The total cross section difference Δα L (pp) for proton-proton scattering with beam and target polarized longitudinally parallel and antiparallel, respectively, has been measured using the polarized proton beam from SATURNE II and a frozen spin polarized proton target. The beam polarization was reversed from pulse to pulse, and at each energy Δα L was measured for both signs of target polarization. The data below 800 MeV confirm the previously observed structures. The cross section difference is found to change by 8.0 ± 0.5 mb between 520 MeV and 760 MeV. At the higher energies the results show no indication for similar structures or for a change of the sign of Δα L .

The spin correlation parameter A oonn and the analyzing powers A oono and A ooon were measured simultaneously, in the energy range 0.5–0.8 GeV and in the angular region 40°–80° CM. The experiment used the polarized proton beam of SATURNE II and the Saclay frozen spin polarized target.

The results presented in this paper were obtained from a 105 000 frame exposure of the FNAL Hybrid Proportional Wire Chamber-30 inch Bubble Chamber System, in a tagged beam of 147 GeV/ c negative particles. Elastic, total and topological cross sections were obtained for both π − p and K − p interactions. Comparisons with other data, taken with various beam particles over large momentum intervals, show good agreement with KNO scaling, and similarity in the scaling behavior of σ n for the different beam particles.

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Results are presented on π + p and K + p elastic scattering at 250 GeV/ c , the highest momentum so far reached for positive meson beams. The experiment (NA22) was performed with the european hybrid spectrometer. The π + p elastic cross section stays constant with energy while the K + p cross section increases.

We studied 21 187 two-prong, two-prong-with-kink, and zero-prong-V events at incident kaon momentum of 1.33 GeVc using the 72-in. hydrogen bubble chamber at the Lawrence Radiation Laboratory and two scanning and measuring projectors in Urbana. We determined the total and partial cross sections for all contributing reactions. For the two-body final states, some production and polarization angular distributions were measured. The angular distributions are discussed in terms of exchanges in the kinematical channels s, t, and u assuming the simplest Feynman graphs. Elastic scattering is analyzed as a diffraction process.

Approximately 700 events of the reaction K − d → K − π − pp s produced by 5.5 GeV/ c kaons were used to measure the cross section for Kπ elastic scattering in the T = 3 2 state by a Chew-Low extrapolation. The cross section does not exceed 2.1 mb and has no structure for Kπ masses from threshold up to 2.0 GeV.

We present the results on total channel cross-sections obtained in the Saclay 180 l HBC exposed to a separated K− beam at Nimrod. The cross-sections for each channel are given at 13 incident K− momenta between 1.26 and 1.84 GeV/c.

The results on total channel cross-sections obtained in the 2 m HBC exposed to a separated K− beam at the CERN PS are presented here. The total cross-sections for each channel are given at seven incident K− momenta between 1.934 and 2.516 GeV/c.

In an experiment on K--proton interactions in a hydrogen bubble chamber, the cross sections and angular distributions have been studied for elastic and charge-exchange scattering, and charged sigma hyperon production in the momentum range 90-300 MeV/c. Good agreement is found with previous cross sections except for the charge-exchange channel where the new values are 60% larger. The production distributions of the charged sigma hyperons and the polarisation of the Sigma + hyperon clearly indicate that P waves are present down to about 150 MeV/c, much lower than previously reported.

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Results are reported based on a study of π − p interactions at 147 GeV/ c in the FERMILAB 30-inch Proportional Wire Hybrid Bubble Chamber System. We have measured the topological cross sections and separated two-prong elastic and inelastic channels. In addition, we have extracted leading particle cross sections using the increased momentum resolution of the downstream proportional wire chambers. We have compared our results with experiments and predictions of a simple fragmentation hyphothesis.

The Fermilab hybrid 30-in. bubble-chamber spectrometer was exposed to a tagged 147-GeV/c positive beam containing π+, K+, and p. A sample of 3003 K+p, 19410 pp, and 20745 π+p interactions is used to derive σn, 〈n〉, f2cc, and 〈nc〉D for each beam particle. These values are compared to values obtained at other, mostly lower, beam momenta. The overall dependence of 〈n〉 on Ea, the available center-of-mass energy, for these three reactions as well as π−p and pp interactions has been determined.

