Spectrum and Bethe-Salpeter amplitudes of ? baryons from lattice QCD

The ? baryons with J~P =3/2~±,1/2~± are studied on the lattice in the quenched approximation. Their mass levels are ordered as M_(3/2+) < M_(3/2-) ≈ M_(1/2-) < M_(1/2+), as is expected from the constituent quark model. The mass values are also close to those of the four ? states observed in experiments. We calculate the Bethe-Salpeter amplitudes of Q(3/2~+) and ?(1/2~+) and find there is a radial node for the ?(1/2~+) Bethe-Salpeter amplitude, which may imply that ?(1/2~+) is an orbital excitation of Q baryons as a member of the (D, L_N~P)= (70,0_2~+) supermultiplet in the SU(6)?O(3) quark model description. Our results are helpful for identifying the quantum numbers of experimentally observed ? states.Supported by National Science Foundation of China (NSFC),Youth Innovation Promotion Association of CAS, NSFC中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)4041001-01-041001-074