The ratio of the electron and muon widths of the J/ psi J/ psi meson has been measured using direct J/ psi J/ psi decays in the KEDR experiment at the VEPP-4M electron-positron collider. The result ...Gamma e+e-(J/ psi )/ Gamma mu + mu -(J/ psi )=1.0022 plus or minus 0.0044 plus or minus 0.0048(0.65%) is in good agreement with the lepton universality. The experience collected during this analysis will be used for J/ psi J/ psi lepton width determination with up to 1% accuracy.
Measurement of parameters Anashin, V V; Aulchenko, V M; Baldin, E M ...
Physics letters. B,
05/2012, Letnik:
711, Številka:
3-4
Journal Article
Recenzirano
We report the final results of a study of the psi ( 3770 ) meson using a data sample collected with the KEDR detector at the VEPP-4M electron-positron collider. The data analysis takes into account ...interference between the resonant and nonresonant D D macr production, where the latter is related to the nonresonant part of the energy-dependent form factor F D . The vector dominance approach and several empirical parameterizations have been tried for the nonresonant F D N R ( s ) . Our results for the mass and total width of psi ( 3770 ) are M = 3779.2 - 1.7 + 1.8 - 0.7 + 0.5 - 0.3 + 0.3 MeV , Gamma = 24.9 - 4.0 + 4.6 - 0.6 + 0.5 - 0.9 + 0.2 MeV , where the first, second and third uncertainties are statistical, systematic and model, respectively. For the electron partial width two possible solutions have been found: ( 1 ) Gamma e e = 154 - 58 + 79 - 9 + 17 - 25 + 13 eV , ( 2 ) Gamma e e = 414 - 80 + 72 - 26 + 24 - 10 + 90 eV . Our statistics are insufficient to prefer one solution to another. The Solution (2) mitigates the problem of non- D D macr decays but is disfavored by potential models. It is shown that taking into account the resonance-continuum interference in the near-threshold region affects resonance parameters, thus the results presented cannot be directly compared with the corresponding PDG values obtained ignoring this effect.
A high-precision determination of the main parameters of the psi ( 2 S ) resonance has been performed with the KEDR detector at the VEPP-4M e + e - collider in three scans of the psi ( 2 S ) - psi ( ...3770 ) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of the psi ( 2 S ) we obtained the mass value M = 3686.114 plus or minus 0.007 plus or minus 0.011 - 0.012 + 0.002 MeV and the product of the electron partial width by the branching fraction into hadrons Gamma e e B h = 2.233 plus or minus 0.015 plus or minus 0.037 plus or minus 0.020 keV . The first and second uncertainties are statistical and systematic, respectively. The third uncertainty quoted is an estimate of the model dependence of the result due to assumptions on the interference effects in the cross section of the single-photon e + e - annihilation to hadrons explicitly considered in this work. Implicitly, the same assumptions were employed to obtain the charmonium leptonic width and the absolute branching fractions in many experiments. Using the result presented and the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of the psi ( 2 S ) : Gamma e e = 2.282 plus or minus 0.015 plus or minus 0.038 plus or minus 0.021 keV , Gamma = 296 plus or minus 2 plus or minus 8 plus or minus 3 keV . These results are consistent with and more than two times more precise than any of the previous experiments.
We report results of a search for narrow resonances in e super(+e) super(-) annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e ...super(+e) super(-) collider. The upper limit on the leptonic width of a narrow resonance inline image has been obtained (at 90% C.L.).
Syn-ore centroid type deformations that produced unusual structural assemblages are identified in the Uryakh ore field. The regularities of the deformation process comparable to a mechanism of the ...centroid-type seismic focus are established. The results of studying fluid inclusions suggest that the pressure—temperature parameters of the system correspond to conditions typical of the seismic regime. A model of formation of structural assemblages in a centroid-type dynamic regime with the participation of fluids is proposed for the first time.
A study of the Cladocera (Crustacea: Branchiopoda) from the Korean Peninsula resulted in the checklist of Jeong et al. (2014). Several sampling campaigns conducted by our team since 2014, with the ...framework of the programs supported by the National Institute of Biological Resources (NIBR), have resulted in a considerable increase in the number of water bodies studied in South Korea. In this report, seven new records for the Korean Peninsula are provided: (1) Macrothrix vietnamensis Silva-Briano, Dieu and Dumont, 1999; (2) Disparalona chappuisi (Brehm, 1931); (3) Pleuroxus(Picripleuroxus) quasidenticulatus (Smirnov, 1996); (4) Acroperus africanus Neretina and Kotov, 2015; (5) Alona ossiani herricki Sinev, 2013; (6) Coronatella trachystriata (Chen, Zhang and Liu, 1994); (7) Leydigia louisi Jenkin, 1934. Most of these taxa belong to the southern thermophilic complex. In addition several populations of Pleuroxus (Picripleuroxus) denticulatus Birge, 1879 and Pseudochydorus globosus (Baird, 1843) were re-studied, and their presence in Korea is confirmed. Through increased collection efforts and the application of molecular methods we are confident that more new records of Korean fauna will be published in the near future.
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