We present a comparative study of inclusive and semi-inclusive pion production in pp collisions at 102 and 400 GeV/ c . In particular, we examine the correlation between transverse and longitudinal momentum variables and the energy dependence of invariant cross sections.

Results are given on the inclusive production of charged pions, kaons, and nucleons, in proton-proton collisions at c.m. energies from √ s = 23 to 63 GeV at large angles and for the transverse momentum range 0.1 < p T < 4.8 GeV/ c . The dependence of the production spectra on the collision energy √ s , the transverse momentum p T , and the longitudinal rapidity is discussed.

We have carried out an experimental study of the neutron and proton deep-inelastic electromagnetic structure functions. The structure functions were extracted from electron-proton and electron-deuteron differential cross sections measured in three experiments spanning the angles 6°, 10°, 15°, 18°, 19°, 26°, and 34°. We report primarily on the large-angle (15°-34°) measurements. Neutron cross sections were extracted from the deuteron data using an impulse approximation. Our results are consistent with the hypothesis that the nucleon is composed of pointlike constituents. The variation of the cross section with angle suggests that the hypothetical constituents have spin ½. The data for σnσp, the ratio of the neutron and proton differential cross sections, are in the range 0.25 to 1.0, and are within the limits imposed by the quark model. Detailed studies of the structure functions were made for a range of the scaling variable ω from ω=1.3 to ω=10.0, and for a range of invariant four-momentum transfer Q2 from 1.0 to 20.0 GeV2. These studies indicate that the structure functions approximately scale in the variable ω, although significant deviations from scaling in ω are apparent in the region 1.3<ω<3.3. These deviations from scaling are in the same direction and of similar magnitude for both neutron and proton. The interpretation of the data in terms of various theoretical models is discussed.

We have measured the single-particle inclusive cross sections for p+p→π±+X, K±+X, p+X, p¯+X in the low-p⊥ region (≲ 1.5 GeV/c) as a function of the radial scaling variable XR in p−p collisions at 100, 200, and 400 GeV at Fermilab. The measured π+π− and K+K− ratios are shown to be remarkably similar to the same ratios which have recently been measured at large p⊥ at 90° in the center-of-mass system.

We report measurements of semi-inclusive pion electroproduction from both hydrogen and deuterium targets carried out at the Wilson Synchrotron Laboratory at Cornell University. Measurements were made at the (W, Q2) points (2.15 GeV, 1.2 GeV2), (2.15, 4.0), and (3.11, 1.2) with hydrogen and deuterium, and at (2.15, 2.0), (2.67, 3.3), and (3.11, 1.7) with hydrogen only. The invariant virtual-photoproduction cross section for pions scaled by the total cross section is studied as a function of x′, pT2, W, and Q2. The invariant structure function shows no Q2 dependence and a weak W dependence. The ratio of π+ to π− production is also presented, but a distinction between a universal ω or W dependence cannot be made.

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This Letter reports measurements of the ratios of $\pi$, K, and p production at large values of transverse momentum in $\pi^- −p$ collisions. The charge ratios, such as $\frac {\pi^−} {\pi^+}$, $\frac {K^−} {K^+}$, and $\frac {\overline{p}}{p}$ are seen to be quite different from those measured in p −p collisions. These ratios are sensitive tests of hard-scattering models, and are compared with theoretical predictions. The particle ratios have also been studied as a function of center-of-mass angle ($\theta^*$) at $\theta^*$ = 90°, 77°, and 60°.

Most events with high neutral transverse energy, E T 0 , produced in pp colisions at √ s = 62.3 GeV, are jet-like. The evidence for this is presented, based on data collected using an electromagnetic calorimeter covering 90% of 2π in azimuth. The spectrum d N /d E T 0 has been measured over the E T 0 range from 10 to 35 GeV. Properties of the observed jets are discussed.

Results on the inclusive reactions K − p → K ∗− (890) + X + and K − p → K ∗0 (890) + X 0 at 14.3 GeV/c are presented. A comparison is made with previous data and with the reaction K − p → K 0 + X at 14.3 GeV /c . Predictions of a triple-Regge model for the variation of the unnatural and natural parity exchanges with the mass of the X system are examined. The experimental values of the structure functions are compared with those calculated from a quark model.

