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Gang Hao

Publications and source records attributed to Gang Hao.

9 recordsLinked to original sources

WRT-SAM: Foundation Model-Driven Segmentation for Generalized Weld Radiographic Testing

Radiographic testing is a fundamental non-destructive evaluation technique for identifying weld defects and assessing quality in industrial applications due to its high-resolution imaging capabilities. Over the past decade, deep learning techniques have significantly advanced weld defect identification in radiographic images. However, conventional approaches, which rely on training small-scale, task-specific models on single-scenario datasets, exhibit poor cross-scenario generalization. Recently, the Segment Anything Model (SAM), a pre-trained visual foundation model trained on large-scale datasets, has demonstrated exceptional zero-shot generalization capabilities. Fine-tuning SAM with limited domain-specific data has yielded promising results in fields such as medical image segmentation and anomaly detection. To the best of our knowledge, this work is the first to introduce SAM-based segmentation for general weld radiographic testing images. We propose WRT-SAM, a novel weld radiographic defect segmentation model that leverages SAM through an adapter-based integration with a specialized prompt generator architecture. To improve adaptability to grayscale weld radiographic images, we introduce a frequency prompt generator module, which enhances the model's sensitivity to frequency-domain information. Furthermore, to address the multi-scale nature of weld defects, we incorporate a multi-scale prompt generator module, enabling the model to effectively extract and encode defect information across varying scales. Extensive experimental evaluations demonstrate that WRT-SAM achieves a recall of 78.87%, a precision of 84.04%, and an AUC of 0.9746, setting a new state-of-the-art (SOTA) benchmark. Moreover, the model exhibits superior zero-shot generalization performance, highlighting its potential for practical deployment in diverse radiographic testing scenarios.

cs.CV

Determining $1^{--}$ Heavy Hybrid Masses via QCD Sum Rules

The masses of $1^{--}$ charmonium and bottomonium hybrids are evaluated in terms of QCD sum rules. We find that the ground state hybrid in charm sector lies in $m_{H_c}=4.12\sim 4.79$ GeV, while in bottom sector the hybrid may situated in $m_{H_b} = 10.24\sim 11.15$ GeV. Since the numerical result on charmonium hybrid mass is not compatible with the charmonium spectra, including structures newly observed in experiment, we tempt to conclude that such a hybrid does not purely exist, but rather as an admixture with other states, like glueball and regular quarkonium, in experimental observation. However, our result on bottomonium hybrid coincide with the "exotic structure" recently observed at BELLE.

hep-ph

Pseudoscalar Quarkonium Exclusive Decays to Vector Meson Pair

The pseudoscalar quarkonia exclusive decays to light mesons still poses a challenge to the theoretical understanding of quarkonium properties in decay. In this work, we evaluate the processes of pseudoscalar heavy quarkonium decays into vector meson pairs, especially the helicity suppressed processes of $η_b\rightarrow J/ψJ/ψ$ and $η_c\rightarrow VV$. In the frame of NRQCD, the branching fraction of $Br[η_b\rightarrow J/ψJ/ψ]$ are evaluated at the next-to-leading order of perturbative QCD; and within the light-cone distribution formalism, we calculate also the higher twist effects in these processes. Numerical results show that the higher twist terms contribute more than what from the NLO QCD corrections in the process of $η_b\rightarrow J/ψJ/ψ$. It is found that the experimental results on $η_c\rightarrow VV$ are hard to be understood by merely the quark model and perturbative QCD calculation.

hep-ph

The Fragmentation Function of Gluon Splitting into P-wave Spin-singlet Heavy Quarkonium

The gluon fragmentation function of $g \to h_c$ at leading order of strong coupling constant $α_s$ and typical velocity $v$ is calculated in the framework of NRQCD, of which the contributions from both color-singlet and -octet processes are taken into account and hence the result is infrared safe. It is found that the fragmentation probability of a high energy virtual gluon to split into $h_c$ is about $7.1\times 10^{-7}$. The analytic fragmentation function presented in this work can be employed to the study of $h_c$ production in large transverse momentum at hadron colliders, such as Large Hadron Collider(LHC), and is also applicable for the study of $h_b$ hadronproduction.

hep-ph

Investigation of the bottomonium ground state η_b via its inclusive charm decays

Based on the non-relativistic QCD factorization formalism, we calculate the bottomonium ground state, $η_b$, inclusive charm decays at the leading order in the strong coupling constant $α_s$ and quarkonium internal relative velocity $v$. The inclusive charm pair production in $η_b$ decay is mainly realized through $η_b \to c \bar{c} g$ process, where the charm and anti-charm quarks then dominantly hadronize into charmed hadrons. The momentum distributions of the final states are presented. In this work, we also calculate the $J/ψ$ inclusive production rate in the $η_b$ decays, where the color-octet contribution is found to be very important. We expect this study may shed some light on finding $η_b$ or knowing more about its nature.

hep-ph

Hunting eta_b through radiative decay into J/psi

We propose that the radiative decay process, η_b\to J/ψγ, may serve as a clean searching mode for η_b in hadron collision facilities. By a perturbative QCD calculation, we estimate the corresponding branching ratio to be of order 10^{-7}. Though very suppressed, this radiative decay channel in fact has larger branching ratio than the hadronic decay process η_b\to J/ψJ/ψ, which was previously hoped to be a viable mode for ferreting out η_b in Tevatron Run 2. The discovery potential of η_b through this channel seems promising in the forthcoming LHC experiments and maybe even in Tevatron Run 2, thanks to the huge statistics of η_b to be accumulated in these experiments. The same calculational scheme is also used to estimate the branching ratios for the processes η_b (η_c) \to ϕγ.

hep-ph

0^-+ Trigluon Glueball and its Implication for a Recent BES Observation

We calculate the mass of $0^{-+}$ triple-valence-gluon resonance, the trigluon glueball, with QCD sum rules. Its mass is found to be approximately in the region between 1.9 GeV and 2.7 GeV with some theoretical uncertainties. Moreover, it is likely that the new BES measurement of the $p \bar{p}$ enhancement near threshold in the $J/ψ$ decays exhibits the behavior of this trigluon state. Our analyzes favor the baryonium-gluonium mixing picture for the BES observation.

hep-ph

$D_s$ Asymmetry in Photoproduction

By adopting two models of strange and antistrange quark distributions inside nucleon, the light-cone meson-baryon fluctuation model and the effective chiral quark model, we calculate the $D_s^+ - D_s^-$ asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We find that the effect of asymmetry of strange sea to the $D_s$ asymmetry is considerable and depending on the different models. Therefore, we expect that with the further study in electroproduction, e.g. at HERA and CEBAF, the experimental measurements on the $D_s^+ - D_s^-$ asymmetry may impose a strong restriction on the strange-antistrange distribution asymmetry models.

hep-ph

Ds+ -- Ds- Asymmetry in Photoproduction

Considering of the possible difference in strange and antistrange quark distributions inside nucleon, we investigate the Ds+ -- Ds- asymmetry in photoproduction in the framework of heavy-quark recombination mechanism. We adopt two distribution models of strange sea, those are the light-cone meson-baryon fluctuation model and the effective chiral quark model. Our results show that the asymmetry induced by the strange quark distributions is distinct, which is measurable in experiments. And, there are evident differences between the predictions of our calculation and previous estimation. Therefore, the experimental measurements on the Ds+ -- Ds- asymmetry may impose a unique restriction on the strange-antistrange distribution asymmetry models.

hep-ph