论文标题
在$ z $衰减的未来$ e^+e^ - $ collider
Testing axion couplings to leptons in $Z$ decays at future $e^+e^-$ colliders
论文作者
论文摘要
我们研究了在拟议的高能量$ e^+e^ - $ colliders，cepc和fcc-ee的情况下，探测$ z $ boson的光Leptonic衰变的可能性的可能性。两个项目都计划以$ z $ pole运行，收集$ 10^{12} -10^{13} $可见$ z $衰减。我们表明，在搜索Leptonic $ Z $衰减中的Leptons从Leptons中排放出来的ALP时，这种巨大的统计数据可以使ALP耦合以前所未有的实验级别的水平将ALP耦合限制在瘦素上。特别是，在蒙特卡洛模拟框架内，我们估计CEPC/FCC -EE可以敏感不可见的ALP耦合至$ $ f_A/c^a__ {μμμ{μμμ} \大约1 $ tev- $ f_a $在其中$ f_a $是alp decay decay常数 - 对应于$ ns $ n-对应于$ n-^rmbr^rmmbr^rmmbr^rmmbr+ \大约3 \ times 10^{ - 11} $。
We study the possibility of probing the existence of a light, invisible, axion-like particle (ALP) $a$ in leptonic decays of the $Z$ boson at the proposed high-energy $e^+e^-$ colliders, CEPC and FCC-ee. Both projects plan to run at the $Z$ pole, collecting $10^{12}-10^{13}$ visible $Z$ decays. We show that, searching for the emission of an invisible ALP from leptons in leptonic $Z$ decays, this enormous statistics could allow to constrain the ALP couplings to leptons at an unprecedented level for laboratory experiments. In particular, within a Monte Carlo simulation framework, we estimate that CEPC/FCC-ee can be sensitive to the coupling of an invisible ALP to muons up to $f_a/C^A_{μμ} \approx 1$ TeV - where $f_a$ is the ALP decay constant - corresponding to ${\rm BR}(Z \to μ^+μ^-\,a) \approx 3\times 10^{-11}$.
