None
No description provided.
No description provided.
None
No description provided.
We observe evidence for a secon narrow resonance in the reation e + e − → hadrons at √s around 10 GeV using the DASP detector at the DORIS storage ring. The mass of the resonance is (10.01 ± 0.02) GeV; its width is in agreement with the storage ring resolution of ≈ 9 MeV. From the integrated cross section, an electronic width of Λ ee = (0.35 ± 0.14) KeV is derived.
No description provided.
We have measured inclusive γ and π0 production in multiprong events produced by e+e− annihilation in the center-of-mass energy range 4.9 to 7.4 GeV. We find the π0 inclusive cross section to be consistent in shape and normalization with half the charged-π cross section between x=0.15 and 0.60, with an integrated inclusive cross-section ratio of σ(π0)|σ(π+)+σ(π−)|=0.47±0.10.
NUMERICAL VALUES OF DATA FROM THIS EXPERIMENT HAVE NOT BEEN KEPT (M. L. PERL, PRIV COMM, 3 MAY 1979).
We observe a narrow resonance in the reaction e + e − → hadrons using the DASP detector at the DORIS storage ring. The mass is found to be (9.46 ± 0.01) GeV and the observed width is compatible with the storage ring resolution of ±8 MeV. The energy-integrated cross section results in an electronic width Γ ee = (1.3 ± 0.4) keV.
VISIBLE HADRONIC TOTAL CROSS SECTION.
We have measured inclusive electron production in multiprong events produced by e+e− annihilation in the center-of-mass energy range 3.9-7.4 GeV. We find the electron momentum spectra are consistent with the electrons coming mainly from decays of charmed particles, with a smaller contribution from decays of the τ lepton. From our data we calculate the average branching ratio for charmed particles to decay into an electron plus additional particles to be (8.2±1.9)%.
No description provided.
An experiment using the PLUTO detector has observed the formation of a narrow, high mass, resonance in e + e − annihilations at the DORIS storage ring. The mass is determined to be 9.46±0.01 GeV which is consistent with that of the Upsilon. The gaussian width σ is observed as 8±1 MeV and is equal to the DORIS energy resolution. This suggests that the resonance is a bound state of a new heavy quark-antiquark pair. An electronic width Γ ee =1.3±0.4 keV was obtained. In standard theoretical models, this favors a quark charge assignment of 1 3 .
No description provided.
Annihilation of e + e − into final states with a single electron has been studied with the PLUTO detector at the DORIS storage ring at CMS energies from 3.6 to 5 GeV. In the sample of 4-prong events without any detected photon we observe 21 events which we assign to the reaction e + e − → τ + τ − → νν e + νϱ 0 π . We obtain a branching ratio for τ + → νϱ 0 π + of 0.050 ± 0.015 with an overall systematic uncertainty of 30%. The data are consistent with the ϱπ coming from an A 1 meson.
No description provided.
The inclusive production of antiprotons and Λ's in e+e− annihilation has been measured as a function of the c.m. energy in the range 3.7-7.6 GeV. We find that the baryon cross section has a behavior different from the total hadronic production. Our results show a rapid rise in the ratio σp¯σμμ between 4.4 and 5 GeV, consistent with what would be expected from charmed baryon production. Λ¯ production is 10-15% of p¯ production at all energies.
NOT INCLUDING SYSTEMATIC ERRORS.
From a study of D mesons produced in the decay ψ(3772)→DD¯, we have determined the masses of the D0 and D+ mesons to be 1863.3±0.9 MeV/c2 and 1868.3±0.9 MeV/c2, respectively. Under the assumption that the ψ(3772) has a definite isospin and decays only to DD¯, the D0 branching fractions to K−π+, K¯0π+π−, and K−π+π−π+ are (2.2±0.6)%, (4.0 ± 1.3)%, and (3.2±1.1)% and the D+ branching fractions to K¯0π+ and K−π+π+ are (1.5±0.6)% and (3.9±1.0)%.
AROUND PSI(3772)0 PEAK. UPPER BOUNDS EACH SIDE OF PEAK ARE TABULATED IN M. PICCOLO ET AL., PL 86B, 220 (1979).
Forum