Dark Matter Signals from Cascade Annihilations

A leading interpretation of the electron/positron excesses seen by PAMELA and ATIC is dark matter annihilation in the galactic halo. Depending on the annihilation channel, the electron/positron signal could be accompanied by a galactic gamma ray or neutrino flux, and the non-detection of such fluxes constrains the couplings and halo properties of dark matter. In this paper, we study the interplay of electron data with gamma ray and neutrino constraints in the context of cascade annihilation models, where dark matter annihilates into light degrees of freedom which in turn decay into leptons in one or more steps. Electron and muon cascades give a reasonable fit to the PAMELA and ATIC data. Compared to direct annihilation, cascade annihilations can soften gamma ray constraints from final state radiation by an order of magnitude. However, if dark matter annihilates primarily into muons, the neutrino constraints are robust regardless of the number of cascade decay steps. We also examine the electron data and gamma ray/neutrino constraints on the recently proposed "axion portal" scenario.Comment: 36 pages, 11 figures, 7 tables; references adde

Secure Software Engineering Group

Abstract. Parameterized runtime monitoring formalisms allow predicates to bind free variables to values during the program’s execution. Some runtime monitoring tools, like J-LO, increase the formalism’s expressiveness by allowing predicates to query variables already during the matching process. This is problematic because, if no special care is taken, the predicate’s evaluation may need to query a variable that has not yet been bound, rendering the entire formula meaningless. In this paper we present a syntactic checking algorithm that recognizes meaningless formulas in future-time linear temporal logic. The algorithm assures that a predicate accesses a potentially unbound variable only when the truth value of this predicate cannot possibly impact the truth value of the entire formula at the time the predicate is being evaluated. Our approach allows users to specify a wide range of meaningful parameterized logic formulas, while at the same time forbidding such formulas that would otherwise have an unclear semantics due to insu cient bindings. We have implemented the checking algorithm in the J-LO runtime verification tool.