Roles of U ( 1 ) axial anomaly effects in cold and dense two-color QCD with 2 + 2 flavors
Year: 2025
Type: article
Abstract: We explore phase structures and hadron mass spectra in cold and dense two-color quantum chromodynamics (QCD) with 2 + 2 flavors where the sign problem disappears. We particularly focus on U ( 1 ) axial anomaly effects. We employ an N f = 2 + 2 linear sigma model based on the S U ( 8 ) Pauli-Gürsey symmetry to describe negative-parity as well as positive-parity hadrons, for which low-energy excitations are appropriately described particularly in the baryon superfluid phase with light diquark condensates. As a result, the strange chiral condensate is found to be enhanced in the superfluid phase owing to the flavor-mixing structure of U ( 1 ) axial anomaly effects. We also confirm this enhancement by means of the Nambu–Jona-Lasinio model. Besides, our present analysis predicts the existence of a novel superfluid phase where heavy diquarks condense in dense regime. The topological susceptibility with 2 + 2 flavors from the viewpoints of the anomaly effects and chiral-symmetry restoration is investigated. Furthermore, we derive a complete inverse mass hierarchy for negative-parity diquarks with sufficient anomaly effects. Our findings are expected to provide future lattice simulations with useful information on flavor-symmetry violation from the U ( 1 ) axial anomaly aspects in cold and dense two-color QCD medium.
DOI: 10.1103/mxq2-25x1
Authors: Manato Sakai, Daiki Suenaga
Institutions: Nagoya University, The University of Osaka
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4417212646