45 research outputs found

    Probing CP-violating htˉth\bar{t}t coupling in e+e−→hγe^{+}e^{-}\rightarrow h \gamma

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    We investigate the possibility of probing the CP-violating htˉth\bar{t}t coupling in the process e+e−→hÎłe^{+}e^{-}\rightarrow h \gamma at the future high luminosity e+e−e^{+}e^{-} colliders. Our numerical results show that the cross section for this process can be significantly increased for the allowed CP phase Ο\xi and center of mass energy. For example the cross section is about 6 times of that in the standard model (SM) for s=350 GeV\sqrt{s}=350~\mathrm{GeV} and Ο=3π/5\xi =3\pi/5 (see text for Ο\xi definition). The simulation for the signal process e+e−→hγ→bbˉγe^{+}e^{-}\rightarrow h \gamma \rightarrow b \bar{b}\gamma and its backgrounds shows that the signal significance can reach more than 4.8σ4.8\sigma and 2.3σ2.3\sigma for s=350 GeV, 500 GeV\sqrt{s}=350~\mathrm{GeV},\ 500~\mathrm{GeV} respectively, with the integrated luminosity L=3 ab−1\mathcal{L}=3~\text{ab}^{-1} and Ο∈[π/2,3π/5]\xi\in[\pi/2,3\pi/5]. For L=10 ab−1\mathcal{L}=10~\text{ab}^{-1}, the signal significance can be greater than 5 for s=350 GeV\sqrt{s}=350~\mathrm{GeV} and 3.9 for s=500 GeV\sqrt{s}=500~\mathrm{GeV} with the CP phase Ο∈[π/2,3π/5]\xi\in[\pi/2,3\pi/5]. Besides the cross section enhancement, the CP-violating htˉth\bar{t}t coupling will induce the forward-backward asymmetry AFBA_{FB} which is absent in the SM and is a clear signal of new CP violation. Compared with the AFBA_{FB} in the Higgs decay h→l+l−γh\rightarrow l^{+}l^{-}\gamma, the AFBA_{FB} can be greatly enhanced in the production process. For example AFBA_{FB} can reach 0.5 for cosâĄÎŸâ‰ƒ0.7\cos\xi\simeq 0.7 and s=500 GeV\sqrt{s}=500~\mathrm{GeV}. Due to the large backgrounds, the significance of the expected AFBA_{FB} can only be observed at 1.7σ1.7\sigma with L=10 ab−1\mathcal{L}=10~\text{ab}^{-1} and s=500 GeV\sqrt{s}=500~\mathrm{GeV}. It is essential to trigger the single photon in the final state to separate the bottom jets arising from scalar or vector bosons, in order to isolate the signal from the backgrounds more efficiently.Comment: Published version. 19 pages, 11 figures, 3 tables. Discussion on the forward-backward asymmetry is adde

    Yunia dichotoma, a lower devonian plant from Yunnan, China

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    This paper describes a new genus and species, Yunia dichotoma, collected from the Posonchong Formation of Siegenian age in the Wenshan district of Yunnan, China. The spiny axes are characterized by cruciate dichotomy. Associated, but not in organic connection, with the vegetative axes, are numerous elongate-elliptical or ovoid sporangia. One small branching system consisting of a single dichotomy bears the basal part of a sporangium, suggesting the possibility that the sporangia were borne terminally in pairs. Sections of permineralized segments of the axis reveal a columnar protostele, circular to elliptical in transverse section containing one or two roughly circular to transversely elongate (often lunate) regions of large parenchyma cells sparsely interspersed peripherally with tracheids of small diameter. We interpret these regions of parenchyma and tracheids to be protoxylem strands and development of primary xylem to be centrarch. During branching of an axis, the initially single protoxylem region in a branch stele divides precociously prior to the separation of the daughter axes. Thus, the stele may contain two protoxylem strands through considerable lengths of daughter axes between levels of dichotomy. Yunia is tentatively assigned to the Trimerophytales.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29227/1/0000282.pd

    Light anti-nuclei production in pp collisions at s\sqrt{s}=7 and 14 TeV

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    A dynamically constrained coalescence model based on the phase space quantization and classical limit method was proposed to investigate the production of light nuclei (anti-nuclei) in non-single diffractive (NSD) pp collisions at s\sqrt{s}=7 and 14 TeV. This calculation was based on the final hadronic state in the PYTHIA and PACIAE model simulations, the event sample consisted of 1.2×108\times 10^8 events in both simulations. The PACIAE model calculated Dˉ\bar D yield of 6.247×10−5\times 10^{-5} in NSD pp collisions at s\sqrt{s}=7 TeV is well comparing with the ALICE rough datum of 5.456×10−5\times 10^{-5}. It indicated the reliability of proposed method in some extent. The yield, transverse momentum distribution, and rapidity distribution of the Dˉ\bar D, 3Heˉ^3{\bar{He}}, and Λˉ3Hˉ_{\bar\Lambda} ^3{\bar H} in NSD pp collisions at s\sqrt{s} =7 and 14 TeV were predicted by PACIAE and PYTHIA model simulations. The yield resulted from PACIAE model simulations is larger than the one from PYTHIA model. This might reflect the role played by the parton and hadron rescatterings.Comment: 5 pages, 2 figure

