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.
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Final results of our measurements of elastic proton-proton scattering at the CERN Intersecting Storage Rings (ISR) for c.m. energies √ s from 23 to 63 GeV and momentum transfers | t | from 0.8 to 10 GeV 2 are presented. Absolute differential cross sections have been obtained using the split-field magnet detector facility (SFM) at the five standard energies for integrated luminosities ranging from 0.3 to 4.9 (pb) −1 . The rising total cross section is found to define a scale for diffractive phenomena near the forward peak, including the position of the diffraction minimum near t = −1.4 GeV 2 . The cross section at the minimum is strongly energy dependent, approximately as the ratio of the real to imaginary part of the scattering amplitude in the forward direction. The phase of the scattering amplitude is found to change sign near the minimum. The component of diffraction scattering beyond the second maximum has a much weaker t -dependence than expected in simple eikonal or constituent pictures connecting this region to the forward peak. A further break in slope is observed near t = −6 GeV 2 . There is no evidence for another minimum for t values up to 10 GeV 2 .
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We present results on the inclusive distributions of final-state hadrons created in deep-inelastic electron scattering from protons and deuterons. Data were taken from all portions of the kinematic range simultaneously in an apparatus which had equal detection efficiency for both charge signs. A subset of the produced hadrons were identified with a threshold-type Čerenkov counter. We find that the charge ratio h+h− is a strong function of Q2, xF, and pT2, with little dependence on s. The ratio of production of h− from deuterium to that from hydrogen as a function of φ is flat. The invariant cross section for each charge sign and each target exhibits the seagull effect (a correlation in 〈pT〉 and 〈xF〉). The value of 〈pT〉 for data in the range 0.4
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The backward production of the B(1235) meson is studied in the reaction K − p → Σ − π + ω . This reaction is observed in the final state Σ − π + π + π − π 0 . A π + ω mass enhancement is visible in the region of the B meson for events with small | u |K − → Σ − ) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K − p → Σ − B + at 4.15 GeV c incident K − momentum is (3.2 ± 0.5) μb . The backward production of the B meson is compared with similar baryon exchange productions of the A 1 and C(Q 1 ) axial vector mesons observed in the same experiment.
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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).
Measurements of the invariant cross section Ed3σd3p are presented for the production of hadrons (π, K, p, and p¯) at large transverse momentum (p⊥) by 200-, 300-, and 400-GeV protons incident on H2, D2, Be, Ti, and W targets. The measurements were made at a laboratory angle of 77 mrad, which corresponds to angles near 90° in the c.m. system of the incident proton and a single nucleon at rest. The range in p⊥ for the data is 0.77≤p⊥≤6.91 GeV/c, corresponding to values of the scaling variable x⊥=2p⊥s from 0.06 to 0.64. For p−p collisions, the pion cross sections can be represented in the region x⊥>35 by the form (1p⊥n)(1−x⊥)b, with n=8 and b=9. The ratio of π+ to π− production grows as a function of x⊥ to a value larger than 2 at x⊥≳0.5. The ratios of the production of K+ and protons to π+ and of K− and antiprotons to π− also scale with x⊥ for p−p collisions. The K±, p, and p¯ fitted values for n and b are given. Particle ratios are also presented for D2, Be, Ti, and W targets and the dependences on atomic weight (A) are discussed.
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We present measurements from a counter-optical spark chamber experiment of the differential cross sections for p̄p → π 0 π 0 , π 0 η 0 at 25 momenta in the range 1.1 − 2.0 GeV/ c (c.m. energy 2.12 to 2.43 GeV). Approximately 750 000 pictures were taken in the experiment.
THE ANGULAR DISTRIBUTIONS IN THE PUBLISHED FIGURES ARE NOT TABULATED HERE SINCE THEY ARE ONLY RECONSTRUCTED FROM THE LEGENDRE EXPANSION COEFFICIENTS WHICH WERE MEASURED DIRECTLY FROM THE DATA.
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LEGENDRE COEFFICIENTS NORMALIZED SO THAT LEG(L=0) = SIG/(2*PI) (IDENTICAL PARTICLES IN FINAL STATE). THESE ARE PLOTTED IN FIG. 1 OF THE FOLLOWING PAPER.
We present a partial wave amplitude analysis of the differential cross sections for p̄p → π 0 π 0 at 25 energies from 2.12 to 2.43 GeV. The results suggest the presence of a J PC I G = 2 ++ 0 + resonance at 2.15 GeV. An isospin decomposition of p̄p → π + π - is also presented.
THESE LEGENDRE COEFFICIENTS ARE TABULATED IN THE RECORD OF THE PRECEDING PAPER, R. S. DULUDE ET AL., PL 79B, 329 (1978).
We present results for the differential cross sections of neutrinos and antineutrinos on nucleons in the energy range E = 2−200 GeV, from the BEBC and Gargamelle experiments. The structure functions F 2 , 2 χF 1 and χF 3 have been evaluated as a function of χ and q 2 . Deviations are observed from Bjorken scaling, which are very similar to those found in electron and muon inelastic scattering. For the Callan-Gross ratio, we find 2χF 1 F 2 = 0.80 ± 0.12 and the corresponding value for 〈R〉 = 〈 σ S σ T 〉 = 0.15 ± 0.10 . Our results are consistent with the Gross-Llewellyn-Smith sum rule; we measure ⩾2.5 ± 0.5 valence quarks per nucleon. Quark and antiquark distributions are given. The Nachtmann moments of F 2 and χF 3 are quantitatively consistent with the predictions from QCD. The value of the strong interaction parameter is λ = 0.74 ± 0.05 GeV without corrections, and 0.66 ± 0.05 GeV including α S 2 corrections. The moments of the gluon distribution are found to be positive and indicate an χ distribution of gluons which is comparable with that of the valence quarks.
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The reaction K − n → K − π + π − n has been studied in the SLAC 82″ liquid deuterium bubble chamber with a beam momentum of 12 GeV/ c . Although the kinematic fit for this final state has only one constraint, nonetheless a reasonably pure sample has been obtained. The cross section for the reaction is 1.02 ± 0.10 mb. The process K − n → K ∗0 890 Δ − is observed with cross section 36 ± 9 μ b and t -slope of 10 ± 2 (GeV/ c ) −2 . A kaon diffraction dissociation sample has been obtained, although the Q-signal is not so strong as in experiments with proton targets. Neutron dissociation into n π + π − is also observed with similar properties to those of proton dissociation into p π + π − , but with a broader t -distribution.
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SLOPE FROM FIT TO DN/DT FOR -TP < 0.3 GEV**2.
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