2010/09/09 by Toru T. Takahashi, Makoto Oka · 5 citations
Physics and Astronomy · #Baryon #Degenerate energy levels #High-Energy Particle Collisions Research #Lattice (music) #Lattice QCD #Lattice field theory #Particle physics theoretical and experimental studies #Pion #Quantum Chromodynamics and Particle Interactions #Quark #hep-lat
paper · pdf · doi:10.1143/ptps.186.172
published in Progress of Theoretical Physics Supplement 186, 172-179 (Oxford University Press) · Proceedings of a talk given at "New Frontiers in QCD 2010 (NFQCD10)", Kyoto, Japan, 18 January to 19 March, 2010
arxiv created 2010/09/09 · openalex publication_date 2010/10/01 · arxiv updated 2011/03/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Low-lying Λ baryons with spin 1/2 are analyzed in two-flavor lattice QCD. In order to extract two low-lying states for each parity, we construct 2 ×2 cross correlators from flavor SU(3) “octet” and “singlet” baryon operators, and diagonalize them. Two-flavor CP-PACS gauge configurations are employed, which are generated with the renormalization-group improved gauge action and the O(a)-improved quark action. Simulations are performed at three different β's, β= 1.80, 1.95 and 2.10, whose corresponding lattice spacings are a = 0.2150, 0.1555 and 0.1076 fm. For each cutoff, we adopt four different hopping parameters, (κ val, κ sea). The corresponding pion masses range from about 500 MeV to 1.1 GeV. The results are extrapolated to the physical quark-mass point. Our results indicate that there are two negative-parity Λ states nearly degenerate at around 1.6 GeV, whereas no state as low as Λ(1405) is observed. By extracting the flavor components of each state, we find that the lowest (1st-excited) negative-parity state is dominated by flavor-singlet (flavor-octet) component.