Standard Model Amplitudes Research Articles

Could large CP-violation be detected at colliders?

We argue that CP-violation effects below a few × 10−3 are probably undetectable at hadron and electron colliders. Thus only operators whose contributions interfere with tree-level Standard Model amplitudes are detectable. We list these operators for Standard Model external particles and some two- and three-body final state reactions that could show detectable effects. These could test electroweak baryogenesis scenarios.

Bounds on neutrino masses from neutrino decay rates, cosmology and the see-saw mechanism

We study the constraints imposed on the masses of ν e, ν μ and ν T on the basis of direct experimental bounds, cosmological bounds, theoretical calculations of neutrino decay rates, experimental bounds on related decay charged leptons and the structure of neutrino mass matrices in the “see-saw” mechanism. We consider standard model amplitudes as well as contributions from all “beyonds standard” models. Assuming a simple “reasonable” form of the see-saw mechanism, we derive the bounds: m( ν T ) ⩽ 65 eV, m( ν ggm ) ⩽ 4 eV, m( ν e) ⩽ 0.02eV, M(W R) ⩾ 50 PeV. Possible ways of evading these boundsare discussed.