A Possible Detection of the Cosmic Antineutrino Background in the Presence of Flavor Effects

致密中微子环境中的集体中微子-反中微子振荡？

Collective neutrino-antineutrino oscillations in dense neutrino environments?

本文探讨了致密环境中集体中微子-反中微子振荡的可能性，指出后向散射受螺旋度抑制且对无质量中微子消失，非零质量下的集体螺旋度振荡虽在Majorana情形下等效于中微子-反中微子振荡，但受中微子微小质量抑制。

Neutrinos as Hot or Warm Dark Matter

Both active and sterile sub-eV neutrinos can serve for hot dark matter (DM). On the other hand, keV sterile neutrinos could be a good candidate for warm DM. The beta-decaying (e.g., H-3 and Ru-106) and EC-decaying (e.g., Ho-163) nuclei are considered as the most promising targets to capture those extremely low energy neutrinos and antineutrinos, respectively. We calculate the capture rates of relic electron neutrinos and antineutrinos against the corresponding beta-decay or EC-decay backgrounds in different flavor mixing schemes. We stress that such direct laboratory measurements of hot or war…

利用宇宙弦引力波探测轻子生成的味区

Probing flavored regimes of leptogenesis with gravitational waves from cosmic strings

本文首次提出利用宇宙弦辐射引力波的谱特征检验高尺度轻子生成的不同味区，前提是右手中微子质量标量场与希格斯弱耦合，还构建了无需约束味结构即可检验味区差异的框架并给出未来可检验的引力波窗口。

Cosmic Neutrino Flavor Ratios with Broken $ν_μ-ν_τ$ Symmetry

Reactor neutrino experiments have now observed a nonzero value for $θ_{13}$ at $5σ$, and global fits to data imply a nonzero value above $10σ$. Nonzero values for $θ_{13}$ and/or $θ_{32}-π/4$ break a $ν_μ-ν_τ$ symmetry, which has qualitative as well as quantitative implications for the time-evolution of neutrino flavors. In particular, the large-distance flavor evolution matrix, non-invertible with $ν_μ-ν_τ$ symmetry, is now invertible. This means that measurements of neutrino flavor ratios at Earth can now be inverted to directly reveal the flavor ratios injected at cosmically distant sources…

Relic Right-handed Dirac Neutrinos and Implications for Detection of Cosmic Neutrino Background

It remains to be determined experimentally if massive neutrinos are Majorana or Dirac particles. In this connection, it has been recently suggested that the detection of cosmic neutrino background of left-handed neutrinos $ν^{}_{\rm L}$ and right-handed antineutrinos $\overlineν^{}_{\rm R}$ in future experiments of neutrino capture on beta-decaying nuclei (e.g., $ν^{}_e + {^3{\rm H}} \to {^3}{\rm He} + e^-$ for the PTOLEMY experiment) is likely to distinguish between Majorana and Dirac neutrinos, since the capture rate is twice larger in the former case. In this paper, we investigate the possi…

从轻子味不对称性得到的宇宙重子化学势上限

Upper Bound on the Cosmic Baryon Chemical Potential from Lepton-Flavor Asymmetry

研究了轻子味不对称情形下QCD相变附近的早期宇宙轨迹，得到重子化学势上限，发现仅极端轻子味不对称无法达到一阶相变区域，将QCD时代遗迹限制在chiral crossover相变标准图景。