: We have measured the spin-dependent structure function $g_1~p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}~2<Q~2<60\,\mbox{GeV}~2$. Its first moment, $\int_0~1 g_1~p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q~2=10\,\mbox{GeV}~2$. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within $10\%$ of the theoretical value.
Results on the virtual photon proton asymmetry.
Results on the spin structure function of the proton.
Data for g1 at fixed Q**2 = 10 GeV (assuming no Q**2 dependence of A1).
The ratio R of the cross section for e+e− annihilation into hadronic final states to the QED cross section for muon-pair production is measured to be 4.34±0.45±0.30 and 4.23±0.20±0.21 at c.m. energies of 50 and 52 GeV, respectively. From these values of R and an analysis of the event shapes we deduce a 95%-confidence-level upper limit for the production rate of new heavy charge +23e or −13e quarks to be 0.19 units of R.
No description provided.
We report measurements from the CLEO detector of the rate of Ξ and Λ production in e+e− interactions in the upsilon region. Hyperon production from the decay of the ϒ(1s) is compared with continuum e+e− data. The ratio of the production rates of Λ (and Λ―) to K0 (and K―0) on the ϒ(1s) is 0.21 ± 0.03, much larger than in the continuum, 0.07 ± 0.01. The ratios of the production rates of the Ξ and Λ are comparable, 0.10±0.02 [ϒ(1S)] and 0.07 ± 0.02 (continuum). We discuss some implications of the data for gluon and quark fragmentation models.
CONTINUUM IS ECM 10.38 TO 10.64 GEV.
No description provided.
We have studied muon-produced hadrons from a deuterium target. The structure functions and the charge ratios are reported for neutrons; the transverse momentum and azimuthal distributions are reported for deuterons. The structure function for the neutron is similar to that of the proton. The charge ratio of produced hadrons follows the expectation of a simple spin-½ quark model. Transverse-momentum results agree with those at lower energy and are similar to those from hadron-hadron interactions. No azimuthal anisotropy is seen.
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