Hadron jets produced in e + e − annihilation between 13 GeV and 31.6 GeV in c.m. at PETRA are analyzed. The transverse momentum of the jets is found to increase strongly with c.m. energy. The broadening of the jets is not uniform in azimuthal angle around the quark direction but tends to yield planar events with large and growing transverse momenta in the plane and smaller transverse momenta normal to the plane. The simple q q collinear jet picture is ruled out. The observation of planar events shows that there are three basic particles in the final state. Indeed, several events with three well-separated jets of hadrons are observed at the highest energies. This occurs naturally when the outgoing quark radiates a hard noncollinear gluon, i.e., e + e − → q q g with the quarks and the gluons fragmenting into hadrons with limited transverse momenta.
NORMALIZED TRANSVERSE MOMENTUM DISTRIBUTION WITH RESPECT TO THE SPHERICITY AXIS AT 13, 17, AND 27.4 TO 31.6 GEV.
Results on the hadronic final state in e/sup +/e/sup -/ annihilation at 13, 17 and 27.4 GeV are presented. There is no compelling evidence for the existence of the t quark in these data, which are in general agreement with a simple quark parton model. Some tentative indications of QCD effects are observed in the p/sub T//sup 2/ distributions.
TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED.
INCLUSIVE HADRON SPECTRUM. THESE DATA AT 13, 17 AND 27.4 GEV ON S*D(SIG)/DX ARE INCLUDED IN THE RECORD OF R. BRANDELIK ET AL., PL 89B, 418 (1980).
We have observed e + e − hadrons at C.M. energies of 13 GeV and 17 GeV at PETRA using the TASSO detector. We find R (13 GeV) = 5.6 ± 0.7 and R (17 GeV) = 4.0 ± 0.7. The additional systematic uncertainty is 20%. Comparing inclusive charged hadron spectra we observe scaling between 5 GeV and 17 GeV for x = p / p beam > 0.2; however the 13 GeV cross section is above the 17 GeV cross section for smaller x . This may be due to copious bb̄ production. The events become increasingly jet like at high energies as evidenced by a shrinking sphericity distribution with increasing energy.
TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED.
THESE DATA FOR S*D(SIG)/DX AT 13 AND 17 GEV ARE INCLUDED IN THE RECORD OF R. BRANDELIK ET AL., PL 89B, 418 (1980).
Inclusive V0 production in 6.5-GeV/c K−p interactions is studied using the ANL 12-ft-diameter hydrogen bubble chamber. The total cross sections for inclusive K¯0 and Λ0 production are σ(K¯0)=7.98±0.49 mb and σ(Λ0)=3.94±0.24 mb. Semi-inclusive differential cross sections are determined as functions of Feynman x and transverse momentum squared of the V0's and of four-momentum transfer to the V0. The average charge multiplicity, the ratio 〈nc〉D, and the correlation function f2cc for the neutrally charged hadronic system recoiling from the V0 are determined as functions of the mass of the recoiling system. Results are used to examine universal aspects of multiparticle production.
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The inclusive production of ϱ 0 mesons in pp collisions has been measured at five c.m. energies from √ s = 23.6 to 63.0 GeV. The cross sections and the production spectra as a function of transverse momentum and rapidity are discussed.
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The inclusive cross section for larger p T π 0 production near 90° in p-p collisions at the CERN ISR is presented for centre-of-mass energies 30.7, 53.1 and 62.4 GeV. The data are inconsistent with scaling of the form p T − n F ( x T ), with constant n or with n allowed to depend on x T = 2p T / s . For s = 53.1 and 62.4 GeV , the value of n found for 3.5 < p T < 7.0 GeV/ c is n = 8.0 ± 0.5, in agreement with previous experiments. However, for 7.5 < p T < 14.0 GeV/ c the value becomes n = 5.1 ± 0.4.
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Neutral-pion production in pp interactions has been studied using 8000 photon conversions in the Fermilab 15-ft bubble chamber. Inclusive π0 multiplicity moments and ππ correlation integrals are presented; f200 is determined to be + 3.0±0.8. For the semi-inclusive π0 multiplicity distributions we find 〈n(π0)〉n− to increase with n−, while the dispersions are n− independent. Results on f2−0, f200, and f2,n−00 are compared to predictions of simple cluster models.
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The recoil proton polarization for γ n → π − p was measured around the third resonance region. Both momentum vectors of the proton and the pion were determined by the magnetic spectrometers. The proton polarization was measured by means of proton-carbon scattering in the polarization analyzer located behind the proton spectrometer. Below 900 MeV incident photon energy, our data are consistent with the other existing experimental data ( θ π ∗ = 90° ) and the predictions of partial-wave analyses. Above 1000 MeV, however, a large discrepancy was observed between our data and the predictions of the partial-wave analyses. The discrepancy stands out as the pion c.m. angle increases. A new partial-wave analysis was made for γ n → π − p including our polarization data, and the accuracy of the experimentally determined electromagnetic coupling constant of the third resonances were greatly improved. In particular, a finite amount of the helicity 3 2 amplitude for the γ n → F 15 (1688) resonance was obtained against the predictions of the quark models, by Copley, Karl and Obryk and by Feynman, Kislinger and Ravendal but in agreement with the relativistic quark models of Sugimoto and Toya, and Kubota and Ohta.
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ERRORS INCLUDE BY QUADRATIC ADDITION THE 5 PCT UNCERTAINTY IN THE CARBON ANALYSING POWER.
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