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  1. Book ; Online: Updated analysis of $D\to PP, V\!P$ and $VV$ decays

    Cheng, Hai-Yang / Chiang, Cheng-Wei

    Implications for $K_S^0-K_L^0$ asymmetries and $D^0$-$\overline {D}^0$ mixing

    2024  

    Abstract: An updated analysis of the two-body $D\to PP, V\!P$ and $VV$ decays within the framework of the topological diagram approach is performed. A global fit to the Cabibbo-favored (CF) modes in the $V\!P$ sector gives many solutions with similarly small local ...

    Abstract An updated analysis of the two-body $D\to PP, V\!P$ and $VV$ decays within the framework of the topological diagram approach is performed. A global fit to the Cabibbo-favored (CF) modes in the $V\!P$ sector gives many solutions with similarly small local minima in $\chi^2$. The solution degeneracy is lifted once we use them to predict for the singly Cabibbo-suppressed (SCS) modes. Topological amplitudes are extracted for the $\eta-\eta'$ mixing angles $\phi=40.4^\circ$ and $43.5^\circ$. The $K_S^0-K_L^0$ asymmetries in $D\to K_{S,L}^0M$ decays denoted by $R(D,M)$ are studied. While the predicted $R(D^0,P)$ for $P=\pi^0, \eta$ and $\eta'$ agree with experiment, the calculated $R(D^+,\pi^+)$, $R(D_s^+, K^+)$, $R(D^0,\omega)$ and $R(D^0,\phi)$ deviate from the data. We conjecture that the relative phase between the topological amplitudes $(C+A)$ and $(T+C)$ should be slightly smaller than $90^\circ$ in order to explain the first two discrepancies and that additional singlet contributions due to the SU(3)-singlet nature of $\omega$ and $\phi$ are needed to account for the last two. For doubly Cabibbo-suppressed (DCS) $D\to V\!P$ decays, their topological amplitudes (double-primed) cannot be all the same as the corresponding ones in the CF modes. The assumption of $E_{V,P}''=E_{V,P}$ for the $W$-exchange amplitude leads to some inconsistencies with the experiment. Through the measured relative phases between CF and DCS channels, the relations of $E_{V,P}''$ with $E_{V,P}$ are determined. Long-distance contributions to the $D^0$-$\overline {D}^0$ mixing parameter $y$ are evaluated in the exclusive approach. In particular, we focus on $D\to PP$ and $V\!P$ decays where $y$ can be reliably estimated. We conclude that $y_{_{P\!P}}\sim (0.110\pm 0.011)\%$ and the lower bound on $y_{_{V\!P}}$ is $(0.220\pm 0.071)\%$.

    Comment: 33 pages
    Keywords High Energy Physics - Phenomenology ; High Energy Physics - Experiment
    Subject code 612
    Publishing date 2024-01-11
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Online: Branching Fractions and CP Violation in $B^-\to K^+K^-\pi^-$ and $B^-\to \pi^+\pi^-\pi^-$ Decays

    Cheng, Hai-Yang / Chua, Chun-Khiang

    2020  

    Abstract: We present in this work a study of tree-dominated charmless three-body decays of $B$ mesons, $B^-\to K^+K^-\pi^-$ and $B^-\to\pi^+\pi^-\pi^-$, within the factorization approach. The main results are: (i) There are two distinct sources of nonresonant ... ...

