $Δϕ^{Ξ^0}_{CP} = (ϕ_{Ξ^0} + ϕ_{\barΞ^0})/2$ $= -0.079$ $\pm$ 0.082 $\pm$ 0.010 rad, which are consistent with $CP$ conservation.

hep-ex↗