Momentum spectra for forward Σ− and Ξ− production by protons on beryllium are presented. Σ− production data for two primary proton momenta are compared to test scaling of the invariant cross section. In addition, the observed single-particle momentum distributions are compared with single-particle spectra from other inclusive reactions initiated by protons.
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Evidence is presented for a new meson resonance at 2340±20 MeV, with a width of 180±60 MeV, decaying primarily into ρρπ. The resonance, which is observed in 15-GeV/c π+p interactions, has isotopic spin 1 or 2 and odd G parity. The cross section for production of the ρρπ state is 7.3±1.7 μb. Branching ratios into ρρπ and other decay modes are given.
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We have measured the polarization parameter and differential cross sections in K+p elastic scattering from a polarized target from small |t| and small |u| at five momentum points: 1.7, 2.1, 2.4, 2.7, and 3.0 GeV/c. The polarized-proton target was butanol cooled at 0.5° by a He3-He4 refrigerator; a combination of multiwire proportional chambers and scintillation counters detected the scattered particles. The results for small |u| are discussed in the context of pure Regge-pole models with exchange-degenerate Λ trajectories.
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We have searched the mass region 3.2 to 5.9 GeV for evidence of narrow resonances in e+e−→hadrons. We find no evidence for any such resonances other than the ψ(3695) in this region with a sensitivity ranging from about 12 to 45% of the integrated cross section of the ψ(3695). The more stringent bounds apply to resonances of a few MeV width, while the looser bounds apply to resonances of up to 20 MeV width.
EXTREAMLY GOOD DATA, MUST BE ASCED FROM AUTHORS.
The angular distribution of 2720 tracks of 1085 hadronic final states produced from (e+e-) annihilation has been studied in the 1.2 to 3.0 GeV total centre-of-mass energy range. If we parametrize the angular distribution in terms off(θ) =1 + A cos2 θ, where 6 is the angle between the hadronic track produced and the colliding-beam direction, the results show thatA is less than 0.21, with 90% confidence.
ANGULAR DISTRIBUTION OF CHARGED HADRONS FOUND TO BE 1 + (0.07 +- 0.11)*(COS(THETA)**2).
The polarized target asymmetry in the reaction γp→π°p has been measured at c.m. angles around 100° for photon energies between 0.4 and 1.0 GeV by detecting both the recoil proton and the π°. The result is compared with recent analyses.
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In this paper a comparison of the general features of the reactions K ± p→Q ± p (1) at incident momentum 8.25 GeV/ c is presented. The relevant data derive from events yielding four-constraint fits to the reactions K ± p→K ± π + π − p in exposures of the CERN 2m HBC to RF-separated K + and K − beams. The (K ππ ) effective mass distributions, production angular distributions in the Q region (1.2⩽ M (K ππ )⩽1.5 GeV) and corresponding decay angular distributions are exhibited, and background effects due to N ∗ and Δ production are systematically studied. In particular, it is found that the distributions d σ /d t ′ and d σ /d t for reactions (1) are adequately described by exponential functions over the interval 0.05–0.35 GeV 2 , and exhibit a cross-over effect for momentum transfer squared −0.1 GeV 2 . For both reactions a flattening of d σ /d t ′ for t ′ < 0.05 GeV 2 is observed. By studying the Chew-Low plots and the effects of the different cuts it was found that this flattening cannot be attributed to amplitudes with net s -channel helicity flip different from zero, at least at these energies.
ABOUT 7 PCT RELATIVE NORMALIZATION UNCERTAINTY FOR K+ AND K- SAMPLES.
FITS TO D(SIG)/DT AND D(SIG)/DTP FOR Q+ AND Q- PRODUCTION TO DETERMINE CROSS-OVER POSITIONS. DATA HAVE MASS CUTS TO SELECT K*0 AND REMOVE DEL++ AND DEL0. MIN IS THE MINIMUM VALUE OF -T FOR THE RELEVANT (K PI PI) MASS.
An amplitude analysis for the reaction π + p → π + π − π 0 Δ ++ at 7 GeV/ c has been performed using the isobar model for the 3 π system. The 3 π -mass covers the range from 0.82 to 1.90 GeV. We observe strong A 2 production. The spin parity of the ω ∗ (1700) is determined to be 3 − . No significant A 1 production can be seen.
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FROM INTEGRATING BREIT-WIGNER FITS TO THE JP=3- AMPLITUDE FOR -T < 0.8 GEV**2.
The inclusive ϱ ° production cross section has been measured in the reaction π − p → π + π − X at 205 GeV/ c . We find σ ( ϱ ° ) = 13.5 ± 3.4 mb, with most of the production occuring in the central region. Assuming σ ( ϱ + ) ≈ σ ( ϱ − ) ≈ σ ( ϱ ° ), it is concluded that approximately one-third of the pions at this energy come from ϱ -decay.
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The single diffraction dissociation process pp → (p π + π − )p has been studied at the CERN ISR at √ s = 45 GeV and 0.1 < − t < 0.6 GeV 2 . The reaction is dominated by nucleon resonance production: pp → pN (1520) and pp → pN(1688) with cross-sections (0.25 ± 0.08) mb and (0.56 ± 0.19) mb respectively.
DIFFERENTIAL CROSS SECTIONS FOR THREE RANGES OF <P PI+ PI-> MASS.
FROM BREIT-WIGNER PLUS BACKGROUND FITS. CORRECTIONS FOR OTHER DECAY MODES USE THE PDG 1974 TABLES FOR N(1520) AND N(1688).
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