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The distribution of total tranverse energy ΣE T over the pseudorapidity interval −1 < η < 1 and an azimuthal range Δφ =300° has been measured in the UA2 experiment at the CERN p p collider ( s = 540 GeV ) using a highly segmented total absorption caloriter. In the events with very large ΣE T (ΣE T ⪆60 GeV ) most of the transverse energy is found to be contained in small angular regions as expected for high transverse momentum hadron jets. We discuss the properties of a sample of two-jet events with invariant two-jet masses up to 140 GeV c 2 and we measure the cross section for inclusive jet production in the range of jet transverse momenta between 15 and 60 GeV c .

A measurement of the nucleon structure function F 2 on iron is presented. The data cover a kinematic range of 3.25 ⪕ Q 2 ⪕ 200 GeV 2 and 0.05 ⪕ x ⪕ 0.65 . The data clearly show scaling violation. Fits in leading-order QCD have been made and values for the scale breaking parameter λ are given.

The proton structure function F 2 has been measured in the range 2.5 ⪕ Q 2 ⪕ 170 GeV 2 and 0.03 ⪕ x ⪕ 0.65 . Scaling violation is clearly seen in the data. Results of fits to leading-order QCD are presented, together with values of the scale-breaking parameter λ.

With a segmented total absorption calorimeter of large acceptance, we have measured the total transverse energy spectrum for pp̄ collisions at s 1 2 = 540 GeV up to ΣE T = 130 GeV in the pseudo-rapidity range | η |< 1.5. Using two different algorithms, we have looked for localized depositions of transverse energy (jets). For ΣE T > 40 GeV , the fraction of events with two jets increases with Σ E T ; this event structure is dominant for ΣE T > 100 GeV. We measure the inclusive jet cross section up to E T (jet) = 60 GeV and the two-jets mass distribution to 120 GeV/ c 2 . The measured cross sections are compatible with the predictions of hard scattering models based on QCD.

We report measurements of the inclusive electroproduction reaction e+p→e+p+X for protons produced between 100° and 150° in the virtual-photon-target-proton center-of-mass system. Data were taken at the (W,Q2) points (2.2 GeV, 1.2 GeV2), (2.2, 3.6), (2.65, 1.2), (2.65, 2.0), (2.65, 2.8), (2.65, 3.6), (3.1, 1.2), and (3.1, 2.0). The invariant structure function is studied as a function of W, Q2, xT, pT2, and MX2.

We present high-statistics results on the reactions a+p→c+X where a and c can be any of π±, K±, p, or p¯. The data were taken at 100 and 175 GeV/c incident momenta using the Fermilab Single-Arm Spectrometer operated over the kinematic range 0.2<x<1.0 and pt<~1.0 GeV/c. Investigating the x dependence of the data, we find agreement with a quark-parton picture, namely the cross sections have a power-law behavior in 1−x independent of pbeam and pt.

Correlations between pions produced in pp collisions at 69 GeV/c are observed both for π−π+ and π−π−. Short-range correlations in rapidity are present fory1⋍y2 in both cases; an enhancement is seen aroundy1=y2=±1. Correlations between transverse variables are linked to those in rapidity for π−π− combinations, whereas the effect is essentially kinematical for π+π−.

The inclusive cross sections for π − , π 0 , π + and η production in K − p interactions at 14.3 GeV/ c are calculated. The invariant cross section distributions are presented and compared in the whole phase space for π + and π 0 , and in the backward c.m. region for π − . In the fragmentation regions, the charged pion production is analysed in terms of the triple-Regge model.

Measurements of the cross section for the reaction p+p→π0+anything have been completed. The data cover a range of incident proton energies 50-400 GeV, π0 transverse momenta 0.3-4 GeV/c, and laboratory angles 30-275 mrad. The experiment was performed using the internal proton beam at the Fermi National Accelerator Laboratory. A lead-glass counter was used to detect photons from the decay of π0's produced by collisions in thin targets of hydrogen or carbon. Tables of the measured cross sections are presented.

We present data on π0 and η inclusive production from 100-GeV/c π±p collisions in the kinematic region x>~0.7 and 0<−t≲4 (GeV/c)2. The results are in excellent agreement with the predictions of triple-Regge theory and we have extracted the ρ and A2 trajectories out to −t=4 (GeV/c)2.

