论文标题
从$ z $和$τ$衰减重新访问中微子的自我交流约束
Revisiting Neutrino Self-Interaction Constraints from $Z$ and $τ$ decays
论文作者
论文摘要
鉴于中微子的难以捉摸，他们的自我交流特别困难。然而，可以使用陆地实验的数据来设置这种相互作用强度的上限。在这项工作中，我们着重于对$ z $ boson的无形衰减宽度以及在存在中微子耦合到相对较轻的标量的情况下，$ z $ boson的无形衰减宽度以及Leptonic $τ$衰减的宽度。对于无形的$ z $衰减，我们通过考虑三体bremsstrahlung以及对两体衰减的循环校正来得出一套完整的约束。尽管通常认为后者给出相当较弱的限制，但我们发现，通过干扰标准模型图，它实际上产生了竞争性的约束。就$τ$的松性衰减而言，我们对中微子自我相互作用的第一个限制在整个轻标量介质的整个质量范围内都是有效的。我们对中微子自我交流的界限是$ m_ϕ \ gtrsim 300 $ mev和更喜欢$ν_τ$的交互的领导。鉴于最近提出的减轻这种耦合的缓解，这种$ν$ - 湿的标量的界限尤其重要。
Given the elusive nature of neutrinos, their self-interaction is particularly difficult to probe. Nevertheless, upper limits on the strength of such an interaction can be set by using data from terrestrial experiments. In this work we focus on additional contributions to the invisible decay width of $Z$ boson as well as the leptonic $τ$ decay width in the presence of a neutrino coupling to a relatively light scalar. For invisible $Z$ decays we derive a complete set of constraints by considering both three-body bremsstrahlung as well as the loop correction to two-body decays. While the latter is usually regarded to give rather weak limits we find that through the interference with the Standard Model diagram it actually yields a competitive constraint. As far as leptonic decays of $τ$ are concerned, we derive a first limit on neutrino self-interactions that is valid across the whole mass range of a light scalar mediator. Our bounds on the neutrino self-interaction are leading for $m_ϕ\gtrsim 300$ MeV and interactions that prefer $ν_τ$. Bounds on such $ν$-philic scalar are particularly relevant in light of the recently proposed alleviation of the Hubble tension in the presence of such couplings.
