D.A. Troster

Proton-antiproton annihilations at rest into π0ω, π0η, π0γ, π0π0, and π0η′☆

Proton-antiproton annihilations at rest in liquid hydrogen were investigated through the inclusive γ spectrum, related to the annihilation. The high-energy part of the spectrum was used to deduce branching ratios for the so far unobserved annihilation channels: R(pp→π0ω) = (2.38 ± 0.65)%, R(pp→ π0η) = (0.82 ± 0.10%, Rpp→π0γ) = (0.015 ± 0.007)%, and R(pp → π0π0 = (0.06 ± 0.04)%. An upper limit for the π0η′ channel was deduced to be R(pp → π0η′) < 1.1%.

New results in the search for narrow states in the p system below threshold

The γ-ray spectrum after p annihilation at rest was measured in two independent high-statistics runs. Both spectra show narrow peaks, corresponding to masses of 1210, 1638, 1694 and 1771 MeV.

Trigger using track search and kinematical analysis for rare decay channels at high rates

Abstract We report on the definition and construction of the trigger system for the CP violation experiment with tagged K 0 (PS195) at LEAR, the low energy antiproton machine at CERN. The beam is assumed to have a continuous intensity of 2 × 10 6 antiprotons per second. The requirements for fast and efficient rejection are stringent.

A π0 and η spectrometer of lead glass and BGO for momenta up to 1 GeV/c

Abstract A spectrometer consisting of two sets of bismuth germanium oxide (BGO) crystals and a lead-glass array has been used to measure the π 0 and η momentum spectra produced from proton-antiproton annihilations at rest. We describe the test of the BGO sets in electron beams of energies from 50 to 450 MeV. We discuss the method of construction and calibration of the lead-glass array, as well as procedures to extract the energy and position resolutions for detected photons. A momentum resolution (σ) for π 0 s and ηs of 4% and 3%, respectively has been achieved at momenta below 1 GeV/ c .

Experimental determination of the branching ratios\(p\bar p \to 2\pi ^0 ,\pi ^0 \gamma \), and 2γ at rest

AbstractThe branching ratios of

Experimental determination of the branching ratios {Mathematical expression}, and 2γ at rest

p\bar p

π0 and η spectra from\(p\bar p\) annihilations at rest

annihilations into the neutral final states 2π0, π0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are