In a single-arm spectrometer experiment, high-precision measurements of dσdt for π−p, K−p, and p¯p elastic scattering have been made at 8 and 16 GeV/c. The π−p data show rich structure at 8 GeV/c, indicative of strong non-Pomeron contributions, while the 16-GeV/c data are much smoother. For −t≳1 (GeV/c)2 there is a strong s dependence while there is very little for −t<1 (GeV/c)2. For p¯p scattering the forward region is smoothly diffractive for −t<0.4 (GeV/c)2 and shows antishrinkage. The exponential slope parameter b is measured to be 12.36 ± 0.04 (GeV/c)−2 at 8 GeV/c and 11.40 ± 0.04 (GeV/c)−2 at 16 GeV/c. The structure near −t=0.6 (GeV/c)2 seen at lower energies is still obvious at 16 GeV/c. The K−p data show some structure at 8 GeV/c, but can be represented adequately by a quadratic exponential form. At 16 GeV/c the K−p angular distribution shows antishrinkage and lies above the 8-GeV/c cross section for 0.11<−t<0.8 (GeV/c)2.

K − p elastic scattering at 10 GeV/ c is studied on ∼3600 bubble chamber events. The elastic cross section is found to be σ el = (3.20 ± 0.14)mb and the ratio σ el σ tot = (0.142 ± 0.006) , that is below the upper limit of 0.185 suggested in a model by Van Hove. The value of the forward differential cross section is consistent with zero real part to the scattering amplitude. The slope of d σ d t is similar to that for π ± and greater than that of K + , with no evidence for shrinkage of the diffraction peak. No events of backward scattering were observed. The Regge-pole model of Phillips and Rarita gives a good fit to the data.

Results are presented on elastic scattering of 10.1 GeV/ c K − mesons on protons, based on a sample of 16 261 kinematically-fitted bubble-chamber events. The differential cross section is given over the | t |- range of 0.06 to 2.5 GeV 2 and is fitted with the expressions a e bt , A e Bt + Ct 2 and ( P e Qt + Re St ) over various intervals of t . The results are compared with those of other experiments at nearby energies. Upper limits of | α | < 0.28 and σ B < 0.4 μ b (both at a 90% confidence level) are given for the ratio of real to imaginary part of the forward-scattering amplitude and the backward-elastic-scattering cross section, respectively.

We have measured π+p, π−p, and pp elastic scattering at an incident-beam momentum of 200 GeV/c in the region of −t, four-momentum transfer squared, from 0.021 to 0.665 (GeV/c)2. The data allow an investigation of the t dependence of the logarithmic forward slope parameter b≡(ddt)(lndσdt). In addition to standard parametrization, we use functional forms suggested by the additive quark model to fit the measured dσdt distributions. Within the context of this model we estimate the size of the clothed quark in the pion and proton. Limits on the elastic-scattering amplitude derived from unitarity bounds are checked, and no violations are observed.

The differential cross sections for the elastic scattering of π+, π−, K+, K−, p, and p¯ on protons have been measured in the t interval -0.04 to -0.75 GeV2 at five momenta: 50, 70, 100, 140, and 175 GeV/c. The t distributions have been parametrized by the quadratic exponential form dσdt=Aexp(B|t|+C|t|2) and the energy dependence has been described in terms of a single-pole Regge model. The pp and K+p diffraction peaks are found to shrink with α′∼0.20 and ∼0.15 GeV−2, respectively. The p¯p diffraction peak is antishrinking while π±p and K−p are relatively energy-independent. Total elastic cross sections are calculated by integrating the differential cross sections. The rapid decline in σel observed at low energies has stopped and all six reactions approach relatively constant values of σel. The ratio of σelσtot approaches a constant value for all six reactions by 100 GeV, consistent with the predictions of the geometric-scaling hypothesis. This ratio is ∼0.18 for pp and p¯p, and ∼0.12-0.14 for π±p and K±p. A crossover is observed between K+p and K−p scattering at |t|∼0.19 GeV2, and between pp and p¯p at |t|∼0.11 GeV2. Inversion of the cross sections into impact-parameter space shows that protons are quite transparent to mesons even in head-on collisions. The probability for a meson to pass through a proton head-on without interaction inelastically is ∼20% while it is only ∼6% for an incident proton or antiproton. Finally, the results are compared with various quark-model predictions.

