Long-lived light neutralinos at Belle II

• Published in: The journal of high energy physics Vol. 2021; no. 2
• Main Authors: Dey, Sourav, Dib, Claudio O., Helo, Juan Carlos, Nayak, Minakshi, Neill, Nicolás A., Soffer, Abner, Wang, Zeren Simon
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2021; Springer Nature B.V
• Subjects: Apexes; Classical and Quantum Gravitation; Elementary Particles; Experiments; Fermions; High energy physics; Leptons; Light; Monte Carlo simulation; Phenomenology; Physics; Physics and Astronomy; Pions; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Supersymmetry; Symmetry; Supersymmetry Phenomenology
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP02(2021)211

A bstract We consider light neutralinos of mass about 1 GeV, produced from τ lepton rare decays at Belle II, in the context of R-parity-violating (RPV) supersymmetry. With large and clean samples of τ leptons produced at the Belle II experiment, excellent sensitivity to such light neutralinos with the exotic signatures of displaced vertices is expected. We focus on two benchmark scenarios of single RPV operators, λ 311 ′ L 3 Q 1 D ¯ 1 and λ 312 ′ L 3 Q 1 D ¯ 2 , which induce both the production and decay of the lightest neutralino. For the reconstruction of a displaced vertex, we require at least two charged pions in the final states. We perform Monte-Carlo simulations for both signal and background events, and find that Belle II can explore regions in the parameter space competitive with other probes. In particular, for the λ 311 ′ scenario, it can put limits up to two orders of magnitude stronger than the current bounds.