Speaker
Description
In R-parity-violating (RPV) supersymmetry (SUSY), GeV-scale bino-like neutralinos are allowed by all constraints and can be produced in association with a baryon in $B$-meson decays via certain $\bar U \bar D \bar D$ operators. We investigate theoretical scenarios with a pair of non-vanishing RPV couplings at the low-energy scale. With one RPV coupling governing the neutralino production rate and another determining its lifetime, this scenario can lead to large signals with a displaced-vertex signatures in the tracking volume of $B$-factories. We study the discovery potential of the ongoing Belle~II experiment for such signatures with a new partial-reconstruction techniques that ensures high efficiency for reconstruction of relatively heavy long-lived particles and achieves much greater sensitivity than that of full reconstruction. Studying the signal processes as well as potential background sources, we perform detailed Monte-Carlo simulation to determine the detector efficiency as a function of the lifetime and mass of the lightest neutralino. We proceed to obtain numerical results of the sensitivity reach of Belle~II, showing that large parts of the parameter space can be probed, beyond current bounds.
