Twisted Poincar\'e Symmetry and Some Implications on Noncommutative Quantum Field Theory

The concept of twisted Poincar\'e symmetry, as well as some implications, are reviewed. The spin-statistics relation and the nonlocality of NC QFT are discussed in the light of this quantum symmetry. The possibility of a twisted symmetry principle for quantum field and gauge theories formulated on a noncommutative space-time is also explored.Comment: Talk given at the 21st Nishinomiya-Yukawa Memorial Symposium on Theoretical Physics "Noncommutative Geometry and Quantum Space-Time in Physics", Nishinomiya-Kyoto, Japan, 11-15 November 200

On neutrino masses via CPT violating Higgs interaction in the Standard Model

The Lorentz invariant $CPT$ violation by using non-local interactions is naturally incorporated in the Higgs coupling to neutrinos in the Standard Model, without spoiling the basic $SU(2)_{L}\times U(1)$ gauge symmetry. The neutrino--antineutrino mass splitting is thus realized by the mechanism which was proposed recently, assuming the neutrino masses to be predominantly Dirac-type in the Standard Model.Comment: 8 page