Dror Jeff A, Hiramatsu Takashi, Kohri Kazunori, Murayama Hitoshi, White Graham
Department of Physics, University of California, Berkeley, California 94720, USA.
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2020 Jan 31;124(4):041804. doi: 10.1103/PhysRevLett.124.041804.
We present the possibility that the seesaw mechanism with thermal leptogenesis can be tested using the stochastic gravitational background. Achieving neutrino masses consistent with atmospheric and solar neutrino data, while avoiding nonperturbative couplings, requires right handed neutrinos lighter than the typical scale of grand unification. This scale separation suggests a symmetry protecting the right-handed neutrinos from getting a mass. Thermal leptogenesis would then require that such a symmetry be broken below the reheating temperature. We enumerate all such possible symmetries consistent with these minimal assumptions and their corresponding defects, finding that in many cases, gravitational waves from the network of cosmic strings should be detectable. Estimating the predicted gravitational wave background, we find that future space-borne missions could probe the entire range relevant for thermal leptogenesis.
我们提出了一种可能性，即可以利用随机引力背景来检验具有热轻子生成的跷跷板机制。要实现与大气中微子和太阳中微子数据一致的中微子质量，同时避免非微扰耦合，需要右手型中微子比大统一的典型尺度更轻。这种尺度分离表明存在一种对称性，可保护右手型中微子不获得质量。那么热轻子生成将要求这种对称性在再加热温度以下被打破。我们列举了所有与这些最小假设及其相应缺陷一致的可能对称性，发现许多情况下，宇宙弦网络产生的引力波应该是可探测的。通过估计预测的引力波背景，我们发现未来的太空任务可以探测与热轻子生成相关的整个范围。