We present results from a high-momentum-resolution measurement of the π-p elastic differential and total cross-sections-at values of cos θ* between — 0.60 and 0.85 in the centre-of-mass system and at incident-beam momenta between 1.34GeV/c and 1.49 GeV/c—close to the X0 production threshold. There is no significant enhancement near the X0 production threshold. However, a small effect of ~ 3 standard deviations is present, having mass 1898.8 MeV and width ~5MeV, and appearing at an incident-pion momentum of 1435 MeV/c. In addition, a narrow ~ 5-standard-deviation effect atEc.m.= 1876 MeV appeared at an incident-pion momentum of 1389 MeV/c.

Total and differential cross sections are presented for the reactions K − p → K − p and K − p → K o n at 13 points in the c.m. energy range 1915–2168 MeV. An energy-dependent partial-wave analysis is carried out on these data together with the polarisation measurements of Daum et al. [1] and the total cross section measurements [2] within this energy range. The well known Σ(1915), Σ(2030) and Λ(2100) are observed and their resonance parameters measured. Structure is also found in the D 05 and F 07 waves. An SU(3) analysis of the 5 2 + octet, 7 2 + decuplet and 7 2 − singlet gives generally good agreement between theory and experiment except that the elasticity of the Σ(1915) is experimentally rather larger than predicted.

The elastic scattering of 3.6 GeV/ c π + mesons by protons has been studied in a hydrogen bubble chamber experiment. The elastic cross section has a measured value of 7.07 ± 0.20 mb. The forward diffraction peak has been fitted in the region 0.05 ≦ − t ≦ 0.6 (GeV/ c ) 2 by a form (d σ /d t ) = Ae Bt , where A = 46.5 ± 1.8 mb/(GeV/ c ) 2 and B = 6.85 ± 0.20 (GeV/ c ) −2 . From this fit and the optical theorem, the magnitude of the ratio of real to imaginary forward amplitude is 0.39 ± 0.06, in reasonable agreement with dispersion relation calculations and simple Regge model predictions.

New data on the K−p elastic and charge exchange reactions are presented in the K− momentum range between 1.934 GeV/c and 2.516 GeV/c. A conventional energy-dependent partial-wave analysis covering the widerPK- range from 1.6 GeV/c to 2.516 GeV/c is presented together with a p.w.a. in which the duality ands-helicity conservation ideas are explicitly imposed in the fits. Finally the new Y*’s observed in this experiment are classified inSU3 multiplets.

π−p elastic scattering is studied at an incident π− beam momentum of 3.92 GeV/c. From the analysis of about 38 000 elastic events we give the differential cross-section for −t>0.06 (GeV)2. The known structures at −t ≈ 0.8 and 2.8 (GeV)2 are seen. An additional possible structure is present in the backward hemisphere.

Cross sections and charged multiplicity distributions forK+p interactions at 70 GeV/c are presented and compared withK+p data at other energies. Comparisons are also made with available π+p,pp, andK−p data.

In this letter results are presented on the reactions K − p → K 0 n and K − p → K − p from a high statistics CERN 2-metre hydrogen bubble chamber exposure at 4.15 GeV/ c . The behaviour of the differential cross section as a function of four-momentum transfer shows remarkable similarities between the two reactions studied. From a comparison of our data with K + p elastic scattering at 4.27 GeV/ c we draw some conclusions concerning the magnitude of the contributing amplitudes.

We present preliminary results on the measurement of a variety of exclusive hadron interactions at center of mass scattering angles of 90°. Data are also presented which show the relative transparency of nuclei to πp and pp elastic scattering in this kinematic range.

Measurements are reported of the differential cross section for the reaction π − +p→ ω +n from threshold to a final-state c.m. momentum P ∗ of 200 MeV /c . The previously reported fall in total cross section σ/P ∗ below about 100 MeV/ c is again seen. The differential cross section remains close to isotropic over the entire range. A paralle experiment on the variation in the elastic differential cross section across the threshold shows evidence of this threshold. The elastic data cover a range of incident moments from 1010 to 1180 MeV/ c in steps of 5 MeV/ c .

From an experiment done with the CERN Omega spectrometer, triggered by a fast forward proton device, we present results on the differential cross section d σ d u for π − p backward elastic scattering. The d σ d u distribution agrees with an A e Bu law. The compilation of existing results shows a discrepancy between results but the ( d σ d u ) u=0 data fit perfectly an s 2 α 0 −2 dependence, as predicted by a single Δδ Regge trajectory exchange. A search for the reaction π − p → d p , with a fast forward deuteron, which can be produced by a double-baryon exchange mechanism, gives cross-section upper limits of ∼1% of the backward elastic cross section.

