H. Muirhead

A study of deep inelastic hadron-hadron collisions with a large acceptance calorimeter trigger

Abstract Large transverse energy cross sections of 300 GeV/ c pions and protons on hydrogen have been measured with a segmented calorimeter covering the central rapidity region −0.88 y π in azimuth. The selected events show large multiplicities and no jet-like event structure. Processes more complicated than the scattering of two constituents appear to dominate these inelastic collisions.

The reaction (π−, 2n) in 6Li and 7Li

Abstract We have examined the energy spectra and angular distributions of the two neutrons emitted following pion capture at rest in the isotopes of 6Li and 7Li. A time-of-light technique was used. Data are presented on the binding energies and total momenta of the neutrons in the parent nuclei. In approximately 40% of the pion captures the reactions lead to the ground states of the nuclei 4He and 5He from capture in 6Li and 7Li, respectively; the characteristic features involving the emission of a pair of neutrons differ considerably in the two isotopes.

Cross sections of annihilation and inelastic final states for pp interactions at 9.1 GeV/c

Abstract Topological and channel cross sections are given for annihilation and inelastic final states produced in p p interactions at 9.1 GeV/c. Cross sections for prominent resonances in specific channels and charged pion, ϱ 0 and Δ ++ inclusive cross sections are also presented.

Cross sections of common final states for K−p interactions at 8.25 GeV/c

Abstract Topological and channel cross sections are given for the more common final states produced in K − p interactions at 8.25 GeV/ c together with the single particle inclusive cross sections. We present cross sections for prominent resonances occurring in final states K N (nπ) and find the resonance fractions to be roughly independent of multiplicity.

General features of the pp interaction at 12 GeV/c

Simple inclusive cross sections for pp interactions at 12 GeV/c are given. The data cover prong cross sections, V0 production and resonances. Separation has been made into annihilation and non-annihilation modes. Some implications of the data are discussed. It is pointed out that the ratios of cross sections for ϱ0π− production are independent of incident antiproton momentum in pp annihilation processes, and that data at the highest available pp energies (ISR) tend to the same value.

Cross sections and multiplicity distributions for pp annihilations at 4.6 GeV/c

Channel cross sections have been determined for pp annihilations into final states containing 3 to 9 pions at 4.6 GeV/c. The moments of both the charged and neutral pion multiplicity distributions are presented and model predictions are critically examined.

A study of high transverse energy interactions of 150 and 300 GeV pions and protons on a hydrogen target using a large acceptance calorimeter

Interactions of 150 GeV pions and 300 GeV pions and protons on hydrogen which result in final states with large transverse energy in the central rapidity region −0.88 < y < 0.67 were studied with a calorimeter trigger. The dependence of the cross section on the azimuthal acceptance of the trigger, on the beam energy and on the incident particle type and the jet properties of the events were investigated. No dominant two-jet structure was found. Nevertheless, the parton spectrum in the colliding hadrons appears to be relevant for large transverse energy reactions.

NEUTRAL RADIATIONS FOLLOWING PION CAPTURE IN COMPLEX NUCLEI

Abstract A time-of-flight technique has been used to measure the energy spectra of neutrons emitted following pion capture in nuclei of widely varying atomic weight. The spectra are characterized by a low-energy “evaporation” part and a high-energy “direct” component. Nuclear temperatures have been calculated from the former. The apparatus also detected γ-radiation, and relative photon yields are given.

Gross features of the annihilation process pp → n π

Abstract The behaviour of the mean square of the matrix element for proton-antiproton annihilation to multipion systems has been examined with the aid of the experimental data. A simple dependence on the parameter s (the square of the energy in the c-system) is found which is independent of multiplicity.

Search for single cluster formation in annihilation reactions

Single-particle inclusive data from pp annihilation experiments at 4.6 and 9.2 GeV/c are displayed, and compared with other data from NN and e+e− annihilation reactions. The single-particle distributions are found to be exponentially peaked and almost isotropic at small momenta in the centre of mass. The temperature, or exponential slope of this distribution, is well fitted by a linear form in s−12, extrapolating to an “ultimate temperature” of 164 ± 5 MeV. These results are in accordance with the hypothesis that the annihilations very often give rise to the formation of single clusters, whose decay can be described by the statistical bootstrapmodel. Attempts to isolate a class of events corresponding to single cluster formation are discussed.