    Abstract We present in this work a study of tree-dominated charmless three-body decays of $B$ mesons, $B^-\to K^+K^-\pi^-$ and $B^-\to\pi^+\pi^-\pi^-$, within the factorization approach. The main results are: (i) There are two distinct sources of nonresonant contributions: one arises from the $b\to u$ tree transition and the other from the nonresonant matrix element of scalar densities $\langle M_1M_2|\bar q_1 q_2|0\rangle^{\rm NR}$. It turns out that even for tree-dominated three-body decays, dominant nonresonant contributions originate from the penguin diagram rather than from the $b\to u$ tree process, as implied by the large nonresonant component observed recently in the $\pi^- K^+$ system which accounts for one third of the $B^-\to K^+K^-\pi^-$ rate. (ii) The calculated branching fraction of $B^-\to f_2(1270)\pi^-\to K^+K^-\pi^-$ is smaller than the LHCb by a factor of $\sim 7$ in its central value, but the predicted $\B(B^-\to f_2(1270)\pi^-\to\pi^+\pi^-\pi^-)$ is consistent with the data. Branching fractions of $B^-\to f_2(1270)\pi^-$ extracted from the LHCb measurements of these two processes also differ by a factor of seven! Therefore, it is likely that the $f_2(1270)$ contribution to $B^-\to K^+K^-\pi^-$ is largely overestimated experimentally. Including $1/m_b$ power corrections from penguin annihilation inferred from QCD factorization (QCDF), a sizable CP asymmetry of 32\% in the $f_2(1270)$ component agrees with experiment. (iii) A fraction of 5\% for the $\rho(1450)$ component in $B^-\to\pi^+\pi^-\pi^-$ is in accordance with the theoretical expectation. However, a large fraction of 30\% in $B^-\to K^+K^-\pi^-$ is entirely unexpected. This issue needs to be clarified in the future.

    Comment: 38 pages and 5 figures, references added and typos corrected
    Keywords High Energy Physics - Phenomenology ; High Energy Physics - Experiment
    Subject code 612
    Publishing date 2020-07-06
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: Revisiting CP violation in $D\to P\!P$ and $V\!P$ decays

    Cheng, Hai-Yang / Chiang, Cheng-Wei

    2019  

    Abstract: Direct CP violation in the hadronic charm decays provides a good testing ground for the Kobayashi-Maskawa mechanism in the Standard Model. Any significant deviations from the expectation would be indirect evidence of physics beyond the Standard Model. In ...

    Abstract Direct CP violation in the hadronic charm decays provides a good testing ground for the Kobayashi-Maskawa mechanism in the Standard Model. Any significant deviations from the expectation would be indirect evidence of physics beyond the Standard Model. In view of improved measurements from LHCb and BESIII experiments, we re-analyze the Cabibbo-favored $D \to P\!P$ and $V\!P$ decays in the topological diagram approach. By assuming certain SU(3)-breaking effects in the tree-type amplitudes, we make predictions for both branching fractions and CP asymmetries of the singly Cabibbo-suppressed decay modes. While the color-allowed and -suppressed amplitudes are preferred to scale by the factor dictated by factorization in the $P\!P$ modes, no such scaling is required in the $V\!P$ modes. The $W$-exchange amplitudes are found to change by 10\% to 50\% and depend on whether $d\overline{d}$ or $s\overline{s}$ pair directly emerges from $W$-exchange. The predictions of branching fractions are generally improved after these SU(3) symmetry breaking effects are taken into account. We show in detail how the tree-type, QCD-penguin, and weak penguin-annihilation diagrams contribute and modify CP asymmetry predictions. Future measurements of sufficiently many direct CP asymmetries will be very useful in removing a discrete ambiguity in the strong phases as well as discriminating among different theory approaches. In particular, we predict $a_{CP}(K^+K^-)-a_{CP}(\pi^+\pi^-) = (-1.14 \pm 0.26) \times 10^{-3}$ or $(-1.25 \pm 0.25) \times 10^{-3}$, consistent with the latest data, and $a_{CP}(K^+K^{*-})-a_{CP}(\pi^+\rho^-) = (-1.52 \pm 0.43) \times 10^{-3}$, an attractive and measurable observable in the near future. Moreover, we observe that such CP asymmetry differences are dominated by long-distance penguin-exchange through final-state rescattering.

