Electron-proton elastic-scattering cross sections have been measured at the Stanford Linear Accelerator Center for four-momentum transfers squared q 2 from 1.0 to 25.0 (GeVc)2. The electric (GEp) and magnetic (GMp) form factors of the proton were not separated, since angular distributions were not measured at each q 2. However, values for GMp were derived assuming various relations between GEp and GMp. Several theoretical models for the behavior of the proton magnetic form factor at high values of q 2 are compared with the data.
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Based on a sample of 22 four-prong D 0 / D 0 decays produced in hydrogen by 360 GeV/ c π − , we present the following new results: mean lifetime τ = (3.5 −0.9 +1.4 ) x 10 −13 s ; production cross section for x F > 0.0, σ = (10.3 ± 3.5) ωb ; the D → K ± π ± π + π − branching ratio = (7.1 ± 2.5)%.
Measurements of the double differential cross sections for ππ and pπ production in pp collisions at the CERN ISR are presented for 5 c.m. energies s = 22, 30, 44, 53, 62 GeV . Charge and transverse momentum correlations are also reported.
Results are given on the inclusive production of charged pions, kaons, and nucleons, in proton-proton collisions at c.m. energies from √ s = 23 to 63 GeV at large angles and for the transverse momentum range 0.1 < p T < 4.8 GeV/ c . The dependence of the production spectra on the collision energy √ s , the transverse momentum p T , and the longitudinal rapidity is discussed.
Axis error includes +- 6.0/6.0 contribution (NORMALIZAION ERROR - THE LARGEST SYSTEMATICS).
Sixty-two charm events have been observed in an exposure of the SLAC Hybrid Facility toa backward sacttered laser beam. Based on 22 neutral and 21 charged decays we have measured the charmed-meson lifetimes to be τD0=(6.8−1.8+2.3)×10−13 sec, τD±=(7.4−2.0+2.3)×10−13 sec and their ratio τD±τD0=1.1−0.3+0.6. The inclusive charm cross section at a photon energy of 20 GeV has been measured to be 56−23+24 nb. Evidence is presented for a non-DD¯ component to charm production, consistent with (35±20)% Λc+ production and some D*± production. We have found no unambiguous F decays.
The π0 inclusive cross section for c.m. production angles θ=90° and 22°>~θ>~5° at c.m. energies of s=23 and 53 GeV has been measured. This cross section is strongly dependent on both θ and s at small angles. The hypothesis of radial scaling is shown to be incapable of incorporating both θ and s dependence of the cross section. A recent quantum-chromodynamics calculation is in qualitative agreement with our results.
Most events with high neutral transverse energy, E T 0 , produced in pp colisions at √ s = 62.3 GeV, are jet-like. The evidence for this is presented, based on data collected using an electromagnetic calorimeter covering 90% of 2π in azimuth. The spectrum d N /d E T 0 has been measured over the E T 0 range from 10 to 35 GeV. Properties of the observed jets are discussed.
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A measurement of the nucleon structure function F 2 on iron is presented. The data cover a kinematic range of 3.25 ⪕ Q 2 ⪕ 200 GeV 2 and 0.05 ⪕ x ⪕ 0.65 . The data clearly show scaling violation. Fits in leading-order QCD have been made and values for the scale breaking parameter λ are given.
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The proton structure function F 2 has been measured in the range 2.5 ⪕ Q 2 ⪕ 170 GeV 2 and 0.03 ⪕ x ⪕ 0.65 . Scaling violation is clearly seen in the data. Results of fits to leading-order QCD are presented, together with values of the scale-breaking parameter λ.
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