Symmetric Mass Generation with Four SU(2) Doublet Fermions

Journal Article · 23 January 2025 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.134.031602 · OSTI ID:2506857

Butt, Nouman; Catterall, Simon ; Hasenfratz, Anna

We study a single exactly massless staggered fermion in the fundamental representation of an SU(2) gauge group. We utilize an nHYP-smeared fermion action supplemented with additional heavy Pauli-Villars fields that serve to decrease lattice artifacts. The phase diagram exhibits a clear two-phase structure with a conformal phase at weak coupling and a novel new phase, the symmetric mass generation (SMG) phase, appearing at strong coupling. The SMG phase is confining with all states gapped and chiral symmetry unbroken. Our finite size scaling analysis provides strong evidence that the phase transition between these two phases is continuous, which would allow for the existence of a continuum SMG phase. Furthermore, the renormalization group flows are consistent with a $\beta$ function that vanishes quadratically at the new fixed point, suggesting that the $N_f=4$ flavor SU(2) gauge theory lies at the opening of the conformal window. Published by the American Physical Society 2025

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0010005; SC0009998
• OSTI ID: 2506857
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 3 Vol. 134; ISSN 0031-9007; ISSN PRLTAO
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English