S.M. Flatte

Analysis of the observed anomaly in ππ s-wave scattering near KK̄ threshold

Abstract The character of the ππ s-wave scattering amplitude near 980 MeV is determined from the reactions π + p→‡ ++ π + π − and ‡ ++ K + K − at 7GeV/c.

Observation of an anomally in the π+π− system at 980 MeV

Abstract An anomaly at 980 MeV is seen in both the mass distribution and angular distribution of the π + π − system produced in the reaction π + p → Δ ++ π + π − at 7 GeV/ c . Experimental results for the related final states Δ ++ K + K − , Δ ++ π + π − π + π − and Δ ++ π + π − (neutrals) are presented.

Energy dependence of inclusive distributions in pion-induced reactions☆

Abstract We present data on the inclusive distributions π + p → π ± + anything and π − p → π − + anything at momenta from 3.7 to 18.5 GeV/ c . Distributions are presented in the laboratory, center-of-mass and projectile systems, and the approach to scaling is discussed.

A2 mass spectrum in 7-GeV/c π+p interactions

Abstract The A 2 mass spectrum is studied in the reaction π + p→A 2 + p atZZ 7 GeV/ c in a hydrogen bubble chamber in order to investigate previously reported structure. We report on 1400 A 2 events with mass resolutions of 3.8, 6.7 and 9.2 MeV in the K + K 0 , 3π and ηπ + channels.

Experimental spectra for 12 GeV/c K+p → pK+φ and pK+ω

We present experimental distributions for the reactions K+p → pK+φ, φ → K−K+ and K+p → pK+ω, ω → π−π+π0 at 12 GeV/c. The data were obtained from a 35 events/μb exposure of the SLAC 82-inch HBC. The cross sections for these reactions are (11 ± 1) μb and (47 ± 3) μb. We observe Kφ, Kω, and pω low-mass enhancements with no evidence for narrow structure. The momentum-transfer and angular-decay spectra of these systems are presented.

Branching ratios of the A2+ meson observed in 7 GeV/c π+p interactions☆

Abstract The observed branching fractions of the A 2 + produced in the reaction π + p→A 2 + p at 7 GeV/ c and decaying to ϱπ, ηπ, K K and η′π are presented. The data show no convincing evidence for the decay A 2 + → η ′ π + , the branching fraction being less than 3%. For the other decay modes the values obtained for ϱπ, ηπ and K K are 0.744 ± 0.029, 0.183 ± 0.026 and 0.072 ± 0.012 respectively.

ZENITH-ANGLE DISTRIBUTION OF ATMOSPHERIC MUONS ABOVE 1 TeV.

Abstract The flux of atmospheric muons as a function of momentum and zenith angle is measured for p > 0.3 TeV and 60° θ

A New Kπ Partial Wave Analysis Below 1 GeV Kπ Mass

The Kπ scattering for M(Kπ) < 1 GeV has been studied in the reaction K+p ⇒ Δ++K+π− at 12 GeV/c incident K+ momentum. Both the moments of the Kπ angular distribution and the Kπ cross section are extrapolated to the pion pole, and the results are used in a partial wave analysis. For the s wave we have done both an energy‐independent and an energy‐dependent partial wave analysis. We find that only the so‐called “down” solution is compatible with our data; that is, a phase shift δ01 slowly increasing from 20° at 800 MeV to 60° at 1000 MeV. No evidence for an s‐wave resonance near the K*(890) mass is found, although a resonance with Γ < 7 MeV cannot be excluded by the data. The “down” solution is well represented by an effective range formula with a01 = − 0.33 ± 0.05, in good agreement with a current algebra calculation.