论文标题
解开$ z $衰减中的深色玻色子的旋转
Untangling the spin of a dark boson in $Z$ decays
论文作者
论文摘要
我们将$ z $ -BOSON DECAY $ z \ toγ\，x $分析为光子（$γ$），以及属于黑暗或僻静部门的假设光玻色子（$ x $）。由于其与标准模型场的微弱相互作用，这种暗玻色子表现为检测器中缺少能量。我们考虑$ x $ spin-1（无质量的暗光子），spin-0（类似于轴的）和spin-2（类似重力的）颗粒的粒子，并探索解开其旋转起源的方式。所有这些方案都预测了这种衰变的通用签名，其特征是$ z $质量中心在$ z $的$ z $质量中的一半，以及与$ x $ boson相关的中微子样缺失的能量。我们表明，如果应以$ e^+e^ - $ colliders发现$ z \toγ\，x $信号，则在$ e^+e^ - \ to z \toγ\toγ\中，单色光子的角度分布可以提供一个清晰的探针，以区分$ j = 1 $ j = 1 $ j = 1 $ j = 1 $ $ j = 0/2 $ j = 0/2 $ $ j = $ j = 0/2 $ $ $ $
We analyze the $Z$-boson decay $Z\to γ\, X$ into a photon ($γ$) plus a hypothetical light boson ($X$) belonging to a dark or secluded sector. Due to its feeble interactions with Standard Model fields, this dark boson is behaving as missing energy in the detector. We consider for $X$ the cases of spin-1 (massless dark-photon), spin-0 (axion-like), and spin-2 (graviton-like) particles and explore the way to untangle its spin origin. All these scenarios predict a universal signature for this decay, characterized by a single mono-chromatic photon in the $Z$ center of mass, with energy about half of the $Z$ mass, plus a neutrino-like missing energy associated to the $X$ boson. We show that if the $Z\to γ\, X$ signal should be discovered at $e^+e^-$ colliders, the angular distribution of the mono-chromatic photon in $e^+e^-\to Z\to γ\, X$ can provide a clean probe to discriminate between the $J=1$ and alternative $J=0/2$ spin nature of the $X$ dark boson.
