标题： 揭示具有pNGB暗物质的惰性三重态沙漠区域及其引力波特征 显示英文标题

标题： Unveiling the inert Triplet desert region with a pNGB Dark Matter and its Gravitational Wave signatures

摘要： 在本工作中，我们将传统的无超电荷惰性三重态模型（ITM）的标量部分扩展，以包含第二个暗物质（DM）候选者，该候选者似乎是一种伪诺纳-戈德斯通玻色子（pNGB）。 具有扩展标量部分的常规ITM提供了一个DM候选者，并在不同实验中提供了新的特征，例如对撞机、引力波探测器等。 然而，迄今为止未见过的实验检测已对ITM参数空间施加了严格的限制。 此外，质量低于$1.9$TeV 的三重态，与现有或即将进行的对撞机灵敏度范围一致，已经由于强烈的$SU(2)_L$规范湮灭导致暗物质遗迹密度不足而被排除在DM观测之外。 通过一个复数$SU(2)_L$标量单态以及通过软破缺$U(1)$对称性来引入pNGB DM，有助于恢复三重态DM的亚TeV区域。 这种复苏依赖于两种DM粒子之间的高效转换。 利用这种相互转换，当三重态DM是两者中较轻的一个时，我们表明可以将三重态DM的贡献推至总遗迹密度的$50\% - 60\%$。 这比传统的只有一个DM候选者的ITM有了显著改进，后者最多只能达到$10\% - 20\%$。 此外，所涉及的双粒子DM框架还提供了沿各种组成场方向发生一阶相变的可能性。 其中，沿实数$SU(2)_L$单态方向的相变可能是一个强烈的相变，随后会在即将进行的空间引力波探测器如LISA、BBO、DECIGO等产生可探测的引力波信号，同时在各种DM和对撞机探索中产生独特且互补的特征。 显示英文摘要

摘要： In this work, we extend the scalar sector of the conventional hyperchargeless inert triplet model (ITM) to include a second dark matter (DM) candidate, which appears to be a pseudo-Nambu-Goldstone boson (pNGB). The usual ITM with an extended scalar sector offers a DM candidate along with novel signatures at different experiments, e.g., colliders, gravitational wave detectors, etc. Nevertheless, hitherto unseen experimental detections have placed stringent constraints on the ITM parameter space. Moreover, triplet masses lighter than $1.9$ TeV, consistent with the existing or upcoming collider sensitivity reach, are already excluded from the DM observable, as they yield an underabundant relic density due to a strong $SU(2)_L$ gauge annihilation. Inclusion of a pNGB DM, via a complex $SU(2)_L$ scalar singlet and through the soft-breaking of a $U(1)$ symmetry, helps to revive the sub-TeV regime of the triplet DM. This resurgence relies on a proficient conversion between the two DM species. Using this inter-conversion, with the triplet DM as the lighter one between the two, we show that it is possible to push the triplet DM contribution to $50\% - 60\%$ of the total relic density. This offers a significant improvement over the traditional ITM with a single DM candidate, where the same can at most reach $10\% - 20\%$. Besides, the concerned bipartite DM framework also offers the possibility of a first-order phase transition along various constituent field directions. Among these, the one along the real $SU(2)_L$ singlet direction can be a strong one which subsequently yields detectable gravitational wave signals at the upcoming space-based gravitational wave detectors such as LISA, BBO, DECIGO, etc., alongside distinctive and complementary signatures at the various DM and collider quests.