Cross sections for the $\gamma p \to K^+ \Lambda$ have been measured at backward angles using linearly polarized photons in the range 1.50 to 2.37 GeV. In addition, the beam asymmetry for this reaction has been measured for the first time at backward angles. The $\Lambda$ was detected at forward angles in the LEPS spectrometer via its decay to $p\pi^-$ and the K^+ was inferred using the technique of missing mass. These measurements, corresponding to kaons at far backward angles in the center-of-mass frame, complement similar CLAS data at other angles. Comparison with theoretical models shows that the reactions in these kinematics provide further opportunities to investigate the reaction mechanisms of hadron dynamics.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.5 to 1.8 GeV.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.8 to 2.1 GeV.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 2.1 to 2.4 GeV.
Results of a high-statistics study of elastic scattering and meson resonances produced by π−p interactions at 8 GeV/c are presented. Large statistics and small systematic errors permit examination of the complete kinematic region. Total differential cross sections are given for ρ0,−, f0, g0,−, Δ±, Δ0, and N* resonances. Spin-density matrix elements and Legendre-polynomial moments are given for ρ, f, and Δ resonances. The results for ρ0 and f0 resonances are compared with the predictions of a Regge-pole-exchange model. Properties of the above resonances are compared and discussed. In particular, we present evidence that the ρ0 and f0 production mechanisms are similar. The similarity of the g0 t distribution to that of the ρ0 and f0 suggests a common production mechanism for all three resonances.
No description provided.
No description provided.
SLOPE REFERS TO EXPONENTIAL FIT IN U.
A tagged photon beam and multiparticle spectrometer have been used to measure the backward photoproduction process γp → Δ ++ π − . The energy dependence of the production cross section between 2.8 and 4.8 GeV is studied and found to exhibit shrinkage in excess of that expected for Δ σ dominance. An interpretation of the production mechanism in terms of an incoherent mixture of Δ σ exchange and a “hard scattering” contribution is presented.
No description provided.
In order to determine the ηNN coupling constant we have measured the two reactions K − p→ Λη and K − p→ Λπ 0 with a magnetic wire chamber spectrometer which contained a gamma counter for the γγ decays of π 0 and η. The Λ polarization and the differential cross sections are given. The latter have quite different u dependences. Their ratio is interpreted, in terms of a nucleon-Regge exchange model, as the effect of a small ηNN coupling constant for which we obtain G η NN 2 = G π NN 2 · (0.26 ± 0.10) as allowed by SU(3). The large value given by Heisenberg's non-linear field theory, G η NN 2 = G π NN 2 · 0.9, is excluded by this measurement if the characteristic u dependence of the Λπ 0 channel is attributed to N α Regge exchange.
Axis error includes +- 10/10 contribution.
No description provided.
Axis error includes +- 10/10 contribution.
The reactions p¯p→V0+neutrals were studied in a multiparticle spectrometer at 3.0 GeV/c incident momentum, with a sensitivity of about 150 events/μb. Differential cross sections and polarization of the Λ¯ for the final states Λ¯(Λ) and Λ¯(Σ0) are reported and compared with theoretical models. Differential cross sections of the K0 in K0[K*(890)] and the Λ in Λ(Λ¯+Σ¯0) are also measured. Upper limits of a few μb MeV are obtained for the formation of narrow resonances decaying into V0+neutrals in the mass interval 2.74-2.80 GeV/c2.
FORWARD HEMISPHERE TOTAL CROSS SECTIONS NOT INCLUDING CHARGE CONJUGATE REACTIONS. CORRECTED FOR DECAY BRANCHING RATIOS AND FOR BACKGROUNDS.
No description provided.
No description provided.
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