标题： 夸克孤子作为强子的组成成分 显示英文标题

标题： Quark solitons as constituents of hadrons

摘要： 我们展示了二维多味QCD的静态解，这些解具有重子和介子的量子数，由夸克和反夸克孤子构成。 在孤立情况下，这些孤子具有无限能量，对应于一根携带非单态色通量的弦延伸到空间无穷远处。 当结合$N_c$种此类孤子时，会形成一个静态、有限能量、色单态的解，对应于一个重子。 同样，静态介子解由不同味的孤子和反孤子构成。 由于味守恒，介子对抗湮灭是稳定的。 静态解只有当玻色化拉格朗日量的基本场属于$U(N_c{\times}N_f)$而不是$SU(N_c) \times U(N_f)$时才存在。 讨论味对称性破缺需要仔细处理正规序歧义。 我们的结果可以看作是在QCD$_2$中对组成夸克模型的推导，允许对组成质量生成和重夸克对称性的详细研究。 显示英文摘要

摘要： We exhibit static solutions of multi-flavour QCD in two dimensions that have the quantum numbers of baryons and mesons, constructed out of quark and anti-quark solitons. In isolation the latter solitons have infinite energy, corresponding to the presence of a string carrying the non-singlet colour flux off to spatial infinity. When $N_c$ solitons of this type are combined, a static, finite-energy, colour singlet solution is formed, corresponding to a baryon. Similarly, static meson solutions are formed out of a soliton and an anti-soliton of different flavours. The stability of the mesons against annihilation is ensured by flavour conservation. The static solutions exist only when the fundamental fields of the bosonized Lagrangian belong to $U(N_c{\times}N_f)$ rather than to $SU(N_c) \times U(N_f)$. Discussion of flavour symmetry breaking requires a careful treatment of the normal ordering ambiguity. Our results can be viewed as a derivation of the constituent quark model in QCD$_2$, allowing a detailed study of constituent mass generation and of the heavy quark symmetry.