High-statistics data on the reaction π−p→ηπ+π−n at 8.06 GeV/c were obtained. An isobarmodel partial-wave analysis was performed for the ηππ system. The η(1275) meson was confirmed as a narrow IJPC=00−+ resonance. It decays through both δπ and εη. A narrow state with IJPC=00−+ was found in an ηππ decay channel at 1.42 GeV. It has a prominent peak in a δπ decay mode. No significant E(1420) signal with IJPC=01++ was found near the mass region of 1.42 GeV.
No description provided.
We have obtained a sample of 20 465 (2201) events in the channel pp→ ( Λ 0 K + )p at 50 (30) GeV/ c incident momentum with Geneva-Lausanne spectrometer at the CERN SPS. In this analysis we investigate: 1. (i) the production of N ∗ (I = 1 2 ) states in the mass region 1.6 ⩽ M ( Λ 0 K + ) ⩽ 2.6 GeV and momentum transfer 0.06 ⩽ | t | 1.0 (GeV/ c ) 2 , by studing the amplitudes and phases from a moment analysis of the decay angular distribution; 2. (ii) the contribution of the K-exchange Deck model for M ( Λ 0 K + < 2.22 GeV; 3. (iii) the double Regge exchange phenomenology for s Λ 0 K + > 5 GeV 2 and s Λ 0 K + p > 5 GeV 2 .
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The K π − system produced in the reaction K p → K 0 π − p at 4.2 GeV/ c is studied using high-statistics bubble-chamber data. The spin-parity structure is analysed as a function of the K 0 π − mass up to 1.52 GeV. Production of K ∗ (890) and K ∗ (1420) is observed in helicity-0 and helicity-1 states. Contributions of natural and unnatural parity exchange are present. Considerable S-wave production is observed over the whole mass region considered. We also study the t ′ dependence of the K ∗ (890) and K ∗ (1420) amplitudes. A comparison of our results on K ∗ (890) production with the results of an analysis of charge-exchange K ∗ (890) production, allows the separation of I = 0 and I = 1 exchange amplitudes. Some qualitative remarks are made concerning K ∗ (1420) production.
No description provided.
PARTIAL WAVE ANALYSIS ASSUMING SPIN-COHERENCE TO OBTAIN SPIN-PARITY STRUCTURE AND T DEPENDENCE OF P-WAVE AND D-WAVE AMPLITUDES.
The modulus and the phase of the K L o −K S o regeneration amplitude on carbon have been measured. In a momentum range of 16–40 GeV/ c the phase is constant within experimental error bars and coincides with the regeneration phase on hydrogen. Both the modulus and the phase of the regeneration amplitude on carbon are in agreement with optical model predictions.
ASSUMING A CONSTANT PHASE INDEPENDENT OF MOMENTUM, THE CARBON REGENERATION AMPLITUDE HAS A PHASE OF -130 +- 17 DEG.
The real part of the forward amplitude for Compton scattering on protons was measured through the interference between the Compton and Bethe-Heithler amplitudes by detecting the zero-degree electron pairs asymmetrically. The measurement was made at an average photon energy of 〈k〉=2.2 GeV, and an average momentum transfer to the recoil proton 〈t〉=−0.027 (GeV/c)2. The result confirms the prediction of the Kramers-Kronig relation.
No description provided.
Elastic and inelastic K L S regenerative scattering on copper and lead nuclei have been observed up to a momentum transfer of 0.17 GeV/ c . The elastic differential cross-section is of a ”diffractive” type. It can be described successfully in terms of an optical model only assuming an appreciable neutron excess in the vicinity of the nuclear surface.
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The interference between K L → π + π - and K S → π + π - behind a copper regenerator has been observed in a high statistics experiment. The modulus and the argument of the complex ratio ϱ ( p )/ η +- , where ϱ ( p ) is the regeneration amplitude and η +- = A ( K L → π + π - )/ A (K S → π + π - ) has been measured over the momentum interval from 2.0 GeV/ c to 6.0 GeV/ c . The phase of η +- as deduced from this measurement and from the optical model value of arg [ ϱ ( p )] is 49.3° ± 6.8°. The K L K S mass difference has been found to be Δm/ h ̵ = (0.555 ± 0.020) × 10 10 sec −1 .
No description provided.
The transmission regeneration amplitude after a thick copper block has been measured. The quantity {∣ƒ(0)- overlineƒ(0)∣ }/{k} varies from 20.0 $\pm$ 1.4 mb at 2.75 GeV/c to 13.6 $\pm$ 1.2 mb at 7.25 GeV/c. Results are in agreement with optical model calculations in which real and imaginary parts of the amplitudes for single nucleon scattering are determined from forward dispersion relations and total cross-sections.
Regeneration amplitude.
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