The Light Sgoldstino Phenomenology: Explanations for the Muon $(g-2)$ Deviation and KOTO Anomaly

Abstract

In this work, we study the long-standing experimental anomaly in muon $(g-2)$ and also recent anomalous excess in $K_L\to \pi^0+\nu\bar\nu$ at the J-PARC KOTO experiment with sgoldstino. After supersymmetry breaking, the interactions between quarks and sgoldstino ($s$) make the decays $K\to \pi+s$ sizable through loop diagrams, which affects the measurements of decays $K\to \pi+\mathrm{invisible}$. Furthermore, the couplings between photons and sgoldstino contribute to $\Delta a_\mu$ as well as the bino-slepton contribution. With satisfying all known experimental constraints such as from NA62, E949, E137, Orsay, KTEV and CHARM experiments, these two anomalies can be explained simultaneously. The mass of CP-even sgoldstino is close to the neutral pion mass which does not violate the Grossman-Nir bound. The parameter space can be further tested in future NA62, DUNE experiments, as well as experiments in the LHC.