K − p reactions have been studied at 13 different incident momenta between 1138 and 1434 MeV/ c . This interval corresponds to a mass of the K − p system varying from 1858 to 1993 MeV. About 300 000 photographs were taken in the 81 cm Saclay hydrogen bubble chamber exposed to a separated K − beam at the CERN proton-synchrotron. A total of about 44 000 events were analyzed, from which partial and differential cross sections were determined. Polarizations were obtained for the two-body reactions where the decay of the Λ or Σ hyperon allowed their measurement. Data for the two-body channels are presented here as well as for the main quasi-two-body reactions.

The absolute luminosity of the CERN Intersecting Storage Rings has been determined by the Van der Meer method. Combining the measurement with small angle proton-proton elastic events, we find σ elastic = (6.8±0.6)mb.

The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The implementation of a central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements. Thus all pion production channels were recorded with 1-4 overconstraints. The total and differential cross sections obtained are compared to previous data and theoretical calculations. Main emphasis is put on the discussion of the $pp\pi^0$ channel, where we obtain angular distributions different from previous experimental results, however, partly in good agreement with recent phenomenological and theoretical predictions. In particular we observe very large anisotropies for the $\pi^0$ angular distributions in the kinematical region of small relative proton momenta revealing there a dominance of proton spinflip transitions associated with $\pi^0$ $s$- and $d$-partial waves and emphasizing the important role of $\pi^0$ d-waves.

K + p elastic scattering is studied at incident K + beam momenta of 2.53, 2.76 and 3.20 GeV/ c . From the analysis of about 10 000 elastic events at each energy, we present data on the forward and backward elastic scattering peaks. No structure is observed in the forward peak for − t ⩽ 2 (GeV/ c ) 2 . In addition, the statistics available from this exposure permit a measurement of the differential cross sections near 90° in the center of mass system. These results exhibit a strong energy dependence and are compared to similar results at other energies.

Results are presented on the topological cross sections obtained for antiproton-proton interactions from an exposure of the Fermilab 30-inch bubble chamber to a 100 GeV/ c negative beam enriched in p 's. The p p inelastic cross section is found to be σ inel = 34.6 ± 0.4 mb, and the average inelastic charged particle multiplicity to be 〈 n 〉 = 6.74 ± 0.05.

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Invariant single-particle cross sections for pion and proton production in π ± p interactions at 8 and 16 GeV/ c are presented in terms of integrated distributions as functions of x , reduced rapidity ζ and p ⊥ 2 , and also in terms of double differential cross sections E d 2 σ /(d x d p ⊥ 2 ) and d ζ d p ⊥ 2 ). A comparison of π ± and π − induced reactions is made and the energy dependence is discussed. It is shown that the single-particle structure function cannot be factorized in its dependece on transverse and longitudinal momentum. For the beam-unlike pion, there is an indication for factorizability in terms of rapidity and transverse momentum in a small central region.

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We have analyzed the two-prong final states in π+p interactions at 3.9 GeVc. Our result for elastic scattering is σ (elastic) = 6.50±0.1 mb (statistical error only). We find the elastic slope to be 6.61±0.14 (GeVc)−2. We find the elastic forward cross section to be 40.0±1.4 mb(GeVc)2. We have applied a longitudinal-momentum analysis to the one-pion-production channel. We find the cross section for the reaction π++p→π++π0+p to be 2.30±0.06 mb and that for π++p→π++π++n to be 1.45±0.05 mb. For resonance-production cross sections in these channels we find Δ(1236)=0.60±0.07 mb, ρ(760)=0.86±0.06 mb, and diffraction dissociation = 1.69±0.11 mb. We find that we can satisfactorily fit all distributions in the one-pion-production channel without assuming any phase-space production. In the missing-mass channel we observe dominant Δ++(1236) production plus evidence for A2+ production.

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A study of pp interactions at an incident momentum of 16.2 GeV/ c leading to two-prong non-strange final states was carried out in an exposure of the 2m CERN hydrogen bubble chamber. The c.m. angle and momentum distributions for the outgoing particles in the final states pn π + and pp π 0 are presented and discussed. These final states were analysed in terms of quasi two-body final states - N(Nπ), with the pion-nucleon system in an I = 1 2 or I = 3 2 state. A determination of these two isospin amplitudes and their interference term is then carried out. The reaction pp → pn π + is found to be well described by a Reggeized exchange model, as well as by a double Regge-exchange model.

