Field distortions from persistent currents in the superconducting HERA magnets

Measurements and calculations are presented on the sextupole and decapole components in the HERA dipole magnets and the 12-pole and 20-pole components in the quadrupoles. The data show a strong current dependence and a characteristic hysteresis behaviour. Good agreement is found with model calculations which are based on eddy currents in the niobium-titanium filaments of the superconducting cable

e+ e- ANNIHILATION AT HIGH-ENERGIES AND SEARCH FOR THE t-QUARK CONTINUUM CONTRIBUTION

Measurements of R , sphericity and thrust are presented for c.m. energies between 12 and 31.6 GeV. A possible contribution of a t continuum can be ruled out for c.m. energies between 16 and 31 GeV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47882/1/10052_2005_Article_BF01554391.pd

TWO PHOTON EXCITATION OF THE TENSOR MESON f0 (1270)

We have measured charged particle pair production in two-photon scattering at the e+e- storage ring PETRA. While the main source of such events is the production of lepton pairs, the presence of an additional process is clearly indicated by the measured invariant mass distribution of the two particles and their angular distributions. We determine that the excess is mainly due to the decay f0(1270)→π+π-. We derive a width Γ(f0→γγ)=3.2±0.2±0.6 keV (statistical and systematic). © 1981 Springer-Verlag