We compare high-transverse-momentum (P⊥) inclusive π0 production from π−, K−, p, and p¯ beams, at 100 and 200 GeV/c, for center-of-mass (c.m.) angles ranging from 2° to 115° and P⊥<4.5 GeV/c. The ratio σ(pp→π0X)σ(πp→π0X) decreases with increasing P⊥, and changes dramatically with c.m. angle. Also, the ratios σ(K−p→π0X)σ(π−p→π0X) and σ(p¯p→π0X)σ(pp→π0X) are approximately constant. These measurements are consistent with a theoretical viewpoint in which constituents of the incident hadrons undergo a hard-scattering subprocess.

Inclusive charged-current interactions of high-energy neutrinos and antineutrinos have been studied with high statistics in a counter experiment at the CERN Super Proton Synchrotron. The energy dependence of the total cross-sections, the longitudinal structure function, and the nucleon structure functionsF2,xF3, and\(\bar q^{\bar v} \) are determined from these data. The analysis of theQ2-dependence of the structure functions is used to test quantum chromodynamics, to determine the scale parameter Λ and the gluon distribution in the nucleon.

The properties of the diffractive peak observed in the mass spectra of systems recoiling against observed high-momentum protons emerging from pp collisions at the CERN ISR have been investigated. The cross sections in this peak have been found to have a steep t dependence which flattens out as | t | increases. The high mass side of the peak varies approximately as 1/ M 2 (where M is the missing mass of the recoiling system) and scales well in terms of the variable M 2 / s . The position of the maximum has been observed to move to lower values of M 2 / s as the kinematic boundary of this variable decreases with increasing s . The measured cross sections, integrated up to M 2 / s =0.05, rise by (15±5)% over the s range 549 to 1464 GeV 2 .

Inclusive production of ifπ ± , K ± and p has been studied near charm threshold for c.m. energies between 3.6 and 5.2 GeV. Differential and scaling cross sections together with particle multiplicities have been determinated. By comparing data below and above charm threshold the charm contribution to if π ± and K ± production has been extracted. A comparison has been made between inclusice p production and inelastic electron-proton scattering. To study differences between three-gluon annihilation and two-quark production of the spectra from J/ decay and from non-resonant production at 3.6 GeV has been compared.

The production of enutral kaons in e + e − annihilation has been measured for c.m. energies between 3.4 GeV and 7.6 GeV. Near 4 GeV the inclusive K S cross section shows an increase and structure similar to total hadron production. Roughly 40–45% of all hadronic final states contain kaons, except at 4.028 GeV and 4.415 GeV, where a significantly larger kaon fraction is observed.

New data for the reaction e + e − →ϒ(9.46) have been obtained using the DASP detector at the DORIS storage ring. The electronic width Γ ee is (1.5±0.4) keV. The branching ratio for the decay into muon pairs is (2.5 ± 2.1)%. Energy spectra for inclusive production of hadrons are given.

The inclusive production of Ξ + and Ξ − hyperons is investigated in K + p interactions at 32 GeV/ c . The production cross sections, 36.4±9 μ b for the Ξ + and 6.5±3 μ b for the Ξ − , are rising strongly with energy similarly to Λ and Λ production in K + p interactions. The Ξ + are produced preferentially in the forward direction in the c.m.s., while the Ξ − are produced dominantly backwards. The average transverse momenta 〈p T 〉 Ξ + =0.73±0.09 GeV /c and 〈 p T 〉 Ξ − =0.58±0.09 GeV/ c .

Using data from the Fermilab 15 ft hydrogen bubble chamber, we have studied inclusive ϱ 0 production in antineutrino-proton charged-current interactions. We measure (0.21 ± 0.03) ϱ 0 /event, corresponding to ϱ 0 / π − =0.12 ± 0.02. As a function of Q 2 and for hadronic masses above a threshold region, the ϱ 0 / π − ratio shows little variation. At least 50% of the ϱ 0 's are consistent with coming from the current fragmentation region. The results agree reasonably well with the predictions of the quark fragmentation model of Feynman and field.

