4,337 research outputs found

    Semi-inclusive decays of BB meson into a dark anti-baryon and baryons

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    Using the recently developed BB-Mesogenesis scenario, we studied the semi-inclusive decays of BB meson into a dark anti-baryon ψ\psi plus any possible states XX containing u/cu/c and d/sd/s quarks with unit baryon number. The two types of effective Lagrangians proposed by the scenario are both considered in the study. The semi-inclusive decay branching fractions of B→XψB\to X \psi are calculated by the method of heavy quark expansion, where the non-perturbative contributions from the matrix elements of dimension-5 operators are included. We obtained the branching fractions as functions of the dark anti-baryon mass. Using the experimental upper limits of the branching fractions, we presented the constraints of the coupling constants in the BB-Mesogenesis scenario.Comment: 17 pages, 4 figures and 1 tabl

    Anomalous dimensions for the interpolating currents of baryons

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    The anomalous dimensions for the interpolating currents of baryons are indispensable inputs in a serious analysis of baryon QCD sum rules. However, the results in the literature are vague. In view of this, in this work, we investigate the one-loop anomalous dimensions for some interpolating currents such as those of ΛQ\Lambda_{Q} and proton. This work has more significance in pedagogy.Comment: 5 pages, 1 figur

    A novel method for searching the Ξc0/+\Xi_c^{0/+}-Ξc′0/+\Xi_c^{\prime 0/+} mixing effect in the angular distribution analysis of a four-body Ξc0/+\Xi_c^{0/+} decay

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    In this work, we raised a novel method for searching the Ξc0+\Xi^{0+}_c-Ξc0+′\Xi_c^{0+\prime} mixing effect in an angular distribution analysis of the Ξc→Ξ(′)(Λπ)ℓ+ν\Xi_c\to\Xi^{(\prime)}(\Lambda \pi)\ell^+\nu decay, where the mixing effect can be observed by the appearance of the Ξ′\Xi^{\prime} resonant. Armed with this angular distribution, the decay branching fraction and the forward-backward asymmetry are predicted. We pointed out that the forward-backward asymmetry, as a function of the invariant mass square of Ξ(′)\Xi^{(\prime)} and the Ξc0+\Xi^{0+}_c-Ξc0+′\Xi_c^{0+\prime} mixing angle θc\theta_c, can be used to distinguish the two resonants Ξ(′)\Xi^{(\prime)} and even provide a possibility to determine the exact mixing angle.Comment: 7 pages, 3 figure

    Light baryon in three quark picture light front approach and its application: hyperon weak radiative decays

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    Motivated by recent experimental data on Σ+→pγ\Sigma^+\to p\gamma at BESIII, we investigate a class of hyperon weak radiative decays. To estimate these processes, in our research, we employ a new type of light-front quark model with a three-quark picture for octet baryons. In the three-quark picture, with the use of SU(3)fSU(3)_f and spin symmetries, we present a general form of the light front wave function for each octet baryon. By including contributions from the penguin diagram and W exchange diagram, we perform a complete calculation on the branching ratios (BrBr) and the asymmetry parameter (α\alpha) for hyperon weak radiative decay processes. Our results are helpful for discovering additional hyperon weak radiative decay processes in experimental facilities, and our research will promote the theoretical study of baryons.Comment: 15 pages, 2 figures, 5 table

    Ionic effect on combing of single DNA molecules and observation of their force-induced melting by fluorescence microscopy

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    Molecular combing is a powerful and simple method for aligning DNA molecules onto a surface. Using this technique combined with fluorescence microscopy, we observed that the length of lambda-DNA molecules was extended to about 1.6 times their contour length (unextended length, 16.2 micrometers) by the combing method on hydrophobic polymethylmetacrylate (PMMA) coated surfaces. The effects of sodium and magnesium ions and pH of the DNA solution were investigated. Interestingly, we observed force-induced melting of single DNA molecules.Comment: 12 page

    k-semistratifiable spaces and expansions of set-valued mappings

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    [EN] In this paper, the concept of k-upper semi-continuous set-valued mappings is introduced. Using this concept, we give characterizations of k-semistratifiable and k-MCM spaces, which answers a question posed by Xie and Yan.Yan, P.; Hu, X.; Xie, L. (2018). k-semistratifiable spaces and expansions of set-valued mappings. Applied General Topology. 19(1):145-153. doi:10.4995/agt.2018.7883SWORD14515319

    When Prompt-based Incremental Learning Does Not Meet Strong Pretraining

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    Incremental learning aims to overcome catastrophic forgetting when learning deep networks from sequential tasks. With impressive learning efficiency and performance, prompt-based methods adopt a fixed backbone to sequential tasks by learning task-specific prompts. However, existing prompt-based methods heavily rely on strong pretraining (typically trained on ImageNet-21k), and we find that their models could be trapped if the potential gap between the pretraining task and unknown future tasks is large. In this work, we develop a learnable Adaptive Prompt Generator (APG). The key is to unify the prompt retrieval and prompt learning processes into a learnable prompt generator. Hence, the whole prompting process can be optimized to reduce the negative effects of the gap between tasks effectively. To make our APG avoid learning ineffective knowledge, we maintain a knowledge pool to regularize APG with the feature distribution of each class. Extensive experiments show that our method significantly outperforms advanced methods in exemplar-free incremental learning without (strong) pretraining. Besides, under strong retraining, our method also has comparable performance to existing prompt-based models, showing that our method can still benefit from pretraining. Codes can be found at https://github.com/TOM-tym/APGComment: Accepted to ICCV 202
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