Gell-Mann and Zweig recognized that their idea had a severe problem: one has to assign fractional charges to the quarks to come up with the known charges of the mesons and baryons.

• 格曼和瑞格认识到了他们的观点有些问题。问题之一就是必须为夸克分配部分电荷来解释介子和重子的电荷问题。