D.N. Edwards

Production of high transverse momentum prompt photons and neutral pions in proton-proton interactions at 280 GeV/c

The inclusive cross sections for production of prompt photons and π0s by 280 GeV/c protons incident on a liquid hydrogen target, have been measured forpT in the range 4.0 to 6.5 GeV/c and for |xF|<0.45. A quantitative comparison of the prompt photon cross section with next-to-leading order QCD predictions using Duke and Owens structure functions is performed. Phenomenological fits to the π0 and prompt photon cross sections are given.

The four-prong annihilation of 1.2 GeV/c antiprotons in hydrogen (II) π+π+π−π−π0 final state

Abstract Approximately 17 000 four-prong annihilations of 1.2 GeV/ c antiprotons in hydrogen have been analyzed. The present report considers those events with one neutral pion (5π). The 5π events show production of ϱ 0 , ϱ ± , f 0 , ω 0 , η 0 mesons, and the possibility of a ϱϱ enhancement at 1400 MeV/ c and/or a ϱπ enhancement at 1080 MeV/ c is considered. The influence of the Bose-Einstein correlation function of Goldhaber et al. [6] is investigated. Centre-of-mass angular distributions of the pions and centre-of-mass opening angles between pairs of pions are presented. The production upper limits at the 95% confidence level, for several resonant states are given.

High transverse momentum prompt photon production by π− and π+ on protons at 280 GeV/c

The inclusive cross sections for prompt photon production by π− and π+ on protons have been measured with a beam momentum of 280 GeV/c using a fine grained electromagnetic calorimeter and the CERN Omega spectrometer. The transverse momentum and FeynmanxF ranges covered are 4.0<pT<7.0GeV/c and −0.45<xF<0.55 respectively. A quantitative comparison of the prompt photon cross section with next-to-leading order QCD predictions using Duke and Owens structure functions is performed.

Evidence for a narrow width boson of mass 2.95 GeV

Abstract In a search for resonances coupled to the p pπ − system, we have studied π − p interactions at 16 GeV/ c giving a forward antiproton, using the Omega spectrometer at CERN. In the final states involving a p , p and π − we observe a 5.6 (6.3) standard deviation enhancement in the p pπ − mass spectrum at (2.95 ± 0.01) GeV with a width consistent with the resolution ( σ = 15 MeV). The production cross section × branching ratio is estimated to be of the order 1 μb. The data are consistent with a resonance decaying partly via intermediate p p final states.

The applicability of Zweig's rule to p̄p annihilations at 3.6 GeV/c

Abstract The final states oππ and oKK arising from pp annihilations at 3.6 GeV/ c have been studied. The results are in agreement with Zweigs rule contrary to what is observed in high energy pp collisions.

Antiproton-proton annihilation into (KK + 3π) and (KK + 4π) at 1.2 GeV/c study of the DO properties

Experimental results are presented for the five- and six-body annihilations pp → KK3π and pp → KK 4π of 1.2 GeV/c antiprotons. Analysis of these results in terms of production of K∗(890), ϱ, ω, η and D(1280) resonances is made. A detailed analysis of the quantum numbers for the D-meson is given.

Evidence for a new pseudoscalar meson

Abstract Performing a PWA of the π − π − π + system over the −t p/p range 0.2 to 0.4 GeV 2 we find evidence for a J P = 0 − , J G =1 − meson of mass 1342 ± 20 MeV and width 220 ±70 MeV decaying into ϵπ. This state is produced by natural parity exchange with a slope similar to that of elastic scattering. It can be interpreted as a radial excitation of the π meson (π′).

The reaction\bar pp \to \bar \Lambda \Lambda between 1.50 and 2.06 GeV/e

SummaryThe reaction

Analysis of KK and KKπ resonances produced in pp annihilations at 1.2 GeV/c

\bar pp \to \bar \Lambda \Lambda