Constraints on lepton number violating short-range interactions from $|ΔL|=2$ processes
Nestor Quintero
备注：
8 pages, 1 figure. v3: references added, discussion extended, section IV included, conclusions unchanged, matches with version published in Phys. Lett. B
In this work we study the short-range contributions that induce effective lepton number violating (LNV) interactions. We obtain a full set of constraints on the effective short-range couplings from a large variety of low-energy $|ΔL|= 2$ processes of pseudoscalar mesons $K, D, D_s, B$, and $τ$-lepton. These constraints provide complementary and additional information to the one obtained from the neutrinoless double-$β$ ($0νββ$) decay. As expected, the bounds on electron-electron short-range couplings are the only ones that are strongly constrained by the $0νββ$ decay. Although weaker, LNV effective couplings with different flavours are not accessible to $0νββ$ decay and these can be probe by the $|ΔL|= 2$ processes in consideration.
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。
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.
Probing unparticle theory via lepton flavor violating process $J/ψ\to ll'$ at BESIII
轻子味破坏过程$J/ψ\to ll' (l\neq l')$是探索非粒子理论的理想场所。在标准模型中，这一过程只能发生在环的层次上，因此应该受到很大的抑制，而在非粒子模型中，这一过程发生在树的层次上，其贡献对于实际测量可能是相当大的。此外，BESIII将提供最大的关于$J/ψ$的数据库，使更精确的测量成为可能。此外，对于这种纯轻子衰变，背景相对较低，信号会更清晰。我们的工作仔细研究了从理论和实验两个方面观察这些过程的可能性。
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