Observing Dirac neutrinos in the cosmic microwave background
Observing Dirac neutrinos in the cosmic microwave background
复制标题
DOI：
10.1103/physrevd.100.075027
复制
发表时间：
2019-08
影响因子：
5
通讯作者：
K. Abazajian;J. Heeck
中科院分区：
文献类型：
--
作者：
K. Abazajian;J. Heeck
计划中的CMB第四阶段实验有可能以百分比级别的精度测量早期宇宙中相对论自由度的有效数量。这探测了新的热化光粒子，也限制了狄拉克中微子可能的新物理相互作用。许多狄拉克-中微子模型旨在解决狄拉克稳定性，中微子质量的小或我们宇宙的物质-反物质不对称，赋予右手手性伙伴额外的相互作用，可以使它们热化。除非我们宇宙的再加热温度很低，否则这将导致可测试的偏差在$N_\text{eff}$。我们讨论了$\nu_R$相互作用的良好动机模型，如测量的$U(1)_{B-L}$和亲中微子的双希格斯双重态模型，并比较了SPT-3G、西蒙斯天文台和CMB-S4与其他实验的灵敏度，特别是与LHC的灵敏度。
Planned CMB Stage IV experiments have the potential to measure the effective number of relativistic degrees of freedom in the early Universe, $N_\text{eff}$, with percent-level accuracy. This probes new thermalized light particles and also constrains possible new-physics interactions of Dirac neutrinos. Many Dirac-neutrino models that aim to address the Dirac stability, the smallness of neutrino masses or the matter--anti-matter asymmetry of our Universe endow the right-handed chirality partners $\nu_R$ with additional interactions that can thermalize them. Unless the reheating temperature of our Universe was low, this leads to testable deviations in $N_\text{eff}$. We discuss well-motivated models for $\nu_R$ interactions such as gauged $U(1)_{B-L}$ and the neutrinophilic two-Higgs-doublet model, and compare the sensitivity of SPT-3G, Simons Observatory, and CMB-S4 to other experiments, in particular the LHC.