标题： 一个来自扩大的色群的可见QCD轴子 显示英文标题

标题： A Visible QCD Axion from an Enlarged Color Group

摘要： 我们考虑了扩展的QCD色群SU(3+$N^\prime$)自发破缺到SU(3)$_c\times$SU($N^\prime$)的情况，并带有额外的矢量型夸克，这些夸克以基本表示形式变换。 当重夸克在PQ破缺尺度以下被积分掉时，它们生成了一个轴子耦合，这个耦合同时解决了两个规范群的强CP问题。 然而，轴子质量现在从SU($N^\prime$)禁闭尺度接收一个新的非微扰贡献，这可能比QCD尺度大得多。 这可以将轴子质量提高到电弱尺度或以上。 这种可见的轴子随后可以衰变为胶子和光子，在LHC的Run-II阶段产生可观察到的信号。 特别是，如果质量被识别为750 GeV双光子共振，则新的禁闭尺度为$\sim$TeV，而PQ破缺尺度为$\sim$10 TeV。 这预测了多TeV范围内的矢量型夸克和PQ标量共振，且暗物质可能是SU($N^\prime$)重子的可能性存在。 显示英文摘要

摘要： We consider the possibility of an enlarged QCD color group, SU(3+$N^\prime$) spontaneously broken to SU(3)$_c\times$SU($N^\prime$) with extra vector-like quarks transforming in the fundamental representation. When the heavy quarks are integrated out below the PQ-breaking scale, they generate an axion coupling which simultaneously solves the strong CP problem for both gauge groups. However, the axion mass now receives a new nonperturbative contribution from the SU($N^\prime$) confinement scale, which can be substantially larger than the QCD scale. This can increase the axion mass to be at or above the electroweak scale. This visible axion can then decay into gluons and photons giving rise to observable signals at Run-II of the LHC. In particular, if the mass is identified with the 750 GeV diphoton resonance then the new confinement scale is $\sim$ TeV and the PQ-breaking scale is $\sim$ 10 TeV. This predicts vector-like quarks and a PQ scalar resonance in the multi-TeV range, with the possibility that dark matter is an SU($N^\prime$) baryon.