Inclusive production of vector and tensor mesons is studied in a K − p experiment at 32 GeV/ c in the MIRABELLE bubble chamber. The K ∗ 0 (890) , ϱ 0 and ω cross sections are comparable, about 4 mb each. The K ∗ 0 (1420 and cross sections are also comparable, about 1 mb each. The K ∗ o ̈ + (890), Φ, K ∗ o ̈ − (1420) and f cross sections beam fragmentation; ϱ production is almost forward-backward symmetric in the c.m.s. The p T production slopes of K ∗ o ̈ − (890) and ϱ are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ≅50% (≅60%) of final-state pions
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We report on the measurement of the reaction e+e−→e+e− with a large—solid-angle electromagnetic shower detector at center-of-mass energies s=13 and 17 GeV. Comparison of our results with predictions of quantum electrodynamics shows excellent agreement in both the angular distribution and energy dependence. Values of cutoff parameters are also given.
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We present a systematic investigation of channel cross sections in K − p interactions at 32 GeV/ c . The energy dependence of these cross sections is discussed. We also investigate a few non-diffractive two-body reactions. The total cross sections of the two reactions K − p → K ∗− (890) p and K − p → K ∗− (1420) p have a markedly different energy behaviour. There is clear evidence for the reaction K − p → K ∗0 (890) N 0 (1688) ; its differnttial cross section exhibits a sharp forward slope of 24 ± 3 GeV −2 .
FROM AK0 P PI- FINAL STATE.
DOUBLE RESONANCE CHANNEL CROSS SECTIONS FROM BREIT-WIGNER FIT CORRECTED FOR BACKGROUND AND DIFFRACTIVE PROCESSES.
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DATA OBTAINED IN ASSUMPTION THAT RHO(MM=00,P=3,XYZ=SH)=1-2*RHO(MM=1-1,P=3,XYZ=SH).
INTEGRATED CROSS SECTION, INCLUDING SYSTEMATIC UNCERTAINTY IN ERRORS Axis error includes +- 15/15 contribution (DECAY-BR(BRN=OMEGA --> PI0 GAMMA,BR=0.088 +- 0.005)).
We report on the results of the study of e + e − collisions at the highest PETRA energy of √ s = 31.57 GeV, using the 4π sr, electromagnetic and calorimetric detector Mark J. Based on 88 hadron events, and an integrated luminosity of 243 nb −1 we obtain R = σ (e + e − → hadrons)/ σ (e + e − → μ + μ − ) = 4.0 ± 0.5 (statistical) ± 6 (systematic). The R value, the measured thrust distribution and average spherocity show no evidence for the production of new quark flavors.
CORRECTIONS FOR TWO-PHOTON PROCESSES, TAU HEAVY LEPTON PRODUCTION AND INITIAL STATE RADIATIVE CORRECTIONS HAVE BEEN APPLIED.
THRUST DISTRIBUTION (1/N)*DN/DTHRUST AT 31.57 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.
We report the analysis of the spatial energy distribution of data for e+e−→hadrons obtained with the MARK-J detector at PETRA. We define the quantity "oblateness" to describe the flat shape of the energy configuration and the three-jet structure which is unambiguously observed for the first time. Our data can be explained by quantum chromodynamic predictions for the production of quark-antiquark pairs accompanied by hard noncollinear gluons.
AVERAGE OBLATENESS AS A FUNCTION OF SQRT(S) AND OF THRUST AND OBLATENESS DISTRIBUTION (1/N)*DN/DOBLATENESS AT 17 AND 27.4 TO 31.6 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.
Measurements of the reactions e++e−→e++e−, μ++μ−, and τ++τ− at PETRA energies (s12=13,17,27.4,30 and 31.6 GeV) are reported. The results show that these reactions agree well with the predictions of quantum electrodynamics thus determining that all the known charged leptons are pointlike particles to a distance < × 10−16 cm.
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We report the measurement of the reaction e + + e − → hadronic jets at a center-of-mass energy √ s =30 GeV using the MARK-J detector at PETRA. By measuring the energy and angular distribution of both neutrals and charged particles we were able to isolate unambiguously the three-jet events in a kinematic region where the backgrounds from q q and phase space contributions and other processes are small. Various comparisons of the data with quantum chromodynamics were made. The relative yield of three-jet events and the shape distribution of the events enable us to determine α s = 0.23 ± 0.02 (statistical error) with a systematic error of ± 0.04.
OBLATENESS AND THRUST DISTRIBUTIONS FOR NARROW AND BROAD JETS AT 30 GEV. THESE DATA ARE SOMEWHAT ANALYSIS AND DETECTOR DEPENDENT.
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THESE DATA ARE TABULATED IN THE RECORD OF THE PUBLISHED VERSION.
DIVIDE BY 20 TO GET MB/GEV**2.
FROM QUADRATIC EXPONENTIAL FITS TO D(SIG)/DT FOR -T = 0 TO 1.4 GEV**2. SYSTEMATIC ERRORS INCLUDED.
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