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排序方式: 共有695条查询结果,搜索用时 31 毫秒
641.
B.Golob for the Belle Collaboration Jozef Stefan Institute Faculty of Mathematics Physics Univ.of Ljubljana Ljubljana Slovenia 《中国物理 C》2008,(6)
We present a preliminary measurement of the B(D_s→μν_μ)with the Belle experiment at the KEKB collider.We select D~s→μV_μdecays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction.The results are based on a data sample of 550 fb~(-1)and are compared to similar measurements by other experiments as well as to the predictions of LQCD.We conclude with short prospects for improvements in the accuracy of the measurement. 相似文献
642.
J. L. Bailly A. Batunin B. Buschbeck C. Caso Y. Chiba H. Dibon F. J. Diez-Hedo T. Emura B. Epp A. Ferrando F. Fontanelli T. Gemesy P. Girtler I. V. Gorelov A. Gurtu R. Hamatsu Ph. Herquet T. Hirose J. Hrubec Y. Iga E. Kistenev T. Kobayashi J. M. Kohli S. Krasznovszky P. K. Malhotra J. C. Marin M. Markytan I. S. Mittra L. Mohtanet G. Neuhofer G. Pinter P. Porth T. Rodrigo J. B. Singh S. Squarcia K. Sudhakar L. A. Tikhonova U. Trevisan T. Tsurugai V. Yarba G. Zholobov EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,31(3):367-373
643.
Possibilities of NEMO technique for future neutrinoless double-beta-decay experiments are discussed. Main idea is to have a realistic project with planned sensitivity for half-life on the level (1-2) × 1026 y (sensitivity to neutrino mass (0.05-0.1) eV). It is demonstrated that this can be achieved using improved NEMO technique to investigate 100 kg of 82Se. Possible improvements of NEMO technique and background conditions are discussed. Scheme of future SUPERNEMO detector and main characteristics of experiment are presented. Such detector can be used also to investigate 0 decay in 100Mo, 130Te and 116Cd with sensitivity up to (5-10)×1025 y (or with sensitivity to neutrino mass 0.1 eV). 相似文献
644.
645.
利用在北京谱仪上获取的1.27×106ψ(2S)事例研究了末态为矢量介子与赝标量分子的ψ(2S)两体衰变过程,ψ(2S)→ρπ及KK,得到它们的衰变分支比上限在90%置信度下分别为3.6×10-5(ρπ),2.5×10-5(K+K-+C.C.)(C.C.代表电荷共轭态)及1.2×10-4(K0K0+C.C.).这些结果在新的实验灵敏度水平上证实了ψ(2S)相对于J/ψ强衰变中的反常压制现象的存在. 相似文献
646.
Agakichiev G Appelshäuser H Baur R Bielcikova J Braun-Munzinger P Cherlin A Drees A Esumi SI Filimonov K Fraenkel Z Fuchs Ch Glässel P Hering G Huovinen P Lenkeit B Marín A Messer F Messer M Milosevic J Miśkowiec D Nix O Panebrattsev Y Petrácek V Pfeiffer A Rak J Ravinovich I Razin S Rehak P Sako H Saveljic N Schmitz W Shimansky S Socol E Specht HJ Stachel J Tilsner H Tserruya I Voigt C Voloshin S Weber C Wessels JP Wurm JP Yurevich V;CERES Collaboration 《Physical review letters》2004,92(3):032301
Elliptic flow and two-particle azimuthal correlations of charged hadrons and high-p(T) pions (p(T)>1 GeV/c) have been measured close to midrapidity in 158A GeV/c Pb+Au collisions by the CERES experiment. Elliptic flow (v(2)) rises linearly with p(T) to a value of about 10% at 2 GeV/c. Beyond p(T) approximately 1.5 GeV/c, the slope decreases considerably, possibly indicating a saturation of v(2) at high p(T). Two-pion azimuthal anisotropies for p(T)>1.2 GeV/c exceed the elliptic flow values by about 60% in midcentral collisions. These nonflow contributions are attributed to nearside and back-to-back jetlike correlations, the latter exhibiting centrality dependent broadening. 相似文献
647.
Tau-pair production in the process
was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb-1. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.Received: 18 September 2003, Revised: 26 March 2004, Published online: 11 May 2004 相似文献
648.
Measurement of anti-deuteron photoproduction and a search for heavy stable charged particles at HERA
The H Collaboration 《The European Physical Journal C - Particles and Fields》2004,36(4):413-423
The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of
GeV in the range 0.2 < p
T
/M < 0.7 and |y| < 0.4, where M, p
T
and y are the mass, transverse momentum and rapidity of the anti-deuteron in the HERA laboratory frame, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B
2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be
, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.Received: 31 March 2004, Revised: 23 June 2004, Published online: 30 July 2004 相似文献
649.
A search for pair-produced sfermions, the scalar supersymmetric partners of the Standard Model fermions, under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about 610 pb-1 collected at centre-of-mass energies of
GeV. An important consequence of R-parity violation is that the lightest supersymmetric particle is expected to be unstable. Searches for R-parity violating decays of charged sleptons, sneutrinos and squarks have been performed under the assumptions that the lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield final states consisting of leptons, jets, or both, with or without missing energy. No significant signal-like excess of events has been observed with respect to the Standard Model expectations. Limits on the production cross-sections of sfermions in R-parity violating scenarios are obtained. Constraints on the supersymmetric particle masses are also presented in an R-parity violating framework analogous to the Constrained Minimal Supersymmetric Standard Model.Received: 25 June 2003, Published online: 13 February 2004 相似文献
650.
The spin-parity analysis of the data on the
annihilation reaction at rest in liquid and in gaseous hydrogen at 3 bar pressure and in flight at
momentum of
MeV/c, collected by the Obelix spectrometer at the LEAR complex of CERN, is presented. The relative branching ratios
and
are obtained. It is also shown that the inclusion of the exotic meson
, JPC = 1- + , mass and width
,
GeV/c2, in its decay to
, improves the fit and some implications of these results are briefly discussed. The relative S and P-wave annihilation percentages in four charged pions at two target densities are obtained.Received: 2 December 2003, Published online: 23 April 2004 相似文献