标题： 质子对撞机上的顶夸克以外的单态夸克？ 显示英文标题

标题： Singlet quarks beyond the top at the Tevatron?

摘要： 在费米实验室首次发现顶夸克的证据可能表明截面高于量子色动力学的预期。 我们考虑同位旋单态重夸克可能对信号有所贡献，并讨论检验这种可能性的方法。 例如，一个电荷为$\case2/3$的单态夸克，与顶夸克近似简并并发生混合，将有效使标准顶夸克信号翻倍。 一个电荷为$-\case1/3$的单态夸克与底夸克发生混合，不会影响顶夸克信号，但会生成带有$b$标记的$Z+{}$多喷注事件。 显示英文摘要

摘要： The first evidence for the top quark at the Tevatron may indicate a cross section higher than the QCD expectation. We consider the possibility that isosinglet heavy quarks may be contributing to the signal and discuss ways of testing this possibility. For example, a charge $\case2/3$ singlet quark, approximately degenerate and mixing with the top quark, would effectively double the standard top signals. A charge $-\case1/3$ singlet quark mixing with the bottom quark would not affect top signals but would generate excess $Z+{}$multijet events with a $b$-tag.