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Inclusive ϱ 0 and φ production is investigated in K + p interactions at 32 GeV/ c . Total and semi-inclusive ϱ 0 and φ cross sections, longitudinal and transverse momentum distributions, including 〈 P T versus x dependence are presented. No evidence for a sea-gull effect is observed. Comparison with quark models strongly suggests the possibility that a large fraction of the ϱ 0 and vector mesons are produced as fragmentation products of the incident particles. Study of uncorrelated π + π − pairs in the ϱ 0 mass range provides possible indirect evidence for the existence of diquarks in the proton.

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Results are presented on two-particle inclusive production inK+p interactions at 32 GeV/c. We study thex1,2=x1+x2 dependence of invariant structure functions of (ππ)-pairs and compare them to single particle inclusive distributions in the fragmentation regions. Distributions of particles observed at Feynmanx2 in association with various “trigger” particles or systems atx1 in the same hemisphere are dicussed in terms of the reduced variable\(\tilde x_2= x_2 /(1 - |x_1 |)\). We further present absolute production rates and production ratios of π+'s and π−'s associated with π±,Ks0, Λ,\(\bar \Lambda \),K*+ (890), (Ks0π+), and (π+ π−)-triggers, and compare them with qualitative predictions of the quark recombination model. Forwardbackward correlations between (Ks0π±), (Ks0,p), (Λ, π−),\((\bar \Lambda \pi ^ \pm)\), and (p, π−) pairs are also discussed.

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Absolute inclusive cross sections for\(\bar pp\) interactions at 7.3 GeV/c are given. The data cover prong cross sections,V0, γ production and inclusive charged particle (p/π) production. Separation has been made into annihilation and non-annihilation components. Inclusive π+, π− production in the processes of\(\bar pp\) annihilation and non-annihilation are compared with simple quark models.

Inclusive K0K¯0, Λ0, and Λ¯0 cross sections have been determined using a 292-event/mb exposure of the hydrogen-filled 15-foot bubble chamber at Fermilab. From the invariant-mass distributions of V0π± pairs we find that σ(K*±(890))=4.4±1.4 mb, σ(Σ*±(1385))=0.54±0.40 mb, and σ(Σ¯*±(1385))=0.45±0.34 mb. It is estimated that 0.32 ± 0.11 of K0K¯0's, 0.21 ± 0.16 of Λ's, and 0.96 ± 0.75 of Λ¯'s originate from decays of K*(890) and Σ*(1385), respectively.

Results from a high-statistics experiment involving an exposure of the SLAC 82-in. hydrogen bubble chamber to a beam of 8-GeV/c π− yielding a final state of π−π+π−p are presented. Copious production of ρ, Δ++, and f is found. Considerable quasi-two-body production in which one particle decays to one of the above resonances is also observed. Some double-resonance production involving baryon and meson resonances is also seen. The production properties of ρ, Δ++, and f mesons are well described by a double-Regge model.

We have examined the inclusive production of nonstrange particle resonances in νp interactions using the Fermilab 15-ft bubble chamber. A sample of 2437 charged-current events with visible longitudinal momentum greater than 10 GeV/c was obtained. The ρ0 and Δ++(1232) are seen. An overall rate of 0.21±0.04 ρ0 per event is found. For five-prong events, the rate is 0.44±0.08 ρ0 per event. The ρ0Z distribution falls rapidly for Z greater than 0.4. The production of Δ++ is seen clearly in events with an identified proton. No evidence is seen for Δ0 production. An upper limit of 0.34 is placed on the ratio of ηπ0 (90% confidence level).

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Energy, charge and strangeness flow inK+p interactions at 32 and 70 GeV/c, and π+p interactions at 32 GeV/c are studied in terms of the angular variable λ=|x|/pT. The data ondQ/dλ anddE/dλ show only a weak indication of scale breaking between 32 and 70 GeV/c. For inclusive “non-diffractive”, inclusive “diffractive” and exclusive “non-diffractive” jets, the fraction of charge in any angular region ΔΩ away from the central region is found to be proportional to the energy fraction in the same interval. The data ondQ/dE versus λ are compatible with some versions of dual-sheet models and agree also with the LUND Monte-Carlo model. The data are also compared with\(v(\bar v)p\) interactions in BEBC. In exclusive channels the average ratiodQ/dS=0.78±0.04 is consistent, in the framework of fragmentation models, with a larger probability for the fragmentation of the\(\bar s\)-valence quark than theu-valence quark in theK+-meson.