    Comment: 31 pages. arXiv admin note: text overlap with arXiv:1205.0580
    Keywords High Energy Physics - Phenomenology ; High Energy Physics - Experiment
    Subject code 612
    Publishing date 2019-09-06
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article: Overexpressing NeuroD1 reprograms Müller cells into various types of retinal neurons.

    Xu, Di / Zhong, Li-Ting / Cheng, Hai-Yang / Wang, Zeng-Qiang / Chen, Xiong-Min / Feng, Ai-Ying / Chen, Wei-Yi / Chen, Gong / Xu, Ying

    Neural regeneration research

    2022  Volume 18, Issue 5, Page(s) 1124–1131

    Abstract: The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes ... ...

    Abstract The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes into neurons in vivo. Here, we demonstrate that in adult mice, NeuroD1 can reprogram Müller cells, the principal glial cell type in the retina, to become retinal neurons. Most strikingly, ectopic expression of NeuroD1 using two different viral vectors converted Müller cells into different cell types. Specifically, AAV7m8 GFAP681::GFP-ND1 converted Müller cells into inner retinal neurons, including amacrine cells and ganglion cells. In contrast, AAV9 GFAP104::ND1-GFP converted Müller cells into outer retinal neurons such as photoreceptors and horizontal cells, with higher conversion efficiency. Furthermore, we demonstrate that Müller cell conversion induced by AAV9 GFAP104::ND1-GFP displayed clear dose- and time-dependence. These results indicate that Müller cells in adult mice are highly plastic and can be reprogrammed into various subtypes of retinal neurons.
    Language English
    Publishing date 2022-10-18
    Publishing country India
    Document type Journal Article
    ZDB-ID 2388460-5
    ISSN 1876-7958 ; 1673-5374
    ISSN (online) 1876-7958
    ISSN 1673-5374
    DOI 10.4103/1673-5374.355818
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Leaky Mode Resonance-Induced Sensitive Ultraviolet Photodetector Composed of Graphene/Small Diameter Silicon Nanowire Array Heterojunctions.

    Wang, Jun-Jie / Fu, Can / Cheng, Hai-Yang / Tong, Xiao-Wei / Zhang, Zhi-Xiang / Wu, Di / Chen, Li-Miao / Liang, Feng-Xia / Luo, Lin-Bao

    ACS nano

    2021  Volume 15, Issue 10, Page(s) 16729–16737

    Abstract: Ultraviolet photodetectors (UVPDs) based on wide band gap semiconductors (WBSs) are important for various civil and military applications. However, the relatively harsh preparation conditions and the high cost are unfavorable for commercialization. In ... ...

    Abstract Ultraviolet photodetectors (UVPDs) based on wide band gap semiconductors (WBSs) are important for various civil and military applications. However, the relatively harsh preparation conditions and the high cost are unfavorable for commercialization. In this work, we proposed a non-WBS UVPD by using a silicon nanowire (SiNW) array with a diameter of 45 nm as building blocks. Device analysis revealed that the small diameter SiNW array covered with monolayer graphene was sensitive to UV light but insensitive to both visible and infrared light illumination, with a typical rejection ratio of 25. Specifically, the responsivity, specific detectivity, and external quantum efficiency under 365 nm illumination were estimated to be 0.151 A/W, 1.37 × 10
    Language English
    Publishing date 2021-10-04
    Publishing country United States
    Document type Journal Article
    ISSN 1936-086X
    ISSN (online) 1936-086X
    DOI 10.1021/acsnano.1c06705
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Direct Synthesis of Polyurea Thermoplastics from CO

    Jiang, Shan / Cheng, Hai-Yang / Shi, Ru-Hui / Wu, Pei-Xuan / Lin, Wei-Wei / Zhang, Chao / Arai, Masahiko / Zhao, Feng-Yu

    ACS applied materials & interfaces

    2019  Volume 11, Issue 50, Page(s) 47413–47421

    Abstract: The transformation of ... ...

