Co Raymond T, Harigaya Keisuke, Nomura Yasunori
Department of Physics, University of California, Berkeley, California 94720, USA and Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2017 Mar 10;118(10):101801. doi: 10.1103/PhysRevLett.118.101801. Epub 2017 Mar 7.
We present a simple and natural dark sector model in which dark matter particles arise as composite states of hidden strong dynamics and their stability is ensured by accidental symmetries. The model has only a few free parameters. In particular, the gauge symmetry of the model forbids the masses of dark quarks, and the confinement scale of the dynamics provides the unique mass scale of the model. The gauge group contains an Abelian symmetry U(1){D}, which couples the dark and standard model sectors through kinetic mixing. This model, despite its simple structure, has rich and distinctive phenomenology. In the case where the dark pion becomes massive due to U(1){D} quantum corrections, direct and indirect detection experiments can probe thermal relic dark matter which is generically a mixture of the dark pion and the dark baryon, and the Large Hadron Collider can discover the U(1){D} gauge boson. Alternatively, if the dark pion stays light due to a specific U(1){D} charge assignment of the dark quarks, then the dark pion constitutes dark radiation. The signal of this radiation is highly correlated with that of dark baryons in dark matter direct detection.
我们提出了一个简单自然的暗物质模型，其中暗物质粒子作为隐藏强动力学的复合态出现，并且它们的稳定性由偶然对称性保证。该模型只有几个自由参数。特别地，模型的规范对称性禁止暗夸克的质量，动力学的禁闭尺度提供了模型唯一的质量尺度。规范群包含一个阿贝尔对称性U(1)_D，它通过动能混合将暗物质部分和标准模型部分耦合起来。这个模型尽管结构简单，却具有丰富且独特的现象学。在暗π介子由于U(1)_D量子修正而获得质量的情况下，直接和间接探测实验可以探测热遗迹暗物质，它通常是暗π介子和暗重子的混合态，大型强子对撞机可以发现U(1)_D规范玻色子。或者，如果由于暗夸克特定的U(1)_D电荷分配使得暗π介子保持轻质量，那么暗π介子就构成暗辐射。这种辐射信号在暗物质直接探测中与暗重子的信号高度相关。
