Francis A, Hudspith R J, Lewis R, Maltman K
Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada.
Department of Mathematics and Statistics, York University, Toronto, Ontario M3J 1P3, Canada.
Phys Rev Lett. 2017 Apr 7;118(14):142001. doi: 10.1103/PhysRevLett.118.142001. Epub 2017 Apr 5.
We investigate the possibility of qq^{'}b[over ¯]b[over ¯] tetraquark bound states using n_{f}=2+1 lattice QCD ensembles with pion masses ≃164, 299, and 415 MeV. Motivated by observations from heavy baryon phenomenology, we consider two lattice interpolating operators, both of which are expected to couple efficiently to tetraquark states: one with a diquark-antidiquark and one with a meson-meson structure. Using nonrelativistic QCD to simulate the bottom quarks, we study the udb[over ¯]b[over ¯], ℓsb[over ¯]b[over ¯] channels with ℓ=u, d, and find unambiguous signals for strong-interaction-stable J^{P}=1^{+} tetraquarks. These states are found to lie 189(10) and 98(7) MeV below the corresponding free two-meson thresholds.
我们使用具有约164、299和415 MeV 介子质量的 (n_f = 2 + 1) 格点量子色动力学系综，研究 (qq^{'}b\overline{b}) 四夸克束缚态的可能性。受重子现象学观测结果的启发，我们考虑两个格点内插算符，预计它们都能有效地与四夸克态耦合：一个具有双夸克 - 反双夸克结构，另一个具有介子 - 介子结构。使用非相对论量子色动力学来模拟底夸克，我们研究了 (ud\overline{b}\overline{b})、(\ell s\overline{b}\overline{b}) 通道（其中 (\ell = u, d)），并发现了强相互作用稳定的 (J^{P}=1^{+}) 四夸克的明确信号。发现这些态位于相应的自由双介子阈值以下189(10) 和98(7) MeV 处。