    Abstract The transformation of CO
    Language English
    Publishing date 2019-12-09
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.9b17677
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Direct Synthesis of Polyurea Thermoplastics from CO2 and Diamines

    Jiang, Shan / Cheng, Hai-Yang / Shi, Ru-Hui / Wu, Pei-Xuan / Lin, Wei-Wei / Zhang, Chao / Arai, Masahiko / Zhao, Feng-Yu

    ACS applied materials & interfaces. 2019 Nov. 26, v. 11, no. 50

    2019  

    Abstract: The transformation of CO2 into polymeric materials is an important and hot research topic from the viewpoint of renewable resources and environmental effects. Herein, a series of polyureas have been synthesized by polycondensation from CO2 with diamines ... ...

    Abstract The transformation of CO2 into polymeric materials is an important and hot research topic from the viewpoint of renewable resources and environmental effects. Herein, a series of polyureas have been synthesized by polycondensation from CO2 with diamines of 1,12-diaminododecane (DAD) and/or 4,7,10-trioxa-1,13-tridecanediamine (TTD). The properties of polyureas synthesized were characterized by FTIR, 1H NMR, 13C NMR, XRD, DSC, TGA, and DMA. The polyureas synthesized from CO2 with a mixture of diamines presented high performances compared to those of polyureas synthesized from CO2 with a single diamine. The thermal and mechanical properties were improved largely by the variation in the crystallization and the chain flexibility depending on the changes in the density and/or intensity of hydrogen bonds. With increasing amounts of TTD from 0 to 100% in weight, the melting (Tm), crystallization (Tc), and glass transition (Tg) temperatures decreased from 207 to 116 °C, from 181 to 54 °C, and from 66 to −34 °C, respectively. When the TTD content was increased from 0 to 50 wt %, the Young’s modulus decreased from 1170 to 406 MPa, and the tensile strength decreased from 53.3 to 42.9 MPa. However, the elongation at break increased from 13 to 330%. Furthermore, the chain length of aliphatic diamines and polyetheramines had a significant effect on the mechanical properties. The initial decomposition temperature (Td,5%) is >295 °C, about 110 °C higher than the Tm (116–207 °C), which is advantageous for the postprocessing. The mechanical properties of the polyureas synthesized herein are superior to those of polycarbonate and polyamide 6. Thus, polyureas synthesized from the renewable and cheap resources, CO2 and diamines, will find wide potential applications in the field of polymeric materials.
    Keywords Fourier transform infrared spectroscopy ; X-ray diffraction ; carbon ; carbon dioxide ; condensation reactions ; crystallization ; diamines ; differential scanning calorimetry ; environmental impact ; glass transition ; hydrogen bonding ; melting ; modulus of elasticity ; nuclear magnetic resonance spectroscopy ; polyamides ; renewable resources ; stable isotopes ; temperature ; tensile strength ; thermogravimetry ; thermoplastics
    Language English
    Dates of publication 2019-1126
    Size p. 47413-47421.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1944-8252
    DOI 10.1021/acsami.9b17677
    Database NAL-Catalogue (AGRICOLA)

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  8. Book ; Conference proceedings: Proceedings of the Fourth International Workshop Particle Physics Phenomenology

    Cheng, Hai-Yang

    held at National Sun Yat-Sen University, June 18 - 21, 1998

    1999  

    Title variant Particle physics phenomenology
    Institution International Workshop Particle Physics Phenomenology
    Event/congress International Workshop "Particle Physics Phenomenology" (4, 1998.06.18-21, Kaohsiung)
    Author's details ed. Hai-Yang Cheng
    Language English
    Size IX, 356 S, graph. Darst
    Publisher World Scientific
    Publishing place Singapore u.a.
    Document type Book ; Conference proceedings
    ISBN 9810238177 ; 9789810238179
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  9. Book ; Online: On Charmless $B\to K_h\eta^{(')}$ Decays with $K_h=K,K^*,K_0^*(1430),K_2^*(1430)$

    Cheng, Hai-Yang / Chua, Chun-Khiang

    2010  

    Abstract: We study the charmless decays $B\to K_h\eta$ and $B\to K_h\eta'$ within the framework of QCD factorization (QCDF) for $K_h= K,K^*,K_0^*(1430)$ and naive factorization for $K_h=K_2^*(1430)$. There are three distinct types of penguin contributions: (i) $b\ ... ...

