In the framework of seesaw neutrino masses from heavy fermion triplets $({\mathrm{\Sigma }}^{+},{\mathrm{\Sigma }}^0,{\mathrm{\Sigma }}^{-})$, the addition of a light fermion singlet N and a heavy scalar triplet $({\rho }^{+},{\rho }^0,{\rho }^{-})$ has some important consequences. The new particles are assumed to be odd under a new $Z_2$ symmetry which is only broken softly, both explicitly and spontaneously. With $N-{\mathrm{\Sigma }}^0$ mixing, freeze-in long-lived dark matter through Higgs decay becomes possible. At the same time, the W mass is shifted slightly upward, as suggested by a recent precision measurement.

中文翻译：

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III 型中微子跷跷板、冻结长寿命暗物质和 W 质量转移

在来自重费米子三重态的跷跷板中微子质量框架中$({\mathrm{\Sigma }}^{+},{\mathrm{\Sigma }}^0,{\mathrm{\Sigma }}^{-})$, 添加一个轻费米子单重态N和一个重标量三重态$({\rho }^{+},{\rho }^0,{\rho }^{-})$有一些重要的后果。假设新粒子在新粒子下是奇数$Z_2$对称性只是轻轻地被打破，无论是明确的还是自发的。和$ñ-{\mathrm{\Sigma }}^0$通过希格斯衰变混合、冻结长寿命的暗物质成为可能。同时，正如最近的精密测量所表明的那样， W质量略微向上移动。