标题： 无中微子双β衰变：马约拉纳态之间的干涉 显示英文标题

标题： Neutrinoless double-beta decay at colliders: interference between Majorana states

摘要： 重性中性轻子（HNLs）是假设粒子，能够解释基本物理中的多个谜题，首先是中微子振荡。 作为标准模型相互作用的“纯种”，这些粒子可以具有马约拉纳质量，从而导致总轻子数的破坏。 因此，轻子数破坏（LNV）过程成为HNLs的关键特征，许多实验都在研究这一现象。 在本工作中，我们证明如果HNLs是中微子质量的唯一来源，马约拉纳态之间的破坏性干涉会抑制同号双轻子信号。 在大HNL耦合的物理上有趣的案例中，这种抑制类似于HNL对中微子质量贡献的抵消。 然而，该信号可以比仅来自温伯格算符的信号大得多。 我们确定了此类现实HNL模型参数空间中，LNV信号在大型强子对撞机（LHC）和未来FCC-hh中达到最大的区域。 我们的结果是在有效W近似下获得的，该近似允许解析处理，并对模型参数有清晰的依赖关系。 尽管是近似的，但它们被认为在几倍的范围内是正确的。 显示英文摘要

摘要： Heavy neutral leptons (HNLs) are hypothetical particles able to explain several puzzles of fundamental physics, first and foremost - neutrino oscillations. Being sterile with respect to Standard Model interactions, these particles admit Majorana masses, allowing for violation of the total lepton number. Lepton number violating (LNV) processes thus become a key signature of HNLs, pursued by many experiments. In this work, we demonstrate that if HNLs are the sole origin of neutrino masses, destructive interference between Majorana states suppresses the same-sign di-lepton signal. In the phenomenologically interesting case of large HNL couplings, such suppression is akin to the cancellation of HNLs' contributions to neutrino masses. Nevertheless, the signal can be much larger than coming from the Weinberg operator alone. We identify regions of the parameter space of such realistic HNL models where the LNV signal is maximised at the LHC and future FCC-hh. Our results are obtained within the effective W approximation which allows for analytic treatment and gives a clear dependence on the model parameters. Although approximate, they are argued to be correct within a factor of a few.