A dynamical gluon mass solution in a coupled system of the Schwinger-Dyson equations

We study numerically the Schwinger-Dyson equations for the coupled system of gluon and ghost propagators in the Landau gauge and in the case of pure gauge QCD. We show that a dynamical mass for the gluon propagator arises as a solution while the ghost propagator develops an enhanced behavior in the infrared regime of QCD. Simple analytical expressions are proposed for the propagators, and the mass dependency on the $\Lambda_{QCD}$ scale and its perturbative scaling are studied. We discuss the implications of our results for the infrared behavior of the coupling constant, which, according to fits for the propagators infrared behavior, seems to indicate that $\alpha_s (q^2) \to 0$ as $q^2 \to 0$.Comment: 17 pages, 7 figures - Revised version to be consistent with erratum to appear in JHE

Balance-of-Powers Arguments and the Structural Constitution

Balance-of-powers arguments are ubiquitous in judicial opinions and academic articles that address separation-of-powers disputes over the president\u27s removal authority, power to disregard statutes, authority to conduct foreign wars, and much else. However, the concept of the balance of powers has never received a satisfactory theoretical treatment. This Essay examines possible theories of the balance of powers and rejects them all as unworkable and normatively questionable. Judges and scholars should abandon the balance-of-powers metaphor and instead address directly whether bureaucratic innovation is likely to improve policy outcomes