Point defects in IBS coating for very low loss mirrors.

High-reflective coatings are used in many physics experiments. Despite the high quality of the optical coating, the performances of the mirrors are altered by the scattered light induced by micrometer size defects in the coating layers. The topic of this paper is the study of the point-like scatterers present in the specific coating of the mirrors used in state-of-the-art, high-sensitivity optical experiments.

Lepton flavour violating top decays at the LHC.

We consider lepton-flavour violating decays of the top quark, mediated by 4-fermion operators. We compile constraints on a complete set of SU(3) [Formula: see text] U(1)-invariant operators, arising from their loop contributions to rare decays and from HERA's single-top search. The bounds on -[Formula: see text] flavour change are more restrictive than on [Formula: see text]-[Formula: see text]; nonetheless the top could decay to a jet [Formula: see text] with a branching ratio of order [Formula: see text].