B.Y. Oh

A formation study of NN interactions between 1.09 and 3.45 GeV/c (II). Strange particles☆

Abstract A systematic study of p p and p d reactions producing strange particles between 1.09 and 3.45 GeV/ c has been completed. Reaction and resonance cross-section data are presented at 11 p p and 13 p d momentum settings. Evidence for a broad shoulder in the K K 3π final state near 1.8 GeV/ c is presented and contrasted to previously published work on a portion of the final data sample. No evidence for a p n → K 0 K − ω effect near 1.3 GeV/ c is found, ruling out an association of K K ω effects with the nearby isospin one enhancement in the total cross section. Finally, we find no evidence for a p p → K K ω enhancement near 1.8 GeV/ c .

A formation study of NN interactions between 1.51 and 2.90 GeV/c (I). Topological and reaction cross sections☆

Abstract A systematic study of p p and p d topological and reaction cross sections between 1.51 and 2.90 GeV/c has been completed. The data have been analysed in relation to the three known structures at c.m. N N energies of 2190, 2350 and 2375 MeV. The data suggest that four- and six-pion annihilations of antiprotons on neutrons may be the source of the 2350 MeV effect. Further data below 1.60 GeV/c are required to verify this tentative conclusion.

General features of charged particle production in pp interactions at 100 GeV/c

Abstract We present new data on charged particle production in p p interactions at 100 GeV/c. Comparisons are made between p p annihilations (estimated by differences) between corresponding p p and pp data samples) and e+e− annihilation into hadrons. A technique for separating the inclusive proton and pion spectra is described and the resulting pion spectra are studied in terms of Feynman x, rapidity and pT. Comparison with pp data allows us to estimate the pion spectra in p p annihilations and we find agreement with predictions of Mueller-Regge theory. We also present results on semi-inclusive π± and proton production, give updated topological cross sections and describe further attempts to isolate effects due to annihilations. Finally we investigate the diffractive excitation of the antiproton into low-mass states by studying events with a slow recoil proton.

Inclusive study of Λ0 and Σ± hyperons produced in proton-proton collisions from 6.6 to 28 GeV/c☆

Abstract Inclusive production of Λ 0 , Σ + and Σ − hyperons has been studied in proton-proton interactions from 6.6 to 28 GeV/ c . Cross sections rise rapidly from 6.6 to 13 GeV/ c . Above approximately 20 GeV/ c the cross sections appear to have reached a scaling limit in the laboratory longitudinal momentum variable q L and the c.m. Feynman variable x . There is no detectable polarization of the Λ 0 as a function of - t at all energies. Laboratory production differential cross sections are presented.

Inclusive production of π0, Ks0, Λ0, and Λ0 in 100, 200 and 360 GeV/c π−p interactions

Inclusive cross sections for π0, Ks0, Λ0 and Λ0 production in 100, 200 and 360 GeV/c π−p interactions are presented and compared with data at other energies. Invariant cross sections for γ, Ks0, Λ0 and Λ0 production are presented in terms of Feynman x, the rapidity y, and transverse momentum squared, pT2. A comparison of the observed γ spectrum is made with the spectra computed assuming that the π0 momentum distribution is identical to that of the observed π+ orπ−.

Antiproton-proton elastic scattering from 1.51–2.90 GeV/ c

Abstract In a bubble chamber experiment, we have measured p p elastic scattering at nine momenta in the range 1.51–2.90 GeV/ c . The extrapolation of the small angle region to t = 0 is discussed and compared with results of other experiments. The differential cross sections are fitted to an adaptation of the Frahn-Venter optical model and also compared to Regge-pole model predictions.

Two particle correlations in the central region of pp and π−p interactions at 100–300 GeV/c

Abstract Significant positive correlations are seen for all charge combinations of pion pairs with small rapidity separation. Joint rapidity-azimuthal correlations show that this positive correlation occurs when like (unlike) pions are produced with small (large) separation in azimuth.

ρ0production inπ−pinteractions at 100, 200, and 360 GeV/c

Inclusive and semi-inclusive cross sections for rho/sup 0/ production in 100, 200, and 360 GeV/c ..pi../sup -/p interactions are presented. Differential cross sections for rho/sup 0/ production as functions of c.m. rapidity and transverse momentum are compared with the corresponding differential cross sections for pion production. Effects of various methods of estimating background on the values obtained for rho/sup 0/ production cross sections are discussed. About 10% of the final-state charged pions appear to come from rho/sup 0/ decay. Thus, while rho/sup 0/ production and decay is a significant source of final-state pions, other sources must contribute the majority of the produced pions.

Differences betweenp¯pandppinteractions at 8.8 GeV/cand their relationship top¯pannihilations

We report on an experiment in which the SLAC 40-in. hybrid facility was exposed to an 8.8-GeV/c antiproton beam. Using external detectors we have identified a large fraction of nonannihilation events and thus obtained a clean sample of annihilation data. Using proton interactions taken in the same detector at the same energy we have made a detailed study of (p-barp-pp) differences and explored their relationship to p-barp annihilations.

Study of the reaction K−p→φφΛ at 8.25 GeV/c

Abstract In a high statistics bubble chamber study the reaction K − p → φφΛ is detected with a cross section of 0.7±0.2 μ b. The ratio of φφ production in K − and π − induced reactions is found to be ∼5; this is about ten times smaller than the ratio for the corresponding single φ production reactions.