In a special run of the LHC with $\beta^\star = 2.5~$km, proton-proton elastic-scattering events were recorded at $\sqrt{s} = 13~$TeV with an integrated luminosity of $340~\mu \textrm{b}^{-1}$ using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam $t$ variable in the range from $-t = 2.5 \cdot 10^{-4}~$GeV$^{2}$ to $-t = 0.46~$GeV$^{2}$ using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section $\sigma_{\textrm{tot}}$, parameters of the nuclear slope, and the $\rho$-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit $t \rightarrow 0$. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the $t$-dependence. The results for $\sigma_{\textrm{tot}}$ and $\rho$ are \begin{equation*} \sigma_{\textrm{tot}}(pp\rightarrow X) = \mbox{104.7} \pm 1.1 \; \mbox{mb} , \; \; \; \rho = \mbox{0.098} \pm 0.011 . \end{equation*} The uncertainty in $\sigma_{\textrm{tot}}$ is dominated by the luminosity measurement, and in $\rho$ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.

Baryon resonance production in quasi-two-body reactions has been studied for the channels K + p→K°p π + , K + n π + and K + p π ° at beam momenta of 2.53, 2.76 and 3.20 GeV/ c . The production cross sections, four-momentum transfer distributions and density matrix elements are given for the Δ(1236), N ∗ (1400), N ∗ (1500) and N ∗ (1680) states. The reaction K + p→K° Δ ++ (1236) is compared to the line reversed reaction K − n → K °Δ − and the charge-exchange SU(3) sum rule for pseudo-scalar meson plus Δ(1236) is tested.

Report on the investigation of interactions in π−p collisions at a pion momentum of 1.59 GeV/c, by means of the 50 cm Saclay liquid hydrogen bubble chamber, operating in a magnetic field of 17.5 kG. The results obtained concern essentially the elastic scattering and the inelastic scattering accompanied by the production of either a single pion in π−p→ pπ−π0 and nπ−π+ interactions, or by more than one pion in four-prong events. The observed angular distribution for the elastic scattering in the diffraction region, can be approximated by an exponential law. From the extrapolated value, thus obtained for the forward scattering, one gets σel= (9.65±0.30) mb. Effective mass spectra of π−π0 and π−π+ dipions are given in case of one-pion production. Each of them exhibits the corresponding ρ− or ρ0 resonances in the region of ∼ 29μ2 (μ = mass of the charged pion). The ρ peaks are particularly conspicuous for low momentum transfer (Δ2) events. The ρ0 distribution presents a secondary peak at ∼31μ2 due probably to the ω0 → π−π+ process. The branching ratio (ω0→ π+π−)/(ω0→ π+π− 0) is estimated to be ∼ 7%. The results are fairly well interpreted in the frame of the peripheral interaction according to the one-pion exchange (OPE) model, Up to values of Δ2/μ2∼10. In particular, the ratio ρ−/ρ0 is of the order of 0.5, as predicted by this model. Furthermore, the distribution of the Treiman-Yang angle is compatible with an isotropic one inside the ρ. peak. The distribution of\(\sigma _{\pi ^ + \pi ^ - } \), as calculated by the use of the Chew-Low formula assumed to be valid in the physical region of Δ2, gives a maximum which is appreciably lower than the value of\(12\pi \tilde \lambda ^2 = 120 mb\) expected for a resonant elastic ππ scattering in a J=1 state at the peak of the ρ. However, a correcting factor to the Chew-Low formula, introduced by Selleri, gives a fairly good agreement with the expected value. Another distribution, namely the Δ2 distribution, at least for Δ2 < 10 μ2, agrees quite well with the peripheral character of the interaction involving the ρ resonance. π− angular distributions in the rest frame of the ρ exhibit a different behaviour for the ρ− and for the ρ0. Whereas the first one is symmetrical, as was already reported in a previous paper, the latter shows a clear forward π− asymmetry. The main features of the four-prong results are: 1) the occurrence of the 3/2 3/2 (ρπ+) isobar in π−p → pπ+π−π− events and 2) the possible production of the ω0→ π+π−π0 resonance in π−p→ pπ−π+π−π0 events. No ρ’s were observed in four-prong events.

