We present results on an amplitude analysis of the K + K − system produced in the reaction π − p→K + K − n from threshold up to 2.2 GeV. The branching ratios of f 0 and f' to K K have been determined. In the low mass region of the K K system the observation of an S-wave enhancement at 1.3 GeV and the interference of the f 0 -A 2 -f' mesons are studied. We observe a 3 − structure in the mass region of 1.7 GeV which is consistent with g 0 production. With this interpretation the branching ratio g→ K K has been determined. Evidence for a new structure in the J p = 2 + wave around 1.8 GeV with a width of ∼200 MeV is presented.
HELICITY ZERO D-WAVE AMPLITUDE FITTED BY SUM OF BREIT-WIGNER RESONANCES. F 14 GIVES T-DEPENDENCE. ALSO EVIDENCE FOR 1.8 GEV STATE WITH 0.60 +- 0.13 MUB PRODUCTION CROSS SECTION.
FROM HELICITY ZERO F-WAVE AMPLITUDE ASSUMING PREDOMINANTLY G(1680)0 PRODUCTION. F 16 GIVES T-DEPENDENCE.
The reaction π − p→K + K − n has been studied on a hydrogen target (27 000 events) at 18.4 GeV/ c and on a polarized target (54 000 events) at 17.2 GeV/ c . A combination of results of both experiments allows a partial-wave analysis of the K + K − system between 1.1 and 1.74 GeV mass without any model assumptions. In general our fits yield unique solutions. Using results of our previous analysis of π + π − final states and assuming the dominance of the positive G -parity states in the K + K − system, the branching ratios BR ( K K /ππ) of partial waves into K K and ππ are determined. The S-wave appears to be mainly a broad ε (1300) with BR ( K K /ππ) = 0.068 −0.021 +0.017 . The weak P-wave can be described by a tail of the ϱ(770) with BR ( K K /ππ) = 0.081 −0.025 +0.029 . The D-wave is interpreted in terms of a superposition of f(1270) + A 2 (1310) + f′(1515) resonances. The fit yields BR ( K K /ππ) = 0.069 −0.031 +0.023 for the f(1270) and BR( ππ /all) = 0.027 −0.013 +0.071 for the f′(1515). The F-wave shows the g(1690) meson with BR ( K K /ππ) = 0.191 −0.037 +0.040 . All the above values refer to the t bin between 0.01 and 0.20 (GeV/ c ) 2 . Some results are also given for the high- t region.
PARTIAL-WAVE INTENSITIES AND BRANCHING RATIOS.
We have studied backward meson and baryon production in π−p→nπ+π− at 8 GeV/c using a streamer chamber triggered by the detection of the interaction of the neutron in thick-plate optical spark chambers. Our data sample of 866 events is dominated by the quasi-two-body final states Δ−(1232)π+, nρ0, and nf0. We study the differential and total backward cross sections for these states and the decay angular distributions of the resonances. The results for the Δ− and ρ0 indicate that both nucleon and Δ exchange in the u channel are important in their production, while f0 production is, as expected, consistent with nucleon exchange.
No description provided.
BACKWARD DIP.
No description provided.
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