Radiative Neutralino Decay in Split Supersymmetry

Abstract

Radiative neutralino decay ${\chi }_2^0->{\chi }_1^0\gamma$ is studied in a Split Supersymmetric scenario, and compared with mSUGRA and MSSM. This 1-loop process has a transition amplitude which is often quite small, but has the advantage of providing a very clear and distinct signature: electromagnetic radiation plus missing energy. In Split Supersymmetry this radiative decay is in direct competition with the tree-level three-body decay ${\chi }_2^0->{\chi }_1^{0}f\overline{f}$, and we obtain large values for the branching ratio $B({\chi }_2^0->{\chi }_1^0\gamma )$ which can be close to unity in the region $M_2\sim M_1$. Furthermore, the value for the radiative neutralino decay branching ratio has a strong dependence on the split supersymmetric scale $\tilde{m}$, which is otherwise very difficult to infer from experimental observables.

Comments: 15 pages and 10 figures