Proton elastic scattering off a polarized proton target has been measured at 150 GeV/ c , in the |; t |-range 0.2–3.0 GeV 2 . The results on polarization and differential cross section are presented.
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The total cross section for e + e − annihilation into hadronic final states between 3.6 and 5.2 GeV was measured by the nonmagnetic inner detector of DASP, which has similar trigger and detection efficiencies for photons and charged particles. The measured difference in R = σ had / σμμ between 3.6 GeV and 5.2 GeV is ΔR = 2.1 ± 0.3. We observe three peaks at cm energies of 4.04, 4.16 and 4.417 GeV, the parameters of which, when interpreted as resonances, are given.
EXCLUDING CONTRIBUTION OF TAU HEAVY LEPTON.
INCLUDING CONTRIBUTION OF TAU HEAVY LEPTON.
We have analyzed backward meson production in the reaction π − p → p f π + π − π − at 9 GeV/ c and 12 GeV/ c incident π − momenta, from an experiment performed at the CERN Ω Spectrometer using a fast proton (p f ) trigger device. We find strong production of quasi-two-body processes N ∗ ϱ and N ∗ f with a production mechanism consistent with u -channel nucleon exchange. At a lower level, we observe N ∗ π processes with a 3-body baryon decay through Δ(1232)π. In the (3π) − system, we find evidence for A 1 − and clear A 2 − backward production with similar cross sections (≈0.5 μb).
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U-HELICITY JACKSON FRAME.
U-HELICITY JACKSON FRAME.
We present the results and the analysis of a high-statistics experiment to study A 2 and g production in the reaction π − p→K − K S 0 p at 10 GeV/ c . In each resonance region we perform a moment analysis of the data, and from the moments we determine the production amplitudes as a function of t . We find A 2 production proceeds dominantly by natural-parity (pomeron and f) exchange. We compare A 2 and diffractive K ∗ (1420) production. We find g production proceeds by π and ω exchanges; we determine the g → K K branching ratio.
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We have measured π±p and pp elastic differential cross sections in the range |cosθc.m.|<0.35 for incident momenta from 2 to 9.7 GeV/c for π−p and pp and from 2 to 6.3 GeV/c for π+p. We find that the fixed-c.m.-angle πp differential cross sections cannot be described as simple functions of s. The data are compared to the energy and angular dependence predicted by the constituent model of Gunion, Brodsky, and Blankenbecler.
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The photon total cross section on protons has been measured with high precision in the Fermilab tagged-photon beam for photon energies from 18 to 185 GeV. The cross section decreases to a broad minimum near 40 GeV, and then rises by about 4 μb over the remainder of the range. A ρ+ω+ϕ vector-dominance model (normalized to low-energy data) falls below the high-energy results by 2 to 6 μb, suggesting a contribution from charm-anticharm states.
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Invariant inclusive cross-sections for π+-mesons and protons from\(\bar pp\) reactions at 22.4 GeV/c are presented. The average multiplicity for the production of π+-mesons is 1.92±0.02 and for protons 0.41±0.02. Annihilation spectra have been approximated by using the difference between\(\bar pp\) and pp data. The resulting distributions have similar gross features as the total\(\bar pp\) data.
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We have measured the forward production spectra of various neutral particles produced by π−, K−, p¯, and p at 200 GeV/c, and by π− at 290 GeV/c incident on a Be target. The salient features of these measurements are (1) copious production of KSo at large Feynman xL for incident π− and K−, (2) production of roughly equal fluxes of Λ0 and Λ¯0 for incident π−, and (3) close similarity of the following spectra: π−→n and K−→Λ0; π−→Λ0, π−→Λ¯0, and p→KS0; π−→KS0 and p→Λ0. The overall features of the various distributions seem to agree with the ideas of dimensional counting presented in the constituent-interchange model of quark collisions. Results are presented in terms of the invariant cross section Ed3σ(xL, PT=0)dp3 per Be nucleus for each inclusive reaction.
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Large-angle π±p elastic-scattering cross sections, measured between 2 and 9 GeV/c in fine intervals of incident momentum and scattering angle, are used to search for cross-section fluctuations occurring for small changes in the center-of-mass energy as suggested by Ericson and Mayer-Kuckuck and by Frautschi. Significant fluctuations are observed.
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Cross sections have been determined for the inclusive production of vector (ϱ 0 , ω, K ∗ ) and tensor (f, A 2 ± ) mesons in p p reactions at 9.1 GeV/c for both annihilation and non-annihilation processes. Distributions in the Feynman variable x and transverse momentum squared, p T 2 , have been examined for the ϱ 0 , ω and f mesons. The slopes for p T 2 appear to be exponential and decrease with increasing particle mass for both annihilation and non-annihilation reactions, furthermore the slopes have consistently higher values for non-annihilation reactions. Comparisons with other data indicate that the ratio ϱ 0 / π − is independent of antiproton momentum in annihilation processes.
NON-ANNIHILATION EVENTS.
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