401 research outputs found

    The productions of the top-pions and top-Higgs associated with the charm quark at the hadron colliders

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    In the topcolor-assistant technicolor (TC2) model, the typical physical particles, top-pions and top-Higgs, are predicted and the existence of these particles could be regarded as the robust evidence of the model. These particles are accessible at the Tevatron and LHC, and furthermore the flavor-changing(FC) feature of the TC2 model can provide us a unique chance to probe them. In this paper, we study some interesting FC production processes of top-pions and top-Higgs at the Tevatron and LHC, i.e., cΞ tβˆ’c\Pi_{t}^{-} and cΞ t0(ht0)c\Pi_{t}^{0}(h_{t}^{0}) productions. We find that the light charged top-pions are not favorable by the Tevatron experiments and the Tevatron has a little capability to probe neutral top-pion and top-Higgs via these FC production processes. At the LHC, however, the cross section can reach the level of 10∼10010\sim 100 pb for cΞ tβˆ’c\Pi_t^- production and 10∼100 10\sim 100 fb for cΞ t0(ht0)c\Pi_t^0(h_t^0) production. So one can expect that enough signals could be produced at the LHC experiments. Furthermore, the SM background should be clean due to the FC feature of the processes and the FC decay modes Ξ tβˆ’β†’bcΛ‰,Ξ t0(ht0)β†’tcΛ‰\Pi_t^-\to b\bar{c}, \Pi_t^0(h_t^0)\to t\bar{c} can provide us the typical signal to detect the top-pions and top-Higgs. Therefore, it is hopeful to find the signal of top-pions and top-Higgs with the running of the LHC via these FC processes.Comment: 12 pages, 6 figure

    RevisiΓ³n sobre mΓ©todos de preparaciΓ³n, mecanismos y aplicaciones de pΓ©ptidos antioxidantes en aceites

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    Natural antioxidants, especially those used in edible oil, are safer compared to chemically synthesized antioxidants. Therefore, research on natural antioxidants has become prevelant. Antioxidant peptides derived from food protein can effectively prevent oil oxidation. Protein hydrolyzation is widely applied for the production of antioxidant peptides in industry, and bioinformatics is employed nowadays to generate the desired peptide sequence. Furthermore, the mechanism of antioxidant peptides in the oil system is still controversial, which limits the further development of antioxidant peptides as food antioxidants. This review introduces the preparation method of antioxidant peptides and their mechanisms as well as applications in the oil. It will help to comprehensively understand the function of antioxidant peptides and promote their development in the oil field.Los antioxidantes naturales, especialmente utilizados en aceites comestibles, son mΓ‘s seguros en comparaciΓ³n con los antioxidantes sintetizados quΓ­micamente. Por lo tanto, la investigaciΓ³n sobre antioxidantes naturales se convierte en un punto de interΓ©s. Los pΓ©ptidos antioxidantes derivados de las proteΓ­nas alimentarias pueden prevenir eficazmente la oxidaciΓ³n del aceite. La hidrolizaciΓ³n de proteΓ­nas se usa ampliamente en la industria para la producciΓ³n de pΓ©ptidos antioxidantes y la bioinformΓ‘tica se emplea hoy en dΓ­a para generar la secuencia de pΓ©ptidos deseada. AdemΓ‘s, el mecanismo de los pΓ©ptidos antioxidantes en el sistema oleoso sigue siendo controvertido, lo que limita el desarrollo posterior de pΓ©ptidos antioxidantes como antioxidantes alimentarios. Esta revisiΓ³n presenta el mΓ©todo de preparaciΓ³n de pΓ©ptidos antioxidantes y su mecanismo, asΓ­ como las aplicaciones en aceite, lo que ayudarΓ‘ a comprender de manera integral la funciΓ³n de los pΓ©ptidos antioxidantes y promoverΓ‘ su desarrollo en el campo petrolero

    Transgenic and Knockout Mice Models to Reveal the Functions of Tumor Suppressor Genes

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    Cancer is caused by multiple genetic alterations leading to uncontrolled cell proliferation through multiple pathways. Malignant cells arise from a variety of genetic factors, such as mutations in tumor suppressor genes (TSGs) that are involved in regulating the cell cycle, apoptosis, or cell differentiation, or maintenance of genomic integrity. Tumor suppressor mouse models are the most frequently used animal models in cancer research. The anti-tumorigenic functions of TSGs, and their role in development and differentiation, and inhibition of oncogenes are discussed. In this review, we summarize some of the important transgenic and knockout mouse models for TSGs, including Rb, p53, Ink4a/Arf, Brca1/2, and their related genes

    The improvement of Pd nanoclusters electro-catalytic properties for FAO by the addition of Co element

