Z' search in e $^+$ e $^-$ annihilation

hep-ph/9607306 Z ′ Search in e + e − Annihilation

Search for Photinos in E+e-annihilation *

We discuss the pair production of massive photinos +or other neutral gauginos in e e annihilation. We present +cross sections for e e ++ yy and e e -t yyy including finite mass effects for both the selectron and the gaugino. Experimental signatures are a possible pair of photons from T decay each with = l/4 Ec m and a single soft photon . . in the case of radiative pair production. We exhi...

Measurements of Z-boson resonance parameters in e+e- annihilation.

We have measured the mass of the 2 boson to be 91.14f0.12 GeV/c2, and its width to be 2.42ti.f: GeV. If we constrain the visible width to its Standard Model value, we find the partial width to invisible decay modes to be 0.46 f 0.10 GeV, corresponding to 2.8 3~0.6 neutrino species, with a 95% confidence level upper limit of 3.9. c W e present an improved measurement of the 2 boson resonance par...

Search for monojet production in e+e- annihilation.

A search for monojet production in e+cannihilation has been performed at fi = 29 GeV with the MAC detector at PEP. No events beyond those expected from tau decays have been found. The result has been interpreted as an upper _ s, limitfor Z” -decays into monojets, giving an upper limit for the branching ratio of 0.5% at the 90% confidence level. This limit excludes an interpretation that the mon...

Four-Fermi operators in e+e- annihilation experiments and uncertainties in Z boson properties.

We investigate the effects of possible new four-Fermi operators on e+ e− annihilation experiments. They represent a class of new physics, which has the potential to change the parameters of the Z boson and at the same time interferes with their determination from the data. We show that in the presence of such operators the Z parameters obtained from lineshape fits can change significantly. Anot...