Varying fundamental constants and particle physics
by
Rikard Enberg(U), Tanumoy Mandal(Uppsala University)
→
Europe/Stockholm
Å12167 (Ångström)
Å12167
Ångström
Description
Abstract:
We will discuss an idea that was at first motivated by the recently reported and later departed 750 GeV diphoton excess at the LHC. To explain this excess, we considered a model where the electromagnetic coupling is controlled by a scalar field that couples to photons. In ultraviolet complete theories such as string theory, this is a very natural idea, and there are no free parameters. All coupling constants are instead given by vacuum expectation values of scalar fields.
When constructing a low-energy effective theory such as the Standard Model, the fundamental constants should in principle be derived from such vacuum expectation values at a high scale, but there are many obstacles and difficulties involved in such a construction. In this talk, we instead consider the idea of couplings set by scalar fields in bottom-up constructions, where the low-energy theory is constructed at lower scales as an effective field theory.
When fundamental constants are set by scalar fields, they are constant at low enough energies, when the field is stuck at the bottom of the potential minimum. If the field gets excited the constants can change, and models of this kind are therefore models for varying coupling constants. In a previous paper [arXiv:1601.00624] we considered the LHC phenomenology of the scalar field that lets the electromagnetic coupling vary in this way and we are now extending the model with a the generalization where all three gauge couplings of the Standard Model gauge group as well as the Yukawa couplings of the fermions are controlled by scalar fields, and we will present some collider signatures of this model.
This talk is based on arXiv:1601.00624 by U. Danielsson, R. Enberg, G. Ingelman and T. Mandal; arXiv:1612.01192 by T. Mandal; and work in progress.
