H. Filthuth

K−p cross sections from440 to 800 MeV/c

Abstract K − p reactions have been studied at 19 different momenta between 436 and793 MeV/ c . This interval corresponds to a mass of theK¯N system from 1535 to 1695 MeV. About 400 000 photographs were taken in the 81 cm Saclay hydrogen bubble chamber exposed to a separated K − beam at the CERN proton-synchrotron. A total of about 100 000 events were analysed, from which partial and differential cross sections were determined. Polarizations were obtained for the two-body reactions where the decay of the Λ or Σ hyperon allowed their measurement. Data for all the channels are presented here.

Elastic Σ±p scattering at low energies

Abstract Total and differential elastic Σ ± p scattering cross sections have been measured in the momentum interval of 130–180 MeV/ c . From the Σ ± p total cross section allowed regions for the singlet and triplet scattering lengths are derived, applying the effective range approximation.

Inelastic Σ−p-interactions at low momenta☆

The total cross-sections for the two reactions Σ−p → Λn and Σ−p → Σ°n in the momentum intervall 105 ⩽pgS− ⩽ 165 MeV/c are presented. For the process Σ−p → Λn the differential cross-section and the Λ-polarization are given.

The KN interaction from 800 to 1200 MeV/c (I). K−p cross sections

K−p reactions have been studied at 23 different momenta between 777 and 1226 MeV/c. This interval corresponds to a mass range of the KN system from 1688 to 1897 MeV. About 350 000 photographs were taken in the 81 cm Saclay hydrogen bubble chamber, exposed to a separated K− beam at the CERN proton synchrotron. A total of about 100 000 events were analysed and partial and differential cross sections were determined; polarisations were also obtained for those reactions where the decay of the Λ or Σ+ hyperon allowed their measurement. The data for all the channels are presented here except those corresponding to two-prong configurations, which make the subject of a separate investigation.

A new determination of the Ko → π+π− decay parameters

Abstract In a short neutral beam we have measured the proper time-dependence of the decay K o → π + π − . This time structure exhibits the interference between the short- and long-lived states and is in agreement with the general expectations of the CP violation phenomenology. This experiment gives new and more precise measurements of the following three parameters: 1. i) the decay width of the short-lived K S component: Γ S = (1.119±0.006) × 10 10 sec −1 ; 2. ii) the modulus of the CP violating parameter η +- : | η +- | = (2.30±0.035) × 10 −3 ; 3. iii) the phase of η +- as a function of the K S −K L mass difference Δm : φ +- = (49.4±1.0) o + [( Δm −0.540)/0.540] × 305 o The result of |η +- | may be compared with the result of the foregoing letter on Re ϵ in the frame of the superweak model. Good agreement is observed.

A fit of baryon decay rates within SU(3)

Abstract A test of the consistency between observed resonant amplitudes or decay rates for baryon resonances with SU(3) predictions has been made. Coupling constants describing the decays are determined and predictions are given for decays into stable baryons and mesons.

A NEW DETERMINATION OF THE K0 ---> pi+ pi- DECAY PARAMETERS

Abstract In a short neutral beam we have measured the proper time-dependence of the decay K o → π + π − . This time structure exhibits the interference between the short- and long-lived states and is in agreement with the general expectations of the CP violation phenomenology. This experiment gives new and more precise measurements of the following three parameters: 1. i) the decay width of the short-lived K S component: Γ S = (1.119±0.006) × 10 10 sec −1 ; 2. ii) the modulus of the CP violating parameter η +- : | η +- | = (2.30±0.035) × 10 −3 ; 3. iii) the phase of η +- as a function of the K S −K L mass difference Δm : φ +- = (49.4±1.0) o + [( Δm −0.540)/0.540] × 305 o The result of |η +- | may be compared with the result of the foregoing letter on Re ϵ in the frame of the superweak model. Good agreement is observed.

The reactions K−p → K−p and K−p → Kon between 600 and 1200 MeV/c

Data on K−p → K−p, K− → Kon and on the K−p total cross section between 600 and 1200 MeV/c are analysed in terms of resonant and non-resonant partial-wave amplitudes.

Energy-independent partial-wave analysis of KN → Λπ between 600 and 1200 MeV/c

Abstract The reactions K−p → ΛπO and K−n → Λπ− in the centre-of-mass energy range from ≈1.6 to ≈1.9 GeV have been interpreted in terms of an energy-independent partial-wave analysis. Solutions are presented and the possible existence of new resonant states is discussed.

New experimental results on the reactions K−p → KN and K−p → Σπ and a partial-wave analysis between 430 and 800 MeV/c

The reactions K−p → K−p, K0n and K−p → Σ+π−, Σ0π0, Σ−π+ have been studied in the c.m. energy range 1530 – 1700 MeV; new experimental data are presented and results of an energy-dependent partial-wave analysis are discussed.