Unitarity violation

Ufuk Aydemir, Mohamed Anber and I have just put out a paper that shows that the traditional signal for new physics – the violation of unitarity at tree level – is actually unconnected to the onset of the new degrees of freedom. Moreover, in the chiral theory it is even very far from being an upper bound, because tree-unitarity violation happens almost an order of magnitude before the QCD degrees of freedom are manifest. We also have a very interesting gravitational example.