In an experiment with the 30-inch Hybrid Spectrometer at Fermilab we have obtained the inclusive and semi-inclusive production cross sections of the ϱ0 meson using a conventional background subtraction technique. Production cross sections for the ϱ0 are derived as a function of the Feynman scaling variablex, and the transverse variablespt2 andEt=(pt2+M2)1/2. The longitudinal distributions are compared with the (1−x) dependence of the proton and meson valence quark structure functions, using various forms of recombination and fragmentation models. The transverse distributions are compared with thermodynamic models. We give density matrix elements for the ϱ0 production from pions in the extreme forward region.
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The energy dependence of the average of the charged multiplicity and its dispersion in π + /K + /p interaction on protons at 147 GeV/ c is found to be the same as in e + e − annihilations if an “effective energy” variable is used instead of the total energy. The effective energy S eff is defined as the invariant mass of all secondaries left after the two leading particles have been removed. Fitting the expression aS eff b to the average charge multiplicity 〈 n ch 〉, we find the power b to be in good agreement with the value of 0.25 predicted by Fermi's statistical model and by Landau's hydrodynamical model.
BINS IN WEFF SELECTED SO AS TO YIELD 200 EVENTS IN EACH BIN.
200 EVENTS IN EACH BIN IN WEFF.
50 EVENTS IN EACH BIN IN WEFF.
The polarization of the recoil proton has been measured in both high-energy elastic and inclusive proton-proton scattering at the internal-target area of Fermi National Accelerator Laboratory. The polarization in elastic scattering was measured at a number of center-of-mass energies up to s=19.7 GeV. Indications of negative polarization were seen at the higher center-of-mass energies for t values of -0.6, -0.8, and -1.0 (GeV/c)2. In the inclusive process p+p→p↑+X the polarization was found to be independent of beam energy from 100 to 400 GeV for xF values of -0.7, -0.8, -0.9. The polarization at PT=1.0 GeV/c, xF=−0.7 and xF=−0.8 was less than 2.5%. This is significantly lower than the corresponding measurements reported for Λ0 inclusive polarization.
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Results are presented from a study of inclusive neutral strange particle production by a 147 GeV/ c tagged π + /K + /p beam in the Fermilab 30-inch hydrogen bubble chamber. The experiment made use of the proportional hybrid spectrometer system. Results are based on 995 K S 0 , 485 Λ, and 83 Λ found in a sample of 132 000 pictures. Cross sections are given for inclusive production of these particles by each of the three beam particles, and comparisons are made with measurements at other energies. Topological cross sections are also calculated, and KNO multiplicity scaling is investigated. Distributions are presented of invariant cross sections as functions of the Feynman scaling variable x and c.m. rapidity y . The transverse momentum-squared distributions with their fitted slopes are also given. Comparisons are made of the production characteristics for the three beam types.
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The results of an experiment conducted at Fermilab to measure the polarization of the final-state proton in the reaction p+p→p↑+X and p+C→p↑+X are presented. Measurements were made at beam energies of 100, 200, 300, and 400 GeV for PT from 0.5 to 1.5 GeV/c and xF between - 0.7 and - 0.9.
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The reactions π+p→Σ+(1385)K+ and π+p→Σ+(1385)K*+(890) are examined. The Σ+(1385)K+ differential cross section for −t′<0.5 GeV2 and spin density matrix elements agree with a Regge-pole model incorporating (nondegenerate) vector and tensor K* exchange with dominant M1 coupling. The Σ+(1385)K*+(890) density matrix elements are consistent with the quark-additivity predictions. A Y*+ at a mass of 1700 MeV is also observed in the Λπ+ mass distribution, produced opposite both K+ and K*+(890).
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GOTTFRIED-JACKSON FRAME.
We have measured the ratio of inclusive production of η to π0 at transverse momenta above 1.5 GeV/c. Results are presented for various meson and proton beams with momenta of 100, 200, and 300 GeV/c incident upon a hydrogen target. The ηπ0 production ratio is found to be independent of incident beam momentum and of the transverse and longitudinal momenta of production. The ratio for pion- and proton-induced reactions is 0.44 ± 0.05; for kaons, it is 0.74 ± 0.12.
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Cross sections are presented for production of final states with two strange particles from π+p interactions at 10.3 GeV/c in a 31.1-event/μb bubble-chamber experiment.
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The differential cross sections for K+d coherent, breakup, and charge-exchange scattering have been measured at several momenta in the interval 250-600 MeV/c. The data have been fitted using a partial-wave analysis. Assuming an s-wave description of I=1 scattering and using data from the coherent and charge-exchange channels, a description of I=0 K+−N scattering by a combination of s and p waves in a simple single-scattering impulse model has been attempted. The phase shifts obtained are unique up to the Fermi-Yang ambiguity, which can be removed by using existing polarization results at 600 MeV/c.
COHERENT SCATTERING DIFFERENTIAL CROSS SECTION IN THE LABORATORY FRAME.
COHERENT SCATTERING DIFFERENTIAL CROSS SECTION IN THE LABORATORY FRAME.
COHERENT SCATTERING DIFFERENTIAL CROSS SECTION IN THE LABORATORY FRAME.
New results are presented from the continuation of an experiment designed to study the polarization in elastic p−p scattering at large four-momentum transfers. A high-intensity unpolarized proton beam of momentum 12.3 GeV/c was incident on a propanediol polarized proton target and both final-state protons were detected and momentum-analyzed in multiwire proportional chamber spectrometers. The measurements spanned the t range 1.5<|t|<6.2 (GeV/c)2. The results are discussed in the framework of optical, exchange, and parton models.
INCLUDING DATA FROM AN EARLIER RUN (ABSHIRE PRL 32, 1261 (1974)) FOUND TO BE IN STATISTICAL AGREEMENT.
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