Aachen 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

T: Fachverband Teilchenphysik

T 41: Theorie: Beyond the Standard Model

T 41.2: Talk

Tuesday, March 26, 2019, 16:15–16:30, S16

Gauge Coupling Unification without Supersymmetry — •Jakob Schwichtenberg — TTP Karlsruhe Institut für Technologie, Karlsruhe, Deutschland

We discuss the prospects to achieve unification of the gauge couplings in models without supersymmetry. We restrict our discussion to SU(5), SO(10) and E₆ models that mimic the structure of the Standard Model as much as possible ("conservative models"). One possible reason for the non-unification of the standard model gauge couplings are threshold corrections which are necessary when the masses of the superheavy fields are not exactly degenerate. We calculate the threshold corrections in conservative models with a Grand Desert between the electroweak and the unification scale. We argue that only in conservative E₆ models the corrections can be sufficiently large to explain the mismatch and, at the same time, yield a long-enough proton lifetime. A second possible reason for the mismatch are particles at an intermediate scale. We therefore also study systematically the impact of additional light scalars, gauge bosons and fermions on the running of the gauge coupling. We argue that for each of these possibilities there is a viable scenario with just one intermediate scale.