Speaker
Description
We investigate, for the first time, the Sp(4) lattice gauge theory in the presence of fermions at finite temperature, examining the theory with two dynamical Wilson fermions in the fundamental representation. The continuum theory is of interest as it provides a realisation of composite dark matter and may generate an observable stochastic gravitational wave signal, sourced by a phase transition in the early universe. Evaluating the sensitivity of future gravitational wave experiments to this signal requires knowledge of the strength of the phase transition. We explore the two dimensional parameter space of the theory, defined by the bare fermion mass and inverse gauge coupling. For this exploratory study we focus on lattices with small number of sites in the temporal dimension. We analyse the finite volume scaling behaviour of Polyakov loop observables, specifically the scaling of the peak of the susceptibility, informed by multi histogram reweighting, to discriminate between the presence of a phase transition or crossover. In the light fermion mass regime we find strong indications of a crossover, while in the regime of heavy fermion mass we find preliminary evidence of a first order phase transition. These findings motivate further studies of the continuum limit for this and other gauge groups in the Sp(2N) family.