We review how the muon anomalous magnetic moment (g − 2) and the quest for lepton flavor violation are intimately correlated. Indeed the decay µ → eγ is induced by the same amplitude for different choices of in-and outgoing leptons. In this work, we try to address some intriguing questions such as:Which hierarchy in the charged lepton sector one should have in order to reconcile possible signals coming simultaneously from g − 2 and lepton flavor violation? What can we learn if the g − 2 anomaly is confirmed by the upcoming flagship experiments at FERMILAB and J-PARC, and no signal is seen in the decay µ → eγ in the foreseeable future? On the other hand, if the µ → eγ decay is seen in the upcoming years, do we need to necessarily observe a signal also in g − 2?. In this attempt, we generally study the correlation between these observables in a detailed analysis of simplified models. We derive master integrals and fully analytical and exact expressions for both phenomena, and adress other flavor violating signals. We investigate under which conditions the observations can be made compatible and discuss their implications. Lastly, we discuss in this context several extensions of the SM, such as the Minimal Supersymmetric Standard Model, Left-Right symmetric model, B − L model, scotogenic model, two Higgs doublet model, Zee-Babu model, 331 model, and L µ − L τ , dark photon, seesaw models type I, II and III, and also address the interplay with 1

Abstract:A new H -ion source has been installed successfully and will be used to serve the China Spallation Neutron Source (CSNS). In this paper, we report various components of the ion source, including discharge chamber, temperature， cooling system, extraction electrodes, analyzing magnet, remote control system and so on. Compared to the previous experimental ion source, some improvements have been made to make the ion source more compact and convenient. In the present arrangement, the Penning field is generated by a pair of pole tip extensions on the 90°analyzing magnet instead of by a separate circuit. For the remote control system, F3RP61-2L is applied to the accelerator online control system for the first time. In the running of the ion source, a stable pulse H -beam with a current of 50 mA at an energy of 50 keV is produced. The extraction frequency and pulse width is 25 Hz and 500 s, respectively. Furthermore, an emittance scanner has been installed and measurements are in progress.

The Penning surface plasma source is adopted as the China Spallation Neutron Source (CSNS) H− ion source. The designed energy and beam current of the source are 50 keV and 20 mA, respectively, with a normalized root mean square (norm. rms.) emittance of 0.2 πmm·mrad. The construction of a H− ion source test stand has been completed, and the commissioning of the source is in progress. Stable H− ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H− beam is being prepared.