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951.
952.
A general procedure for the syntheses of diarylmercurials is presented. Reactions proceeded in isopropanol in the presence of a base and arylboronic acid. With one exception, all reactions proceeded in good to excellent yields, and this procedure was applicable to a variety of aromatic and heteroaromatic boronic acids. Products were characterized by multinuclear NMR spectroscopy and microanalysis, and investigated by DFT calculations. The structure of di(4-pyridyl)mercury (6) was further authenticated by X-ray crystallography. Combined with previous work on the formation of arylgold(I) complexes via arylboronic acids, this procedure may be generally useful for the arylation of late transition metals. 相似文献
953.
954.
Briere RA Chen GP Ferguson T Tatishvili G Vogel H Adam NE Alexander JP Berkelman K Boisvert V Cassel DG Drell PS Duboscq JE Ecklund KM Ehrlich R Galik RS Gibbons L Gittelman B Gray SW Hartill DL Heltsley BK Hsu L Jones CD Kandaswamy J Kreinick DL Magerkurth A Mahlke-Krüger H Meyer TO Mistry NB Patterson JR Peterson D Pivarski J Richichi SJ Riley D Sadoff AJ Schwarthoff H Shepherd MR Thayer JG Urner D Wilksen T Warburton A Weinberger M Athar SB Avery P Breva-Newell L Potlia V Stoeck H Yelton J 《Physical review letters》2003,90(18):181802
From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively. 相似文献
955.
Mahmood AH Csorna SE Danko I McLean KW Márka S Xu Z Godang R Kinoshita K Lai IC Schrenk S Bonvicini G Cinabro D McGee S Perera LP Zhou GJ Lipeles E Pappas SP Schmidtler M Shapiro A Sun WM Weinstein AJ Würthwein F Jaffe DE Masek G Paar HP Potter EM Prell S Sharma V Asner DM Eppich A Hill TS Morrison RJ Nelson HN Briere RA Chen GP Behrens BH Ford WT Gritsan A Roy J Smith JG Alexander JP Baker R Bebek C Berger BE Berkelman K Blanc F Boisvert V Cassel DG Dickson M Drell PS Ecklund KM Ehrlich R 《Physical review letters》2001,86(11):2232-2236
The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties. 相似文献
956.
Brown HN Bunce G Carey RM Cushman P Danby GT Debevec PT Deile M Deng H Deninger W Dhawan SK Druzhinin VP Duong L Efstathiadis E Farley FJ Fedotovich GV Giron S Gray F Grigoriev D Grosse-Perdekamp M Grossmann A Hare MF Hertzog DW Hughes VW Iwasaki M Jungmann K Kawall D Kawamura M Khazin BI Kindem J Krienen F Kronkvist I Larsen R Lee YY Logashenko I McNabb R Meng W Mi J Miller JP Morse WM Nikas D Onderwater CJ Orlov Y Ozben CS Paley JM Polly C Pretz J Prigl R zu Putlitz G Redin SI Rind O 《Physical review letters》2001,86(11):2227-2231
A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x 10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value. 相似文献
957.
Csorna SE Danko I McLean KW Xu Z Godang R Bonvicini G Cinabro D Dubrovin M McGee S Zhou GJ Bornheim A Lipeles E Pappas SP Schmidtler M Shapiro A Sun WM Weinstein AJ Jaffe DE Masek G Paar HP Asner DM Eppich A Hill TS Morrison RJ Briere RA Chen GP Ferguson T Vogel H Gritsan A Alexander JP Baker R Bebek C Berger BE Berkelman K Blanc F Boisvert V Cassel DG Drell PS Duboscq JE Ecklund KM Ehrlich R Foland AD Gaidarev P Galik RS Gibbons L Gittelman B Gray SW Hartill DL Heltsley BK Hopman PI Hsu L 《Physical review letters》2001,86(19):4243-4246
Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593). 相似文献
958.
959.
S. F. Biagi M. Bourquin A. J. Britten R. M. Brown H. Burckhart A. A. Carter J. R. Carter Ch. Doré P. Extermann M. Gailloud C. N. P. Gee W. M. Gibson J. C. Gordon R. J. Gray P. IgoKemenes W. C. Louis T. Modis P. Muhlemann J. Perrier Ph. Rosselet B. J. Saunders P. Schirato H. W. Siebert V. J. Smith D. P. Stickland K. -P. Streit J. J. Thresher R. Weill 《Zeitschrift fur Physik C Particles and Fields》1983,17(2):113-119
TheΞ - p differential elastic cross section has been measured in the SPS hyperon beam at 102 and 135 GeV/c. In the range 0.01<0.42(GeV/c)2, thet distributions are found to be compatible with the formA exp(Bt) whereB is 7.7±0.4(GeV/c)?2 at 102 GeV/c and 8.2 ±0.5(GeV/c)?2 at 135 GeV/c. The corresponding total elastic cross sections areσ el=4.9±0.7 mb andσ el=5.6±0.9 mb, respectively. These results are compared with the predictions of phenomenological models. 相似文献
960.
Spectra at θlab = 8° have been measured for the 92, 94, 96, 98, 100Mo(6Li, 8B)90, 92, 94, 96, 98Zr and 90, 92, 94Zr(6Li, 8B)88, 90, 92Sr two-proton pickup reactions at 90 MeV. The strongest transitions to levels in the Zr isotopes are the 0+ → 0+ transitions to the g.s. and first excited 0+ states. The salient feature of the five Zr spectra is the large increase in 0+2 transition strength relative to that of the g.s. which is observed in the two heaviest isotopes, 96, 98Zr. In 90Zr, the 0+2 transition is weak whereas it is the dominant transition in 98Zr with twice the g.s. strength. These large variations in relative cross section, which are reproduced by DWBA calculations, are attributed to changing g.s. proton configurations in Zr. In the Sr spectra, which are distinctly different from the Zrspectra, the strongest transitions to excited states are to 2+ rather than 0+ states. The (6Li, 8B) reaction seems to be adequately described as a one-step cluster transfer of a T = 1, S = 0 proton pair. The suitability of this reaction for measurements of two-proton pickup is discussed. 相似文献