arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.07515hep-phhep-ex
收藏

双圈辐射跷跷板、μ子$g-2$和$τ$ -具有DM约束的轻子味破坏

Two-loop radiative seesaw, muon $g-2$, and $τ$-lepton-flavor violation with DM constraints

Chuan-Hung Chen, Takaaki Nomura

摘要:

四次标量耦合$λ_5$项在Ma模型中违反轻子数两个单位,当该模型应用于轻子味违反(LFV)过程时,它是唯象地小的。为了通过量子环效应动态地产生$λ_5$参数并保留暗物质(DM)候选者,我们扩展了Ma模型,增加了一个$Z_2$ -奇矢量类轻子偶态和一个$Z_2$ -偶Majorana单态.在满足DM-核子散射截面上限的条件下,通过对希格斯玻色子和规范玻色子的新耦合,可以解释观测到的DM遗迹密度。除了中微子数据和LFV约束外,我们还发现DM遗迹密度可以显著地排除自由参数空间。尽管如此,由惰性带电希格斯粒子介导的μ子$g-2$可以拟合实验测量和SM结果之间的$4.2σ$偏差,并且当罕见的$μ\to (e γ, 3 e)$衰变被抑制时,$τ\to μγ$的分支比可以与电流上限一样大。此外,还发现所得到的$BR(τ\to μρ)$可以达到Belle II的灵敏度,积分光度为50 $ab^{-1}$。

英文摘要:

The quartic scalar coupling $λ_5$ term, which violates the lepton-number by two units in the Ma-model, is phenomenologically small when the model is applied to the lepton-flavor violation (LFV) processes. In order to dynamically generate the $λ_5$ parameter through quantum loop effects and retain the dark matter (DM) candidate, we extend the Ma-model by adding a $Z_2$-odd vector-like lepton doublet and a $Z_2$-even Majorana singlet. With the new couplings to the Higgs and gauge bosons, the observed DM relic density can be explained when the upper limits from the DM-nucleon scattering cross sections are satisfied. In addition to the neutrino data and LFV constraints, it is found that the DM relic density can significantly exclude the free parameter space. Nevertheless, the resulting muon $g-2$ mediated by the inert charged-Higgs can fit the $4.2σ$ deviation between the experimental measurement and the SM result, and the branching ratio for $τ\to μγ$ can be as large as the current upper limit when the rare $μ\to (e γ, 3 e)$ decays are suppressed. In addition, it is found that the resulting $BR(τ\to μρ)$ can reach the sensitivity of Belle II with an integrated luminosity of 50 $ab^{-1}$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