标题： 手征对称性破缺与强子的自旋组成 显示英文标题

标题： Chiral symmetry breaking and the spin content of hadrons

摘要： 从无限动量框架中的部分子分布可以发现，只有大约30%的核子自旋是由价夸克的自旋携带的，这引发了“自旋危机”这一术语。 对于最低能级的介子，类似的结果也成立，这可以从格点模拟中得出。 我们在静止框架中定义介子的自旋组成，并使用一个完整正交的$\bar q q$色荷基矢，以及从色荷基矢到 (2S+1)LJ 基的幺正变换。 然后，给定在某一分辨率尺度下介子波函数中不同允许的色荷表示的混合，就可以得到该尺度下的自旋组成。 为了获得介子中色荷表示的混合，我们在动态格点模拟中测量了具有不同色荷结构的极化子耦合比值。 对于 rho 介子，我们得到的几乎是 3S1 状态，没有任何自旋危机的痕迹。 那么自然会提出一个问题：哪种定义能够反映强子的自旋组成？ 显示英文摘要

摘要： From the parton distributions in the infinite momentum frame one finds that only about 30% of the nucleon spin is carried by spins of the valence quarks, which gave rise to the term "spin crisis". Similar results hold for the lowest mesons, as it follows from the lattice simulations. We define the spin content of a meson in the rest frame and use a complete and orthogonal $\bar q q$ chiral basis and a unitary transformation from the chiral basis to the (2S+1)LJ basis. Then, given a mixture of different allowed chiral representations in the meson wave function at a given resolution scale, one can obtain its spin content at this scale. To obtain the mixture of the chiral representations in the meson we measure in dynamical lattice simulations a ratio of couplings of interpolarors with different chiral structure. For the rho meson we obtain practically the 3S1 state with no trace of the spin crisis. Then a natural question arises: which definition does reflect the spin content of a hadron?