我们研究了新的希格斯玻色子，$pp\to W^+W^- \to \ellν_\ell \ell^\primeν_{\ell^\prime}$和中性轻子，$ν_{4}$，通过过程$pp \to H \to ν_4 ν_μ\to W μν_μ\to \ellν_\ell μν_μ$耦合$H-ν_{4}-ν_μ$和$W-ν_{4}-μ$模型中的贡献。与天真的期望相反，我们发现，$pp\to WW$的贡献可以是非常大的，同时满足标准$H\to WW$和$H\toγγ$搜索的约束。即使是ATLAS在$pp\to WW$中观察到的过量，如果按表面价值来考虑，也可以很容易地容纳。各种运动学分布很好地拟合实验确定的。这种情况可以出现在例如两个希格斯偶极子模型与矢量轻子。
英文摘要：
We study contributions to $pp\to W^+W^- \to \ellν_\ell \ell^\primeν_{\ell^\prime}$ in models with a new Higgs boson, $H$, and a neutral lepton, $ν_{4}$, with couplings $H-ν_{4}-ν_μ$ and $W-ν_{4}-μ$ through the process $pp \to H \to ν_4 ν_μ\to W μν_μ\to \ellν_\ell μν_μ$. Contrary to naive expectations, we find that contributions to $pp\to WW$ can be very large while satisfying constraints from standard $H\to WW$ and $H\toγγ$ searches. Even the excess observed by ATLAS in $pp\to WW$, if taken at face value, can be easily accommodated. The various kinematic distributions fit nicely the experimentally determined ones. This scenario can arise for example in a two Higgs doublet model with vectorlike leptons.
The discovery of a non-zero rate for a lepton flavor violating decay mode of the Higgs boson would definitely be an indication of New Physics. We review the prospects for such signal in Two Higgs Doublet Models, in particular for Higgs boson decays into $τμ$ final states. We will show that this scenario contains all the necessary ingredients to provide large flavor violating rates and still be compatible with the stringent limits from direct searches and low-energy flavor experiments.
Flavor violating top decays and flavor violating quark decays of the Higgs boson
在标准模型中，顶夸克和希格斯玻色子的味道违反衰变被高度抑制。此外，顶粒子和希格斯粒子的味道违反衰变在MSSM中也很小，在当前或不久的将来的实验中无法观察到。在这项工作中，我们表明，更大的分支比，这些衰变可以实现在一个扩展的MSSM模型与一个额外的矢量，如夸克生成。具体来说，我们表明，在扩展模型中，可以实现分支比$t\to h^0 c$和$t\to h^0 u$作为目前的实验上限由ATLAS和CMS合作。我们还分析了希格斯玻色子的味违反夸克衰变，即，$h^0\to b\bar s + \bar b s$和$h^0\to b\bar d + \bar b d$。这里我们再次发现，这些衰变的分支比可以和$O(1)\%$一样大。分析是在希格斯扇区的CP阶段列入，CP阶段的分支比的效果进行了研究。具体地说，希格斯扇形谱和混合计算涉及夸克和镜像夸克，方和镜像方的循环符合希格斯玻色子质量约束。由此产生的有效拉格朗日包含矢量夸克代诱导味道违反衰变在树的水平。对预测的分支比的测试可能来自LHC 13的进一步数据，并且这种分支比也可以在未来的对撞机中获得，例如希格斯工厂，在那里希格斯与费米子的耦合将以更高的精度确定。
Charged lepton flavor violation on target at GeV scale
我们研究了几GeV的轻子味破坏过程$e+ T \to τ+T'$。这一过程可以通过实验研究，引导GeV级的电子或正电子束在内部或固定的目标。我们研究了一些低能轻子味破坏相互作用对这个过程的影响。我们研究了这个过程对这些低能轻子味破坏相互作用的灵敏度，并将它们与轻子味破坏$τ$衰变过程的灵敏度进行了比较。与$τ$衰变过程相比，这一过程为研究$e-τ$转换的轻子味违反效应提供了另一种途径，可以在世界上许多实验室已有的GeV电子或正电子束装置上进行探索。
Recently, it was pointed out that the electron and muon g-2 discrepancies can be explained simultaneously by a flavor-violating axion-like particle (ALP). We show that the parameter regions favored by the muon g-2 are already excluded by the muonium-antimuonium oscillation bound. In contrast, those for the electron g-2 can be consistent with this bound when the ALP is heavier than 1.5 GeV. We propose to search for a signature of the same-sign and same-flavor lepton pairs and the forward-backward muon asymmetry to test the model at the Belle II experiment.
在标准模型的味道之谜背后，预计会有一些未知的动力学在起作用。有推测认为，这可能表现在兆量级的显著强度上。结果之一可能是轻子味破坏与轻子总数守恒。在中微子振荡实验中已经观察到这种现象，这种现象可能在TeV能量下表现得更突出，从而标志着一种全新的物理学。已经参考LHC研究了建议的味道破坏带电双轻子态。在这里，我们研究的味道违反带电四轻子的生产和检测在LHC被证明有一定的优势，在寻找轻子味道违反。分类的所有六个费米子运营商，在手征的基础上，并有助于这样的过程中，相应的截面为每个在14 TeV pp碰撞计算下的假设下，单一运营商的优势。我们进一步提出了新的物理尺度$Λ$的灵敏度达到的积分亮度。
We investigate CP-violating interactions involving the Higgs boson and gluons within an effective field theory approach, focusing on the specific class of new-physics scenarios where the Yukawa couplings of light quarks are zero or strongly suppressed compared to the standard-model expectations. We compute the contributions of the most relevant higher-dimensional operators of Weinberg type to the electric dipole moment of the neutron (nEDM), which are induced by Feynman diagrams that involve an effective CP-violating Higgs-gluon coupling and top-quark loops. The resulting nEDM sensitivities an…
We propose a new mechanism to explain neutrino masses with lepton number conservation, in which the Dirac neutrino masses are generated at the two-loop level involving a dark matter candidate. In this model, branching ratios of lepton flavor violating decays of the Higgs boson can be much larger than those of lepton flavor violating decays of charged leptons. If lepton flavor violating decays of the Higgs boson are observed at future collider experiments without detecting lepton flavor violating decays of charged leptons, most of the models previously proposed for tiny neutrino masses are excl…
We study constraints on light and feebly interacting bosons with lepton flavor violation from electron beam dump experiments. Scalar, vector, and dipole interactions of the bosons are analyzed, respectively, and excluded regions from the searches for decays into electron-positron pairs are derived. It is found that parameter regions unconstrained by flavor violating decays of muon can be excluded using the results of the E137 experiment. We also discuss the impact of the search for flavor violating decays of the light bosons in electron beam dump experiments.
Exotic Higgs decays are promising channels to discover new physics in the near future. We present a simple model with a new light scalar that couples to the Standard Model through a charged lepton-flavor violating interaction. This can yield exciting new signatures, such as $h \to e^+ e^+ μ^-μ^-$, that currently have no dedicated searches at the Large Hadron Collider. We discuss this model in detail, assess sensitivity from flavor constraints, explore current constraints from existing multi-lepton searches, and construct a new search strategy to optimally target these exotic, lepton-flavor vio…