    SPHENOTHALLUS FROM THE LOWER SILURIAN OF CHINA

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    Different physiological roles of insulin receptors in mediating nutrient metabolism in zebrafish

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    Insulin, the most potent anabolic hormone, is critical for somatic growth and metabolism in vertebrates. Type 2 diabetes, which is the primary cause of hyperglycemia. results from an inability of insulin to signal glycolysis and gluconeogenesis. Our previous study showed that double knockout of insulin receptor a (insra) and b (insrb) caused beta-cell hyperplasia and lethality from 5 to 16 days postfertilization (dpf) (Yang BY, Zhai G, Gong YL, Su JZ, Han D, Yin Z, Xie SQ. Sci Bull (Beijing) 62: 486-492, 2017). In this study, we characterized the physiological roles of Insra and Insrb. in somatic growth and fueling metabolism, respectively. A high-carbohydrate diet was provided for insulin receptor knockout zebrafish from 60 to 120 dpf to investigate phenotype inducement and amplification. We observed hyperglycemia in both insra-/- fish and insrb-/- fish. Impaired growth hormone signaling, increased visceral adiposity, and fatty liver were detected in insrb-/- fish, which are phenotypes similar to the lipodystrophy observed in mammals. More importantly, significantly diminished protein levels of P-PPAR alpha, P-STATS, and IGF-1 were also observed in insrb-/- fish. In insra-/- fish, we observed increased protein content and decreased lipid content of the whole body. Taken together, although Insra and Insrb show overlapping roles in mediating glucose metabolism through the insulin-signaling pathway, Insrb is more prone to promoting lipid catabolism and protein synthesis through activation of the growth hormone-signaling pathway, whereas Insra primarily acts to promote lipid synthesis via glucose utilization.</p

    Boosting Superior Lithium Storage Performance of Alloy‐Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid‐Electrolyte Interphase

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    Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g−1 after 200 cycles at 500 mA g−1, compared to only 72% and 170 mAh g−1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials

    The Large High Altitude Air Shower Observatory (LHAASO) Science White Paper

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    The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation multi-component instrument, to be built at 4410 meters of altitude in the Sichuan province of China, with the aim to study with unprecedented sensitivity the spec trum, the composition and the anisotropy of cosmic rays in the energy range between 1012^{12} and 1018^{18} eV, as well as to act simultaneously as a wide aperture (one stereoradiant), continuously-operated gamma ray telescope in the energy range between 1011^{11} and 101510^{15} eV. The experiment will be able of continuously surveying the TeV sky for steady and transient sources from 100 GeV to 1 PeV, t hus opening for the first time the 100-1000 TeV range to the direct observations of the high energy cosmic ray sources. In addition, the different observables (electronic, muonic and Cherenkov/fluorescence components) that will be measured in LHAASO will allow to investigate origin, acceleration and propagation of the radiation through a measurement of energy spec trum, elemental composition and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO in cosmic rays physics and gamma astronomy would play a key-role in the comprehensive general program to explore the High Energy Universe. LHAASO will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. In this document we introduce the concept of LHAASO and the main science goals, providing an overview of the project.Comment: This document is a collaborative effort, 185 pages, 110 figure

    Analysis of clinical features, serologic and cerebrospinal fluid tests in patients with neurosyphilis at different stages

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    Objective To summarize the clinical features, serologic, cerebrospinal fluid (CSF) tests in patients with neurosyphilis at different stages.  Methods A retrospective analysis was made on the clinical features, imaging, serologic and CSF tests, treatment and prognosis of 12 cases diagnosed as neurosyphilis. In those cases, 5 cases were early-stage neurosyphilis, including 4 syphilitic meningitis (meningomyelitis) and one meningovascular syphilis; 7 cases were late-stage neurosyphilis, all of whom were general paresis.  Results The serum Treponema pallidum antibody (TP-Ab) and rapid plasma regain (RPR) tests were positive in all 12 cases. The CSF TP-Ab tests of 12 cases were all positive and CSF RPR tests were positive in 9 cases. In 5 cases of early-stage neurosyphilis, one case had elevated intracranial pressure (ICP), 3 cases presented with elevated white blood cell (WBC), 4 cases had elevated protein concentration. In 7 cases of late-stage neurosyphilis, one case had elevated ICP, 7 cases presented with elevated WBC and protein concentration. CSF cytology showed lymphocyte reaction, mainly small lymphocytes. All cases were treated with different doses of intravenous penicillin or ceftriaxone sodium by intramuscular injection, among whom 8 cases presented improved neuropsychiatric symptoms, while 4 cases had no significant improvement.  Conclusions Neurosyphilis is easy to be misdiagnosed because of various styles of onset and nontypical clinical manifestations. A definite diagnosis depends on clinical manifestations and serologic and CSF examinations. Early diagnosis and standard treatment is essential for improving prognosis and reducing complications. DOI: 10.3969/j.issn.1672-6731.2016.07.005</p
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