Learn More
Antiproton-proton annihilation into 0 has been studied with the Crystal Barrel spectrometer at CERN at an incident beam momentum of 1.94 GeV/c. The data were taken with a trigger requiring neutral nal states. A new isovector state, the a2(1660) decaying to 0 , is observed. In the invariant mass region around 2.1 GeV=c 2 , strong production of a heavy(More)
  • A Abele, B Adomeit, +78 authors C Zupan
  • 2007
The annihilation channels pp!! 0 , !, ! 0 were studied with the Crystal Barrel detector at LEAR at p-momenta of 600, 1200, and 1940 MeV=c. In most cases angular distributions were measured which allowed a complete J P-analysis using the helicity formalism. The contribution of all relevant initial states could be determined. The maximal contributing angular(More)
Various electron cloud effects (ECE) including the two-stream (e-p) instability at the Los Alamos Proton Storage Ring (PSR) have been studied extensively for the past five years with the goal of understanding the phenomena, mitigating the instability and ultimately increasing beam intensity. The specialized diagnostics used in the studies are two types of(More)
A prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability has been developed and successfully tested at the Los Alamos Proton Storage Ring (PSR). The system was able to improve the instability threshold (as measured by the RF buncher voltage) by ~30%. This paper describes the feedback system(More)
The 0 momentum dependence of the decay ! + ? 0 has been measured with the Crystal Barrel detector. The analysis is based on 3230 events. The results of this independent measurement are compared to new chiral perturbation theory calculations and previous measurements. The calculation of the amplitude of the decay into three pions has been a longstanding(More)