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排序方式: 共有534条查询结果,搜索用时 78 毫秒
61.
Gavin J. Davies 《Frontiers of Physics》2013,8(3):270-284
This article reviews the Higgs searches at the Tevatron, as presented over the summer of 2012; both standard model (SM) and beyond the standard model (BSM) results are discussed as detailed (arXiv: 1207.0449; Phys. Rev. Lett., 2012, 109: 071804; Phys. Rev. D, 2012, 85: 032005). We discuss the combination of searches by the CDF and D0 Collaborations for the standard model Higgs boson in the mass range 100–200 GeV/c 2 produced in the the gg → H, WH, ZH, t{ie27-1}H, and vector boson fusion production modes, and decaying in the H → b{ie27-2}, H → W + W ?, H → ZZ, H → τ + τ ?, and H → γγ modes. The data, collected at the Fermilab Tevatron collider in p{ie27-3} collisions at {ie27-4} TeV, correspond to integrated luminosities of up to 10 fb?1. In the absence of signal, we expect to exclude the regions 100<m H < 120 GeV/c 2 and 139<m H < 184 GeV/c 2. We exclude, at the 95% C.L., two regions: 100<m H < 103 GeV/c 2, and 147<m H < 180 GeV/c 2. We observe a significant excess of events in the mass range between 115 and 140 GeV/c 2. The local significance corresponds to 3.0 standard deviations at m H = 120 GeV/c 2; the global significance (incorporating the look-elsewhere effect) for such an excess anywhere in the full mass range investigated is approximately 2.5 standard deviations. Furthermore, we separately combine searches for H → b{ie27-5}, H → W+W ? and H → γγ. We find that the excess is concentrated in the H → b{ie27-6} channel, appearing in the searches over a broad range of m H ; the maximum local significance of 3.3 standard deviations corresponds to a global significance of approximately 3.1 standard deviations. The observed signal strengths in all channels are consistent with the expectation for a standard model Higgs boson at m H = 125 GeV/c 2. The production of neutral Higgs bosons in association with b-quarks can be significantly enhanced in various beyond the standard model scenarios, including Supersymmetry. The recent combination of such searches from the two collaborations is discussed. 相似文献
62.
Sean Gavin 《Acta Physica Hungarica A》2005,24(1-4):65-70
63.
A mild and improved method for the synthesis of thioethers has been developed. In the presence of cesium carbonate, tetrabutylammonium iodide, and DMF, various alkyl and aryl thiols underwent S-alkylation to afford structurally diverse sulfides in high yield. Unprotected mercaptoalcohols and thioamines reacted chemoselectively at the sulfur moiety exclusively. An example of a one-pot, solid-phase synthesis of a thioether is also described. 相似文献
64.
John H. Morris Gavin S. Peters Elena Koldaeva Raisa Spryshkova Gergy Borisov 《应用有机金属化学》1995,9(4):323-325
7-(CH3)3N-4-{2,4-(NO2)2C6H3S}-nido-7-CB10H11 has been synthesized through a Friedel-Crafts substitution reaction on 7-(CH3)3N-nido-7- CB10H12. A biodistribution study in mice with implanted B16 melanoma indicates that the compound locates in neoplastic tissue at concentrations which suggest that its use in 10B neutron capture therapy may be feasible. 相似文献
65.
The composition of different oakmoss extracts was investigated by combined gas chromatography/mass spectrometry. A series of 38 compounds – especially phenol derivatives and monoterpenes – was identified, 22 of which have not yet been reported as constituents of oakmoss. 相似文献
66.
67.
Gavin R. Caine Simon J. Dunne Ellak I. Von Nagy-Felsobuki 《Journal of heterocyclic chemistry》1995,32(1):89-96
The He I and He II ultraviolet photoelectron spectra of 2-fluoro-, 2-chloro-, 2-bromo-, and 2-iodopyridine have been recorded and interpreted in terms of a composite-molecule model. The sequence of the four lowest ionization energies for 2-fluoro- and 2-chloropyridine is: π3 (1a2) > nN (11a1) > π2 (2b1) > πpyr (7b2), whereas for 2-bromo- and 2-iodopyridine the assignment is: π3 (1a2) - πX > nN (11a1) > πX > π2 (2b1), where X represents a bromine and iodine lone-pair. Comparison of the He I and He II band intensities confirmed this assignment. However, ab initio calculations at the STO-3G*/STO-3G* and 6–31G**/STO-3G* levels did not agree with the sequence predicted by either the composite-molecule model, simple correlations and the He I/He II cross-section ratios. For the 2-fluoropyridine, a comparison using the HAM/3 model was found to be in agreement with this assignment. 相似文献
68.
Gavin E. Crooks 《Journal of statistical physics》1998,90(5-6):1481-1487
An equality has recently been shown relating the free energy difference between two equilibrium ensembles of a system and an ensemble average of the work required to switch between these two configurations. In the present paper it is shown that this result can be derived under the assumption that the system's dynamics is Markovian and microscopically reversible. 相似文献
69.
Albert Padwa Mitsuo Akiba Leslie A. Cohen J.Gavin MacDonald 《Tetrahedron letters》1981,22(26):2435-2438
Thermolysis and photolysis of several allyl substituted oxazolin-5-ones results in a sigmatropic rearrangement in accord with orbital symmetry predictions. 相似文献
70.
Travasso RD Buxton GA Kuksenok O Good K Balazs AC 《The Journal of chemical physics》2005,122(19):194906
Through a combination of simulation techniques, we determine both the structural evolution and mechanical properties of blends formed from immiscible ternary mixtures. In this approach, we first use the lattice Boltzmann method to simulate the phase separation dynamics of A/B/C fluid mixtures for varying compositions within the spinodal region. We also investigate the effect of an imposed shear on the phase ordering of the mixture. We assume that the fluid is quenched sufficiently rapidly that the phase-separated structure is preserved in the resultant solid. Then, the output from our morphological studies serves as the input to the lattice spring model, which is used to simulate the elastic response of solids to an applied deformation. These simulations reveal how the local stress and strain fields and the global Young's modulus depend on the composition of the blend and the stiffness of the components. By comparing the results for the sheared and unsheared cases, we can isolate optimal processing conditions for enhancing the mechanical performance of the blends. Overall, the findings provide fundamental insight into the relationship between structure, processing, and properties for heterogeneous materials and can yield guidelines for formulating blends with the desired macroscopic mechanical behavior. 相似文献