The production of antideuterons has been observed in electron-positron annihilations at center-of-mass energies around 10 GeV. Antideuterons have been identified unambiguously by their energy loss in the drift chamber, their time-of-flight and the pattern of their energy deposition in the shower counters of the ARGUS detector. The production rate in the momentum range (0.6−1.8) GeV/ c is (1.6 −0.7 +1.0 ) × 10 −5 per hadronic event.
Results from 6 antideuterons detected (3 from UPSI(2S), 2 from (IS) and 1 from (4S)).
No description provided.
A search has been made for particles with charge Q = 1 3 , Q = 2 3 and Q = 4 3 produced in e + e − annihilation using the ARGUS detector at the e + e − storage ring DORIS, operating at a centre of mass energy around 10 GeV. No candidate events were found in 84.5 pb −1 of collected data. Upper limits are established for the cross section for the production of fractionally charged particles with masses up to 4 GeV c 2 , improving on previously obtained limits.
Two different models (I and II) are considered (see text).
The differential cross section and analyzing power of the reaction pp → d π + were measured for nine incident proton energies between 725 and 1000 MeV. A magnetic spectrometer was used to detect either deuterons or pions. Cross-section and analyzing-power angular distributions were respectively fitted with Legendre polynomial and associated Legendre function expansions, the coefficients of which were found to vary smoothly with energy in the vicinity of the alleged 3 F 3 dibaryon resonance.
Data present here in form of Legendre polynomial fit.
Legendre Polynomial fit to cross section.
Legendre polynomial fit to analysing power.
Using the ARGUS detector at DORIS, we have observed the production of F ± mesons in e + e − annihilation at a centre of mass energy of 10 GeV through their subsequent decays into φπ ± and φπ + π − π ± . The values obtained for [ R (e + e − →FX). Branching Ratio] are (1.47 ± 0.32 ± 0.20)% and (1.63 ± 0.42 ± 0.41)% respectively. The observed mass is (1973.6 ± 2.6 ± 3.0) MeV c 2 . The F momentum spectrum is as expected for the fragmentation of c quarks into charmed mesons, but is somewhat softer than for fragmentation into D ∗ mesons. The relevant angular distributions are consistent with a spin-zero assignment of the F meson.
RESULTS OF FITS FOR SPECIFIED DECAY CHANNELS.
ACCEPTANCE CORRECTED FRAGMENTATION FUNCTION FOR THE TWO DECAY CHANNELS COMBINED. X IS PF/PMAX. DATA HAVE BEEN READ FROM THE GRAPH.
Using the ARGUS detector at DORIS we have observed the prediction of the charged D ∗ meson in e + e − annihilation at a center of mass energy of 10 GeV. The D ∗ fragmentation function has been measured using the decay channels D ∗+ → D 0 π + and D 0 → K − π + and K − π + π + π − .
RESULTS EXTRAPOLATED TO X>O. SYSTEMATIC ERRORS INCLUDED.
ERRORS ARE STATISTICAL ONLY.
Using the ARGUS detector at DORIS we have obtained evidence for a resonance which decays into an F meson and a photon. The observed mass is 2109 ± 9 ± 7 MeV, which is 144 ± 9 ± 7 MeV greater than the F meson mass. Its properties are consistent with those of the F ∗ meson with J P = 1 − .
No description provided.
The differential cross sections for lepton pair production in e+e− annihilation at 29 GeV have been measured and found to be in good agreement with the standard model of the electroweak interaction. With the assumption of e−μ−τ universality, the weak neutral-current couplings are determined to be ga2=0.23±0.05 and gv2=0.03±0.04.
Numerical values supplied by M.Levi.
Data requested from authors.
Extrapolated to full angular range.
A search has been made for the inclusive production of J ψ (3.1) and ϒ (9.4) mesons in e + e − interactions at 29 GeV, via their decay into two leptons. No signal is observed in the J ψ region, nor in the ϒ region. The limits on the cross sections are σ ( e + e − → ψX ) < 4.4 × 10 −36 cm 2 , and σ ( e + e − → ϒX ) < 4.7 × 10 −36 cm 2 . The same data yield limits on the branching ratios for the b quark BR ( b → ψX ) < 4.9% and BR ( b → ℓ + ℓ − X ) < 0.8%.
No description provided.
No description provided.
The total momentum and transverse momentum spectra of electrons in e+e− annihilation at 29 GeV have been measured. The inclusive cross section is determined to be 14.4±1.6±5.2 pb for momenta greater than 2 GeV/c. The average semielectronic branching ratios of charm and bottom quarks are measured to be (6.3±1.2±2.1)% and (11.6±2.1±1.7)%, respectively. The fragmentation function for bottom quarks is determined to be peaked at high z, with 〈z〉b=0.75±0.05±0.04.
PT is the transverse momentum of the muon relative to the event thrust axis.
PT is the transverse momentum of the muon relative to the event thrust axis.
Measurements are presented of the inclusive charged-particle cross sections s dσdx for e+e− annihilation at center-of-mass energies of 5.2, 6.5, and 29.0 GeV. Significant scale breaking is observed in these cross sections.
CROSS SECTION S*D(SIG)/DX FOR CHARGED PARTICLES AT SQRT(S) = 5.2, 6.5 AND 29.0 GEV. NUMERICAL VALUES OF DATA TAKEN FROM THESIS OF J.F. PATRICK LBL-14585.
Forum