A mass-dependent asymmetry was observed in the decay angular distribution of a photoproduced K + K − system near the K + K − threshold. The corresponding moments 〈 Y 1 0 〉 have been evaluated. Interpreting the asymmetry as an S-P wave interface due to the states S 993 ∗ (0 + ) and ø 1019 (1 − ) one can compute the moments 〈 Y 1 0 〉 through an amplitude analysis. The theoretical calculation reproduces the experimental results well, if one assumes a real S-wave amplitude for the S 993 ∗ . The data cannot be explained by a non-resonant real S-wave. Other possibilities have been discussed. An estimate of the photoproduction cross section of the S ∗ → K + K − can be given on the basis of the above hypothesis.
No description provided.
None
OVERALL NORMALIZATION ERROR NOT INCLUDED. -TMIN IS 0.015 (0.023) GEV**2 FOR THE LAMBDA (SIGMA0) REACTION.
INCLUDING NORMALIZATION UNCERTAINTY IN ERRORS. USING EMPIRICAL FITS TO D(SIG)/DT FOR -T > 1.0 GEV**2.
No description provided.
Inclusive cross sections for the production of π ± and K ± mesons in proton-proton collisions have been measured at a c.m. energy √ s = 45 GeV, in the range 0.41 < x < 0.95 and 0.35 < p T < 1.45 GeV, where x = 2 p L/√ s and p L , p T are the longitudinal and transverse components of the momentum of the meson. Within the measured range the p T dependence of the invariant cross section is essentially independent of x and weakly dependent on the type of particle. For all particles the invariant cross sections at fixed p T fall by three orders of magnitude between x = 0.4 and 0.95. Except at the highest values of x and p T , the statistical accuracy is better than 10%. The data are compared with a triple-Regge model and with a simple quark-parton model.
No description provided.
No description provided.
No description provided.
Cross sections, differential cross sections, single and joint spin-density matrix elements are given for the reactions π+p→(ρ0, ω)Δ++ at 10.3 GeV/c. Correlations between the vector-meson and the Δ++ decay angular distributions are observed. A discussion of the results in terms of particle exchange, SU(3) symmetry, quark additivity, and the equal-phase hypothesis is presented. The amplitudes for the process π+p→ρ0Δ++ are extracted by a model-dependent analysis and compared with current theoretical predictions.
P-WAVE BREIT-WIGNER RESONANCES PLUS BACKGROUND USED WITH SLICE TECHNIQUE.
FROM RESONANCE OVERLAP REGION WITH BACKGROUND SUBTRACTED AND NORMALIZED TO TOTAL CROSS SECTION.
FROM RESONANCE OVERLAP REGION WITH BACKGROUND SUBTRACTED AND NORMALIZED TO TOTAL CROSS SECTION.
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).
No description provided.
U-HELICITY JACKSON FRAME.
U-HELICITY JACKSON FRAME.
The pp total cross section difference between pure transverse spin states was measured in the laboratory momentum range 1–3 GeV/ c . Significant differences were found and these differences show striking energy dependence. This structure is in disagreement with the predictions of simple exchange models.
No description provided.
REVISED DATA (J. D. LESIKAR, PRIV COMM, 19 JUN 1981). NOW CORRECTED FOR COULOMB-NUCLEAR INTERFERENCE. IN ADDITION, THE LOWEST MOMENTUM DATA POINT IS NOW KNOWN TO BE IN ERROR.
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.
No description provided.
A search for exotic I=2 hyperons decaying into Σ−π− or Σ−π−π0 has been completed in the final states Σ−π+π− and Σ−π+π−π0 produced in K−n interactions at 2.87 GeV/c. Cross sections for these two final states are 303±31 μb and 660±66 μb, respectively. Upper limits for exotic processes are σ(K−n→Y*−−π+, Y*−−→Σ−π−)<13 μb and σ(K−n→Y*−−π+, Y*−−→Σ−π−π0)<23 μb for Γ(Y*−−)<120 MeV; σ(K−n→Y*−−π+π0, Y*−−→Σ−π−)<28 μb for Γ(Y*−−)<80 MeV. Production cross sections have also been measured for all nonexotic resonances observed in the two final states.
No description provided.
The major production channels of four-prong final states resulting from π+p interactions at a center-of-mass energy of 4.5 GeV are studied. In addition to total production cross sections, comprehensive listings of partial and resonance production cross sections are also given for each final state of interest. All final states, including nπ+π+π+π−, are found to exhibit copious resonance production.
PARTIAL CROSS SECTIONS FROM PI+ P --> PI+ P PI+ PI-.
PARTIAL CROSS SECTIONS FROM PI+ P --> PI+ P PI+ PI- PI0.
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