A spin-parity analysis is performed of the low-mass (≤ 1.75 GeV/c2) pπ− system in diffractive np→(pπ−)p using new data at 13 GeV/c and 20 GeV/c. In the context of a Deck-plus-resonances model a good fit to the pπ− angular moments is found only if the Gribov-Morrison parity-change rule does not hold and spin states up to j=52 are included. In particular the presence of a considerable fraction of spin-parity ½− state is indicated.

A partial-wave analysis has been performed on the (K − π − π + ) system produced in the reaction K − p → K − π − π + p at 10 and 16 GeV/ c . In the Q mass region it is found that the two dominant states, K ∗ π and Kπ, both in 1 + S wave, are produced with different polarisations, helicity being approximately conserved in the t -channel for K ∗ π and in the s -channel for Kπ. This is in contradiction with the assumption that the amplitude can be factorised into “production” and “decay” parts, and hence that the two amplitudes are fully coherent. The phase variation of the two states do not indicate simple resonance behaviour. It is concluded that the Q-mass enhancement is composite.

A partial-wave analysis has been performed of the diffractively produced low-mass ( K ̄ 0 π − π 0 ) system in the reaction K − p → ( K ̄ 0 π − π 0 ) p at 10 and 16 GeV/ c . Thus information complementary to that derived from the K − p → (K − π + π − )p) channel is obtained. The presence of the K ϱ decay mode, besides the dominant K ∗ (890)π mode, for the state J P = 1 + , is confirmed. It is also confirmed that for this 1 + state the assumption of factorization of the amplitude into “production” and “decay” does not hold: the two decay modes K ∗ π and K ϱ have different polarisation properties (helicity is approximately conserved in the t -channel for the first, in the s -channel for the second). The assumption that the ( K ̄ 0 π − π 0 ) system has isospin I = 1 2 has been tested and found to hold. From the cross sections for the various J P states, assuming I = 1 2 , the cross sections for the (K − π + π − ) system are predicted and compared with the experimental ones. In general, agreement is found.

The polarization P in proton-proton elastic scattering has been measured at 3.83 GeV/ c for 0.35 ⩽ | t | ⩽ 3.0 (GeV/ c ) 2 , i.e. 29° ⩽ θ c.m. ⩽ 93°. The polarization shows a minimum at − ⋍ 1.0 ( GeV /c) 2 followed by a maximum at −⋍1.5 ( GeV /c) 2 . At the same energy the spin rotation parameter R has been measured in the interval 0.18 ⩽ | t | ⩽ 0.57 (GeV/ c ) 2 . Comparison with the results at 6.0 and 15.75 GeV/ c shows a similar t -dependence and the same average value at all three energies.

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We have performed a partial-wave analysis of the mainly diffractively produced low-mass (K ππ ) system in the reactions K − p → K − π + π − p and K − p → K 0 π − π 0 p at 10, 14 and 16 GeV /c . We find that the dominant 1 + S ( K ∗ π ) state has possibly a two-peak structure (around 1.27 and 1.37 GeV). In contrast the 1 + S(K ϱ ) state shows one narrow peak near thershold (around 1.27 GeV). These states are found to be of different origin. The results favour the interpretation of the 1 + S(K ϱ ) as a 1 + resonance below the (K ϱ ) threshold. The t ′ pp dependence is found to be different for the 1 + and 0 − states.

The inclusive production of Σ + (1385) and Σ − (1385) has been studied in K − p interactions at 10 and 10 and 16 GeV/ c . It is found that the cross sections for the reactions K − p → Σ ± (1385) + anything are approximately constant in the energy range form 10 to 32 GeV/ c , being ≈ 350 μ b for Σ + (1385) and ≈ 250 μ b for Σ − (1385). The d σ d p ⊥ 2 distributions for Σ ± (1385) fall off exponentially with increasing p ⊥ 2 , with sloped of about 3 (GeV/ c ) −2 . The d σ /d x distributions for Σ + (1385) and Σ − (1385) are markedly different: the production of Σ − (1385) is symmetrical forwards and backwards in the c.m.s.; for Σ + (1385), the distribution is the same as for Σ − (1385) in the forward direction, but presents a large excess of events in the backward direction. This indicates that for the production of both Σ + (1385) and Σ − (1385) the fragmentation of the incoming kaon is negligible. The fragmentation of the target proton is negligible for Σ − (1385), but it is important for Σ + (1385) and is responsible for the excess (∼100 μ b) of its cross section over that for Σ − (1385).

We present a systematic analysis of the production of K ∗+ (892) and Δ ++ (1236) resonances in the K + p → K 0 p π + reaction at 5, 8.25 and 16 GeV/ c . We have measured total cross sections, differential cross sections, density matrix elements and examined resonance production mechanisms in terms of the exchange of states with definite naturality. Some results on the reaction K + p → K ∗+ (1420) p are also given.

The energy dependence of the modulus and phase of the K L 0 -K S 0 regeneration amplitude on hydrogen in the range of 14–50 GeV has been investigated at the Serpukhov 70 GeV accelerator. It has been established that the modulus of the modified regeneration amplitude decreases with increasing momentum as 2|ƒ 21 0 (p)|/k = (0.84 ± 0.42) · p −0.50±0.15 mb . The amplitude phase is energy-independent and its mean value is ϕ 21 0 = −132° ± 5°. The results obtained are compared with other experiments and with predictions of different theoretical models.

The production of η(550) and ω(780) mesons is studied in π ± p interactions at 16 GeV/ c and K − p interactions at 10 and 16 GeV/ c . Cross sections for exclusive channels are presented, and for the π + p data differential cross sections are given for quasi-inclusive production where the η or ω is required to be accompanied by charged particles only. Close similarities are observed between η, ω and also ϱ 0 (770) production in terms of longitudinal and transverse variables. By a rough estimate, the η, ω and ϱ 0 inclusive yields are found to be in the ratio 0.32 : 0.85 : 1, respectively, for 16 GeV/ c π + p collisions. For non-peripheral production we estimate this same ratio to be 0.34 : 0.9 : 1.