arXiv subjects
Publications and source records attributed to Andreas Stergiou.
We present an example of a limit cycle, i.e., a recurrent flow-line of the beta-function vector field, in a unitary four-dimensional gauge theory. We thus prove that beta functions of four-dimensional gauge theories do not produce gradient flows. The limit cycle is established in perturbation theory with a three-loop calculation which we describe in detail.
We explore phenomenological consequences of coupling a non-conformal scale-invariant theory to the standard model. We point out that, under certain circumstances, non-conformal scale-invariant theories have oscillating correlation functions which can dramatically modify standard model processes. We dub this scenario cyclic unparticle physics, or simply cyclunparticle physics. We compute phase spaces and amplitudes associated with final state cyclunparticle and cyclunparticle exchange, respectively. We show detailed formulae in a simple example.
We consider using broken superconformal symmetry and the super operator product expansion (sOPE) to constrain and analyze hidden sector theories that couple to our gauge forces and are not necessarily weakly coupled. Conformal and supersymmetry breaking are IR effects, associated with field or spurion expectation values, whereas the sOPE is determined in the UV and hence does not notice the breaking. The broken superconformal symmetry relates OPE coefficients of superconformal descendant operators to those of the superconformal primaries. We apply these ideas to the current correlators of general gauge mediation (GGM). We also consider analyticity properties of these correlators, e.g. their discontinuities, and use the optical theorem to relate them to total scattering cross sections from visible to hidden sector states, e.g. sigma(vis + vis --> hidden), analogous to sigma(e+ e- --> hadrons) in QCD. We discuss how the current-current OPE can be truncated to the first few terms to get a good approximation to the visible sector soft masses of GGM.
In this paper we study the orbits of massive bodies moving in the spacetime generated by a spherically symmetric and non-rotating distribution of mass. More specifically, our treatment discusses the more accurate calculation of the precession of pericenter due to general-relativistic effects. Our result is accurate up to terms of second order, while the precession met in the bibliography is accurate only up to first-order terms.