The reactions K−p → Λπ0, Λη,Λη′ at 4.2 GeV/c (original) (raw)
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Beam-recoil transferred polarizations for the exclusive ep → e ′ K + Λ, Σ 0 reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer Q 2 from 0.7 to 5.4 GeV 2 , invariant energy W from 1.6 to 2.6 GeV, and the full center-of-mass angular range of the K + meson. These new data add to the existing CLAS K + Λ measurements at 2.567 GeV, and provide the first-ever data for the K + Σ 0 channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to s-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the ss quark-pair creation dynamics.
Nuclear Physics A, 1983
A'conplete measurement of the polarization transfer observable has been made for the first time in the (p, ' reaction at intermediate energie. '2~(p,p')12C reaction to tne hasurements are $ repor ed for the 1$ T= 0(12.71 MeV) and 1 , T = 1(15.11 MeV) states at 500 MeV at laborators cattering angles of 3.5°v 5.5°D 7.5°, and 12.0°. Linear combination of these observable are ehown to exhibit a very .s*lectivedependence on the Isoecalar and isovector spirrdependent components of the nucleon-nucleon interaction. To the extent of the validity of the single collision approximation, these amplitudes are cortpareddirectly to the free nucleon-nucleon amplitudes at small momentwn transfers (<1 fr"-l).
Measurement of the p¯p→Λ¯Λ and p¯p→Σ¯ 0Λ+c.c. reactions at 1.726 and 1.771 GeV/c
Physical Review C, 1996
Interest in the production of hyperon-antihyperon pairs following antiproton-proton annihilation stems largely from attempts to understand the nature of flavor production. To date the major focus of both the experimental and the theoretical effort has been on the pp→⌳⌳ reaction. In this paper, we present data on the complementary channels pp→⌺ 0 ⌳ and pp→⌳⌺ 0. Events from the kinematically similar pp→⌳⌳ reaction were obtained in parallel. The procedure to distinguish these three separate reactions is described and results for all channels are presented. These include the total and differential cross sections, hyperon polarizations, and spin correlation coefficients. Data were obtained at incident antiproton lab momenta of 1.726 and 1.771 GeV/c which correspond to excess kinetic energies in the pp→⌳⌺ 0 ϩc.c. reaction of 26 and 40 MeV, respectively, above threshold. Comparisons are made to earlier work at similar excess energies in the pp→⌳⌳ channel. The low-energy regime has been highlighted in this experiment to reduce the complexity in the theoretical analysis. ͓S0556-2813͑96͒01612-3͔
Interest in the production of hyperon-antihyperon pairs following antiproton-proton annihilation stems largely from attempts to understand the nature of flavor production. To date the major focus of both the experimental and the theoretical effort has been on the pp→⌳⌳ reaction. In this paper, we present data on the complementary channels pp→⌺ 0 ⌳ and pp→⌳⌺ 0 . Events from the kinematically similar pp→⌳⌳ reaction were obtained in parallel. The procedure to distinguish these three separate reactions is described and results for all channels are presented. These include the total and differential cross sections, hyperon polarizations, and spin correlation coefficients. Data were obtained at incident antiproton lab momenta of 1.726 and 1.771 GeV/c which correspond to excess kinetic energies in the pp→⌳⌺ 0 ϩc.c. reaction of 26 and 40 MeV, respectively, above threshold. Comparisons are made to earlier work at similar excess energies in the pp→⌳⌳ channel. The low-energy regime has been highlighted in this experiment to reduce the complexity in the theoretical analysis.
Two-prong events in proton-proton interactions at 8.1 GeV/c
Nuclear Physics B, 1969
About 10 000 two-prong events of 8.1 GeV/c proton-proton interactions in the CERN 2 m. bubble chamber have been analyzed. We study elastic scattering and single-pion production reactions. We give cross sections for isobar production. We attempt to interpret the general features of the pp-. pn~ + reaction by the Deck mechanism. We compare the production and the decay of A++(1236) with absorption or ~ Regge trajectory exchange models.
Measurement of the Induced Proton Polarization Pn in the C12(e,e′p→) Reaction
Physical Review Letters, 1998
The first measurements of the induced proton polarization, Pn, for the 12 C(e, e ′ p) reaction are reported. The experiment was performed at quasifree kinematics for energy and momentum transfer (ω, q) ≈ (294 MeV, 756 MeV/c) and sampled a recoil momentum range of 0-250 MeV/c. The induced polarization arises from final-state interactions and for these kinematics is dominated by the real part of the spin-orbit optical potential. The distorted-wave impulse approximation provides good agreement with data for the 1p 3/2 shell. The data for the continuum suggest that both the 1s 1/2 shell and underlying ℓ > 1 configurations contribute.
Measurement of the p ̅ p → K S K S reaction from 0.6 to 1.9 GeV/ c
Physical Review D, 1997
The pp → KsKs → 4π ± cross section was measured at incident antiproton momenta between 0.6 and 1.9 GeV/c using the CERN Low Energy Antiproton Ring (LEAR). This investigation was part of a systematic study of in-flight antiproton-proton annihilations into two-neutral-meson final states in a search for hadronic resonances. A coarse scan of the pp → KsKs cross section as a function of center-of-mass energy between 1.964 and 2.395 GeV/c 2 and a fine scan of the region surrounding the ξ(2220) are presented. Upper limits on the product branching ratio BR(ξ → pp) × BR(ξ → KsKs) are determined for a wide range of mass and width assumptions based on the non-observation of the ξ(2220). A rise in the pp → KsKs cross section is observed near 2.15 GeV/c 2 , which is consistent with the f2(2150) resonance.