Multi-track event reconstruction to constrain the [formula omitted] background in Mu2e

Abstract

Mu2e experiment will search for the neutrinoless, coherent conversion of μ−→e− in the field of an Al nucleus. One of the expected backgrounds is p̄’s annihilating in the stopping target to produce signal-like e−’s. Although not a dominant background, it has a large uncertainty and cannot be suppressed by the timing cuts used to reduce the prompt background. However, at Mu2e energies, pp̄ annihilation is the only source of events with multiple, simultaneous particles coming from the stopping target. We utilized this unique feature and developed a novel way to reconstruct multi-track events and estimate the p̄ background.