论文标题
从新的$ \ text {u}（1）_ \ text {b-l} $冻结辐射kev-cale中微子暗物质
Freeze-In of radiative keV-scale neutrino dark matter from a new $\text{U}(1)_\text{B-L}$
论文作者
论文摘要
我们扩展了Dirac Scotogenic模型，目的是通过相同的一环拓扑结构实现中微子质量以及KEV规模的暗物质（DM）候选者的质量。标准模型（SM）的两个中微子变成了巨大的狄拉克费米，而第三个中微子仍然无质量。我们的粒子内容是由无异常的$ \ text {u}（1）_ \ text {b-l} $量规对称的动机，并具有异国情调的非理性费用，我们需要执行额外的$ \ nathcal {z} _5 $对称性。暗物质候选者不与活性中微子混合，也没有任何衰减模式的SM颗粒。 DM与深色辐射以右手中微子的形式与深色辐射一起，通过由重B-L仪表玻色子介导的Sm fermions的平衡灭绝。为了避免Higgs的DM过量生产，并遵守Lyman-$α$界限，我们在低温加热的情况下使用$ 4 \; \ text {Mev} \ lyssim t_ \ lysssim t_ \ text {rh} \ text {rh} \ sextsim 5 \ \ \ \ \ \ \ \ text {gev} $。我们的设置预测对$Δn_\ text {fef。} $的贡献，该$降低了较大的DM质量，并且低于即将到来的精度测量值（例如CMB-S4）的灵敏度。对信号的未来观察$Δn_\ text {fef。} \ gtrsim 0.012 $将排除我们的场景。我们进一步勾勒出在这个统一的框架中也可以实现通货膨胀，再加热和Affleck-dine男生成。
We extend the Dirac Scotogenic model with the aim of realizing neutrino masses together with the mass of a keV-scale dark matter (DM) candidate via the same one-loop topology. Two of the Standard Model (SM) neutrinos become massive Dirac fermions while the third one remains massless. Our particle content is motivated by an anomaly free $\text{U}(1)_\text{B-L}$ gauge symmetry with exotic irrational charges and we need to enforce an additional $\mathcal{Z}_5$ symmetry. The dark matter candidate does not mix with the active neutrinos and does not have any decay modes to SM particles. DM is produced together with dark radiation in the form of right handed neutrinos via out of equilibrium annihilations of the SM fermions mediated by the heavy B-L gauge boson. In order to avoid DM over-production from Higgs decays and to comply with Lyman-$α$ bounds we work in a low temperature reheating scenario with $4\;\text{MeV}\lesssim T_\text{RH}\lesssim 5\;\text{GeV}$. Our setup predicts a contribution to $ΔN_\text{eff.}$ that decreases for larger DM masses and is below the sensitivity of upcoming precision measurements such as CMB-S4. A future observation of a signal with $ΔN_\text{eff.}\gtrsim 0.012$ would exclude our scenario. We further sketch how inflation, reheating and Affleck-Dine baryogenesis can also be potentially realized in this unified framework.