An experiment using the Fermilab Single Arm Spectrometer (SAS) facility and an associated nonmagnetic vertex detector studied the reactions a+p→c+X, where a and c were π±, K±, p, or p¯. Extensive measurements were made at 100 and 175 GeV/c beam momenta with the outgoing hadrons detected in the SAS covering a kinematic range 0.12<x<1.0 and pT<1.25 GeV/c. Additional data covering a more restricted range in x were also gathered at 70 GeV/c incident momentum. In this high-statistics experiment, the identification of both the incoming and outgoing charged hadrons were made with a total of eight Čerenkov counters. New and extensive single-particle inclusive data for charged-particle production in low-pT hadronic fragmentation are presented. The average associated charged-particle multiplicity and pseudorapidity distributions are also given.

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We have measured the inclusive cross section for η production in e+e− interactions near charm threshold using the Crystal Ball detector. No pronounced structure in the energy dependence is observed. By comparing cross sections above and below charm threshold we obtain the limits (90% confidence limit): R(e+e−→FF¯X)RB(F→ηx)<0.15−0.32 (for Ec.m. from 4.0 to 4.5 GeV), RB(D→ηx)<0.13. Our results are inconsistent with a previous report of a large energy dependence of the η cross section ascribed to the crossing of the FF* and F*F* production thresholds.

The twofold differential cross section for the inelastic scattering of electrons on protons wa was measured as a function of the scattered electron energy for an electron scattering angle of 12°. The kinematic region covered in this experiment was 0.3 (GeV/ c ) 2 < q 2 < 1.0 (GeV/ c ) 2 and W < 2.9 GeV. The Bloom-Gilman as well as the constant scattering angle sum rule of Rittenberg and Rubinstein were tested.

We present the general properties of jets produced bye+e− annihilation. Their production and fragmentation characteristics have been studied with charged particles for c.m. energies between 12 and 43 GeV. In this energy rangee+e− annihilation into hadrons is dominated by pair production of the five quarksu, d, s, c andb. In addition, hard gluon bremsstrahlung effects which are invisible at low energies become prominent at the high energies. The observed multiplicity distributions deviate from a Poisson distribution. The multiplicity distributions for the overall event as well as for each event hemisphere satisfy KNO scaling to within ∼20%. The distributions ofxp=2p/W are presented; scale breaking is observed at the level of 25%. The quantityxpdδ/dxp is compared with multigluon emission calculations which predict a Gaussian distribution in terms of ln(1/x). The observed energy dependence of the maximum of the distributions is in qualitative agreement with the calculations. Particle production is analysed with respect to the jet axis and longitudinal and transverse momentum spectra are presented. The angular distribution of the jet axis strongly supports the idea of predominant spin 1/2 quark pair production. The particle distributions with respect to the event plane show clearly the growing importance of planar events with increasing c.m. energies. They also exclude the presence of heavy quark production,e+e−→Q\(\bar Q\) for quark masses up to 5<mQ<20.3 GeV (|eQ|=2/3) and 7<mQ<19 GeV (|eQ|=1/3). The comparison of 1/σtotdδ/dpT measured at 14, 22 and 34 GeV suggests that hard gluon bremsstrahlung contributes mainly to transverse momenta larger than 0.5 GeV/c. The rapidity distribution forW≧22 GeV shows an enhancement away fromy=0 which corresponds to an increase in yield of 10–15% compared to the centre region (y=0). The enhancement probably results from heavy quark production and gluon bremsstrahlung. The particle flux around the jet axis shows with increasing c.m. energy a rapidly growing number of particles collimated around the jet axis, while at large angles to the jet axis almost noW dependence is observed. For fixed longitudinal momentump‖ approximate “fan invariance” is seen: The shape of the angular distribution around the jet axis is almost independent ofW. The collimation depends strongly onp‖. For smallp‖,p‖<0.2 GeV/c, isotropy is observed. With increasingp‖ the particles tend to be emitted closer and closer to the jet axis.