Experimental results are presented for the available channels in the 1.2 GeV/ c π + p interaction. An isobaric model with incoherent addition of the amplitudes is used to determine the π, Δ and N ∗ abundance rates in the π + π o p final state. The multipole parameters in the density matrix of the Δ ++ are determined as functions of its production angle.

Results of a high-statistics study of elastic scattering and meson resonances produced by π−p interactions at 8 GeV/c are presented. Large statistics and small systematic errors permit examination of the complete kinematic region. Total differential cross sections are given for ρ0,−, f0, g0,−, Δ±, Δ0, and N* resonances. Spin-density matrix elements and Legendre-polynomial moments are given for ρ, f, and Δ resonances. The results for ρ0 and f0 resonances are compared with the predictions of a Regge-pole-exchange model. Properties of the above resonances are compared and discussed. In particular, we present evidence that the ρ0 and f0 production mechanisms are similar. The similarity of the g0 t distribution to that of the ρ0 and f0 suggests a common production mechanism for all three resonances.

The Brookhaven National Laboratory twenty-inch liquid hydrogen bubble chamber was exposed to a monoenergetic beam of 2.85-Bev protons, elastically scattered from a carbon target in the internal beam of the Cosmotron. All two-prong events, excluding strange particle events, have been studied by the Yale High-Energy Group. The remaining interactions have been studied by the Brookhaven Bubble Chamber Group. Elastic scattering was found to be mostly pure diffraction scattering at center-of-mass angles up to about thirty-five degrees. Some phase shift and/or tapering of the proton edge was required to fit the data at larger angles. No polarization effects in the proton-carbon scattering were observed using hydrogen as an analyzer of polarized protons. Nucleonic isobar formation in the T=32, J=32 state was found to account for a large part of single pion production. High-orbital angular-momentum states were found to be greatly favored in single pion production. The isobar model of Lindenbaum and Sternheimer gave good agreement with the observed nucleon and pion energy spectra. No polarization or alignment effects were observed for the isobar assumed in this model.

Results are reported concerning the charged-particle multiplicity distribution obtained in an exposure of the high-resolution hydrogen bubble chamber LEBC to a beam of 800 GeV protons at the Fermilab MPS. This is the first time that such data have been available at this energy. The distribution of the number n ch of charged particles produced in inelastic interactions obeys KNO-scaling. The average multiplicity is 〈 n ch 〉 = 10.26±0.15. For n ch ⩾8 the data can be well fitted to a negative binomial. The difference between the overall experimental multiplicity distribution and that resulting from the latter fit is in agreement with the contribution expected from diffractive processes.

Results are presented onK+p elastic scattering and on the reactionK+p→K+pπ+π− at 70 GeV/c. For the

The charged-particle multiplicity distribution in 205−GeVc proton-proton interactions is presented. In addition, the total diffractive contributions to each charged multiplicity are estimated assuming a factorizable Pomeron.

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About 3700 two-prong and 5600 four-prong events of 10-GeV/c pp interactions in the Saclay 81-cm hydrogen bubble chamber have been measured and analyzed. The reliability of the identification of the different final states has been checked using Monte Carlo-generated events. For the channels accessible to analysis, cross sections and invariant-mass distributions are given. The c.m. angular distributions and the mean values of the transverse momentum for all final-state particles are shown and discussed. Production of Δ++(1236) accounts for about 30% of the cross section σ(pp→pnπ+)=4.1±0.4 mb. About 50% of the cross section σ(pp→ppπ+π−)=2.4±0.2 mb can be accounted for by Δ++ production. Production of nucleon isobars at 1450, 1520, and 1730 MeV and their subsequent decay into pπ+π− are investigated. Their cross sections, t dependences, and branching ratios are determined, using a one-pion-exchange model (OPEM) for calculating the background distributions. The production of resonances decaying into pπ− at 1236, 1500, and 1690 MeV is seen, and cross sections are given. Resonance production in the ppπ+π−π0 and pnπ+π+π− reactions is studied using background curves calculated with a model based on simple parametrizations of the c.m. momentum distributions. The production of nucleon isobars accounts for nearly 100% of these reactions. For the reactions pp→ppω, ppη, and ppf0, the cross sections found are 0.16±0.03, 0.16±0.07, and 0.10±0.04 mb, respectively, corrected for unobserved decay modes. It is shown that most of the gross features of the pion-production reactions can be explained by the OPEM with the form factors of Ferrari and Selleri.