Events are analyzed in which a high transverse momentum proton was produced at polar angles of 10°, 20° and 45°. The experiment was performed with the Split Field Magnet detector at the CERN ISR at\(\sqrt s \)=62 GeV. A 4-jet structure of these events is found [1]. The measured charge structure of spectator jets is compatible with proton production from hard diquark scattering. This is supported by a study of baryon number compensation in the towards jets. The observed charge compensation in the towards jets suggests dominance of hard (ud) scattering. Evidence forΔ++ production at high transverse momentum indicates the presence of an additional (uu) scattering component. The properties of the recoiling away jets are compatible with the fragmentation of a valence quark and/or of a gluon as in the case of meson triggers.
No description provided.
No description provided.
Ratios of inclusive cross sections σ(π+)/σ(π++K++p) and\(\sigma (\pi ^ -)/\sigma (\pi ^ -+ K^ -+ \bar p)\) were measured for proton-proton interactions with a highpT hadron in the final state around c.m.s. scattering angles θ≅20°, 20° and 45° at two ISR energies\(\sqrt s= 31\) Gev and 62 GeV. Results are shown as functions of transverse and longitudinal momentum and are compared with parton model predictions. The different dependences of positive and negative pion fractions atpT≅2–3 GeV/c on longitudinal momenta is similar to that observed in soft hadronic interactions at low values ofpT where the leading proton effect (diquark fragmentation) is known to contribute. The quantitative agreement of the data with diquark model predictions indicates the presence of diquark fragmentation also in highpT jets.
No description provided.
No description provided.
No description provided.
The ratios of high p T charged kaon to pion production cross sections at √ s = 45 and 62 GeV are presented. The values of the K ± π ± ratios are essentially independent of both √ s and x T = 2p T √s and are compatible with a strangeness suppression factor λ = 0.55. By contrast, the K − π − values fall with x T suggesting a gluonic origin of K − . QCD calculations agrees with the measurements.
No description provided.
No description provided.
We present results on inclusive study of particle production ratios in 405-GeV/c pp interactions from a Fermilab experiment using the 30-in. hydrogen bubble chamber. Single- and double-pion ratios π+π−, π+π−π−π−, and π+π−π+π+ as a function of the Feynman variable x are presented. From these analyses, it is shown that the quark-recombination picture seems to work well for particle production in the fragmentation region. The data on π+π− ratios in association with a leading π± or Λ are compared with each other and also with the π+π−π−π− ratio. These results further support a prediction of the quark-recombination model.
No description provided.
No description provided.
We present new data on charged particle production in p p interactions at 100 GeV/ c . Comparisons are made between p p annihilations (estimated by differences) between corresponding p p and pp data samples) and e + e − annihilation into hadrons. A technique for separating the inclusive proton and pion spectra is described and the resulting pion spectra are studied in terms of Feynman x , rapidity and p T . Comparison with pp data allows us to estimate the pion spectra in p p annihilations and we find agreement with predictions of Mueller-Regge theory. We also present results on semi-inclusive π ± and proton production, give updated topological cross sections and describe further attempts to isolate effects due to annihilations. Finally we investigate the diffractive excitation of the antiproton into low-mass states by studying events with a slow recoil proton.
No description provided.
No description provided.
No description provided.
A charge hyperon beam has been brought into operation at the CERN SPS. Particles are identified by a DISC Čerenkov counter, and decay products are analysed by a magnetic spectrometer. Cross sections for the inclusive production of π + , K + , p , Σ + , Σ − , ζ − , d, and π − , K − , p , Σ + , Σ − , ζ − , ω − , d in the forward direction have been measured at laboratory momenta between 70 and 130 GeV/ c . This range of momenta corresponds to 0.35 ⩽ x ⩽ 0.66 for an incident proton momentum of 200 GeV/ c . Antihyperon ( Σ − , ζ − , Σ + ) and Σ + and ω − fluxes have been measured for the first time in a hyperon beam.
No description provided.
No description provided.
No description provided.