From the post "Particle Wave Duality, Seriously MP",
ψ=mc212π1x3
∫b→∞aψ∂x=mc224π1a2=+finite --- (*)
where a is the radius of the particle. The wave ψ was found to be of finite extend. This is the boundary between wave and particle; beyond xb where ψ is small as delimited by (*), the particle cease to have wave property.
ψb=mc212π1x3b
where ψb→0
Theoretically.