This Letter presents measurements of the nucleon structure function F2(x,Q2) based on the deep-inelastic scattering of 215- and 93-GeV muons in the iron multimuon spectrometer at Fermilab. With use of a lowest-order QCD calculation, a value of ΛLO=230±40(stat.)±80(syst.) MeV/c is found.
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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.
We have studied the production of prompt muons in hadronic events from e+e− annihilation at a center-of-mass energy of 29 GeV with the PEP4-TPC (Time Projection Chamber) detector. The muon p and pt distributions are well described by a combination of bottom- and charm-quark decays, with fitted semimuonic branching fractions of (15.2±1.9±1.2)% and (6.9±1.1±1.1)%, respectively. The muon spectra imply hard fragmentation functions for both b and c quarks, with 〈z(b quark)〉=0.80±0.05±0.05 and 〈z(c quark)〉=0.60±0.06±0.04. We derive neutral-current axial-vector couplings of a(b quark)=-0.9±1.1±0.3 and a(c quark)=1.5±1.5±0.5 from the forward-backward asymmetries.
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. At this table MUON is from JET and its PT < 1 GeV/c.
PT is the transverse momentum of the MUON relative to the event thrust axis. At this table MUON is from JET and its PT > 1 GeV/c.
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Pt of the leptons is determined relative to the thrust axis. B-DECAY, C-DECAY, C-SECONDARY and BKG are corresponded to fractions of leptons originationg from primary BQ deacy, primary CQ decay, secondary decay, and from background.
Topological cross sections and characteristics of charged particle multiplicity distributions for¯nn andnn interactions and¯nn annihilations at 6·1 GeV/c are presented. KNO-distributions for¯nn andnn interactions are very similar. Characteristics for¯nn and¯pp annihilations are identical at equal energies.
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We have searched for the lepton-flavor-violating decay D0→e±μ∓ in 204 pb−1 of e+e− annihilation data at Ec.m.=29 GeV from the Mark II detector. No candidates were found; we estimate an upper limit on the cross section times branching ratio of σ(e+e−→D0,D¯0; inclusive)B(D0→e±μ∓)<0.35 pb at the 90% confidence level. Simple assumptions yield the rough limit B(D0→e±μ∓)<2.1×10−3. AE.
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We have searched for the annihilation of e+e− into the exclusive channels e±τ∓ and μ±τ∓ at √s =29 GeV, using 226 and 133 pb−1, respectively, of data taken with the Mark II detector at the SLAC storage ring PEP. The resulting candidate sample is compatible with the expected background from τ pair production. Our analysis yields 95%-C.L. cross-section limits of σeτ/σμμ<1.8×10−3 and σμτ/σμμ<6.1×10−3, where σμμ is the QED cross section for production of a lepton pair. This is the first high-Q2 test of lepton-flavor conservation involving τ leptons.
95 pct confidence upper limits.
The charge asymmetry of leptons from W-boson decay has been measured using p¯p data from the Collider Detector at Fermilab at √s =1.8 TeV. The observed asymmetry is well described by most of the available parton distributions.
Electrons in the central region.
Muons in the central region.
Plug electrons.
Forum