    Abstract We study the charmless decays $B\to K_h\eta$ and $B\to K_h\eta'$ within the framework of QCD factorization (QCDF) for $K_h= K,K^*,K_0^*(1430)$ and naive factorization for $K_h=K_2^*(1430)$. There are three distinct types of penguin contributions: (i) $b\to sq\bar q\to s\eta_{q}$, (ii) $b\to ss\bar s\to s\eta_s$, and (iii) $b\to s q\bar q\to q \bar K_h$, where $\eta_q=(u\bar u+d\bar d)/\sqrt{2}$ and $\eta_s=s\bar s$. $B\to K^{(*)}\eta^{(')}$ decays are dominated by type-II and type-III penguin contributions. The interference, constructive for $K\eta'$ and $K^*\eta$ and destructive for $K\eta$ and $K^*\eta'$, between type-II and type-III diagrams explains the pattern of $\Gamma(B\to K\eta')\gg\Gamma(B\to K\eta)$ and $\Gamma(B\to K^*\eta')\ll\Gamma(B\to K^*\eta)$. Within QCDF, the observed large rate of the $K\eta'$ mode can be naturally explained without invoking flavor-singlet contributions or something exotic. The decay pattern for $B\to K_0^*(1430)\eta^{(')}$ decays depends on whether the scalar meson $K_0^*(1430)$ is an excited state of $\kappa$ or a lowest-lying $P$-wave $q\bar q$ state. Hence, the experimental measurements of $B\to K_0^*(1430)\eta^{(')}$ can be used to explore the quark structure of $K_0^*(1430)$. If $K_0^*(1430)$ is a low-lying $q\bar q$ bound state, we find that $K_0^*\eta$ has a rate slightly larger than $K_0^*\eta'$ owing to the fact that the $\eta$-$\eta'$ mixing angle in the $\eta_q,\eta_s$ flavor basis is less than $45^\circ$, in agreement with experiment. Type-III penguin diagram does not contribute to $B\to K_2^*\eta^{(')}$ under the factorization hypothesis and type-II diagram dominates.

    Comment: 18 pages, 1 figure
    Keywords High Energy Physics - Phenomenology
    Subject code 551
    Publishing date 2010-05-11
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Connected-sea partons.

    Liu, Keh-Fei / Chang, Wen-Chen / Cheng, Hai-Yang / Peng, Jen-Chieh

    Physical review letters

    2012  Volume 109, Issue 25, Page(s) 252002

    Abstract: According to the path-integral formalism of the hadronic tensor, the nucleon sea contains two distinct components called the connected sea (CS) and the disconnected sea (DS). We discuss how the CS and DS are accessed in the lattice QCD calculation of the ...

    Abstract According to the path-integral formalism of the hadronic tensor, the nucleon sea contains two distinct components called the connected sea (CS) and the disconnected sea (DS). We discuss how the CS and DS are accessed in the lattice QCD calculation of the moments of the parton distributions. We show that the CS and DS components of ū(x) + d(x) can be extracted by using recent data on the strangeness parton distribution, the CT10 global fit, and the lattice result of the ratio of the strange to u(d) moments in the disconnected insertion. The extracted CS and DS for ū(x) + d(x) have a distinct Bjorken x dependence in qualitative agreement with expectation. The analysis also shows that the momentum fraction of ū(x) + d(x) is about equally divided between the CS and DS at Q(2) = 2.5 GeV(2). Implications for the future global analysis of parton distributions are presented.
    Language English
    Publishing date 2012-12-21
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.109.252002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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