A hydrogen bubble chamber was exposed to a - beam of 3 GeV momentum. We observe

A hydrogen bubble chamber was exposed to a π^- beam of 3 GeV momentum. We observe an interaction with secondaries that are all neutral and two V⁰s pointing to the primary vertex. Measuring the two tracks of one of them, we find for the positive: p = 121 MeV, θ^- = -18.2° and ϕ^- = 15°, and for the negative: p⁺ = 1900 MeV, θ⁺ = 20.2° and ϕ⁺ = -15°. We know that θ and ϕ are the polar angles in a reference frame with polar axis z in the beam direction. What is the nature of the particle? Assume that the measurement errors give a ±4% resolution on the reconstructed mass of the V⁰.