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    Conference Name:2014 International Conference on Materials Science and Engineering Technology, MSET 2014. Conference Address: Shanghai, China. Time:June 28, 2014 - June 29, 2014.East China University of Science and Technology; Engineering and Industry Technology Institute; Shanghai JiaoTong University; Shanghai University of Engineering ScienceNear-monodisperse Pd and PdCo nanoclusters were synthesized by physical vapor deposition using a plasma-gas-condensation cluster deposition system and tested for catalyzing formic acid oxidation. Under the condition of high vacuum and inert gas, NCs with clean surface and uniform size were obtained. The cyclic voltammetry tests revealed that the electrochemical surface area was increased from 49.7 m2 g-1 to 51.7 m2 g-1 and the peak current density of catalyzing FAO was raised from 0.115 mA cm-2 to 0.125 mA cm-2 when about 12wt. % Co element was added. Additionally, the tolerance to CO poisoning of Pd could also be improved by the addition of Co. The result indicated that this method offered a chemical-free way to prepare clean and efficient Pd-based nanoscale catalytics and encouraged deeper exploration for electrochemichal catalytic reactions. ? (2014) Trans Tech Publications, Switzerland

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8Γ—107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/Οˆβ†’Ξ³Ο•Ο•β†’Ξ³K+Kβˆ’KS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0βˆ’+0^{-+} state (Ξ·(2225)\eta(2225)) with a mass of 2.24βˆ’0.02+0.03βˆ’0.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19Β±0.03βˆ’0.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/Οˆβ†’Ξ³Ξ·(2225))β‹…Br(Ξ·(2225)→ϕϕ)=(4.4Β±0.4Β±0.8)Γ—10βˆ’4Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa

    Measurements of the observed cross sections for e+eβˆ’β†’e^+e^-\to exclusive light hadrons containing Ο€0Ο€0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

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    By analyzing the data sets of 17.3, 6.5 and 1.0 pbβˆ’1^{-1} taken, respectively, at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for e+eβˆ’β†’Ο€+Ο€βˆ’Ο€0Ο€0e^+e^-\to \pi^+\pi^-\pi^0\pi^0, K+Kβˆ’Ο€0Ο€0K^+K^-\pi^0\pi^0, 2(Ο€+Ο€βˆ’Ο€0)2(\pi^+\pi^-\pi^0), K+Kβˆ’Ο€+Ο€βˆ’Ο€0Ο€0K^+K^-\pi^+\pi^-\pi^0\pi^0 and 3(Ο€+Ο€βˆ’)Ο€0Ο€03(\pi^+\pi^-)\pi^0\pi^0 at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

    Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays

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    By analyzing about 33 pbβˆ’1\rm pb^{-1} data sample collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we directly measure the branching fractions for the neutral and charged DD inclusive semimuonic decays to be BF(D0β†’ΞΌ+X)=(6.8Β±1.5Β±0.7)BF(D^0 \to \mu^+ X) =(6.8\pm 1.5\pm 0.7)% and BF(D+β†’ΞΌ+X)=(17.6Β±2.7Β±1.8)BF(D^+ \to \mu^+ X) =(17.6 \pm 2.7 \pm 1.8)%, and determine the ratio of the two branching fractions to be BF(D+β†’ΞΌ+X)BF(D0β†’ΞΌ+X)=2.59Β±0.70Β±0.25\frac{BF(D^+ \to \mu^+ X)}{BF(D^0 \to \mu^+ X)}=2.59\pm 0.70 \pm 0.25

    A study of charged kappa in J/Οˆβ†’KΒ±KsΟ€βˆ“Ο€0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0

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    Based on 58Γ—10658 \times 10^6 J/ψJ/\psi events collected by BESII, the decay J/Οˆβ†’KΒ±KsΟ€βˆ“Ο€0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0 is studied. In the invariant mass spectrum recoiling against the charged Kβˆ—(892)Β±K^*(892)^{\pm}, the charged ΞΊ\kappa particle is found as a low mass enhancement. If a Breit-Wigner function of constant width is used to parameterize the kappa, its pole locates at (849Β±77βˆ’14+18)βˆ’i(256Β±40βˆ’22+46)(849 \pm 77 ^{+18}_{-14}) -i (256 \pm 40 ^{+46}_{-22}) MeV/c2c^2. Also in this channel, the decay J/Οˆβ†’Kβˆ—(892)+Kβˆ—(892)βˆ’J/\psi \to K^*(892)^+ K^*(892)^- is observed for the first time. Its branching ratio is (1.00Β±0.19βˆ’0.32+0.11)Γ—10βˆ’3(1.00 \pm 0.19 ^{+0.11}_{-0.32}) \times 10^{-3}.Comment: 14 pages, 4 figure

    Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV

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    By analyzing the data sets of 17.3 pbβˆ’1^{-1} taken at s=3.773\sqrt{s}=3.773 GeV and 6.5 pbβˆ’1^{-1} taken at s=3.650\sqrt{s}=3.650 GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 12 exclusive light hadron final states produced in e+eβˆ’e^+e^- annihilation at the two energy points. We have also set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay to these final states at 90% C.L.Comment: 8 pages, 5 figur
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