Inclusive cross sections and one-particle inclusive spectra are given for neutral K, Λ and Λ produced in K − p and K + p interactions at 32 GeV/ c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. Cross sections for associated production are also given, and the energy dependences of the cross sections and of the x distributions in the central and in the fragmentation regions are discussed.
Inclusive cross sections and longitudinal momentum distributions are presented for γ rays produced in K − p and K + p interactions at 32 GeV/c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. The average longitudinal and transverse momentum of neutral pions and the average π 0 multiplicity ▪ 〈 n π 0〉 are estimated. It is found that 〈 n π 0〉 is an increasing function of the number of charged prongs.
Inclusive Δ++(1236) production in π+p and pp interactions is consistent with one-pion exchange. The average charged multiplicity recoiling from the Δ++ is studied as a function of missing mass, M2, for both interactions.
A very narrow resonance with a mass of 3.1 GeV/c2 is observed in the reaction n+Be→μ++μ−+X. The total cross section for this process, as well as its P⊥2 and x distribution, are given.
A very narrow resonance with a mass of 3.105 GeV/c2 is observed in the reaction γ+Be→μ++μ−+X. The total cross section for this process, as well as its t distribution, is given.
Results are presented of a study of inclusive ηp and ηn interactions from threshold to 6 GeV. The data show a rapid approach to the distributions expected in the naive quark-parton model. The charged-current η deuteron total cross section is fit by the expression σ T ( η d) = (0.76 ± 0.03) × 10 −38 E η cm 2 per GeV per nucleon. For E η > 1.5 GeV, we measure σ T ( η n)/ σ T ( η p) = (2.02 ± 0.23). The distributions in the scaling variables x and y are given and discussed.
We have measured the total cross-section difference for pp scattering in initial spin states parallel to the beam direction at beam momenta of 1.17, 1.47, 1.69, 1.97 and 2.49 GeV/ c . This measurement was done in a standard transmission experiment. A striking energy dependence is observed with a maximum difference of −16.9 mb at P lab = 1.47 GeV/ c .
The K L o p → K S o p differential and total cross-section and the forward scattering amplitude phase φ have been measured in the 1.5 to 2.3 GeV centre of mass energy range. The data is compared with predictions based on recent K ± N phase shift solutions. Best agreement is found for K + N solutions which do not warrant an I=0 P 1 2 exotic Z ∗ o (1800) baryon.
A partial wave analysis of the non-diffractively produced ( K ̄ 0 π + π - system has been performed. The system was produced in the reaction K - p→ K ̄ 0 π + π - n at 10 GeV/ c , measured in the CERN Omega spectrometer. Besides the well-known K ∗ (1420) resonance, we find good evidence for the production of Q 2 (1400) and some indication for Q 1 (1290) production in J P =1 + . In addition we clearly observe a bump in the 1800 MeV region, the properties of which are discussed.
The ratio R of the differential cross sections for π - p→ η ′n and π - p → η n has been measured with high statistics and small systematic errors at 8.45 GeV/ c . R is generally interpreted as the relative content of nonstrange, ground-state quarks in η' and η. We find that R decreases with increasing ⋎ t ⋎; however, extrapolation to t =0 gives R (0) = 0.672 ± 0.032 (statistical) ± 0.47 (systematic) for the dominant spin flip cross sections, and R (0) = 0.500 ± 0.035 for the spin non-flip, in excellent agreement with results at higher energy. An improved value of the branching fraction ( η '→ γγ )/( η '→all) of 0.0200 ± 0.0018 is obtained.
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