# Nonperturbative investigations of SU(3) gauge theory with eight dynamical flavors

Thomas Appelquist,
Richard C. Brower,
George T. Fleming,
Andrew Gasbarro,
Anna Hasenfratz,
Xiao-Yong Jin,
Ethan T. Neil,
James C. Osborn,
Claudio Rebbi,
Enrico Rinaldi,
David Schaich,
Pavlos Vranas,
Evan Weinberg,
Oliver Witzel

Jul 2018

### Abstract

We present our lattice studies of SU(3) gauge theory with $N_f$ = 8 degenerate fermions in the fundamental representation. Using nHYP-smeared staggered fermions we study finite-temperature transitions on lattice volumes as large as $L^3 \times N_t = 48^3 \times 24$, and the zero-temperature composite spectrum on lattice volumes up to $64^3 \times 128$. The spectrum indirectly indicates spontaneous chiral symmetry breaking, but finite-temperature transitions with fixed $N_t \leq 24$ enter a strongly coupled lattice phase as the fermion mass decreases, which prevents a direct confirmation of spontaneous chiral symmetry breaking in the chiral limit. In addition to the connected spectrum we focus on the lightest flavor-singlet scalar particle. We find it to be degenerate with the pseudo-Goldstone states down to the lightest masses reached so far by non-perturbative lattice calculations. Using the same lattice approach, we study the behavior of the composite spectrum when the number of light fermions is changed from eight to four. A heavy flavor-singlet scalar in the 4-flavor theory affirms the contrast between QCD-like dynamics and the low-energy behavior of the 8-flavor theory.

Publication

*Physical Review D*

###### Research Scientist

My research interests include artificial intelligence and quantum computing applied to particle physics and quantum many-body systems.