The CompositeParticle eta calculation uses the secondary vertex and PV positions to calculate pseudorapidity. This choice was not clear to users and doesn't give sensible results for non-displaced vertices. It could also provide worse resolution than a momentum based calculation for fully reconstructed particles.
This MR:
CompositeParticle::eta
CompositeParticle::eta_position and CompositeParticle::eta_momentum
eta with eta_position and eta_momentum in all selections. Unless the line authors' intentions were clear, I used eta_position for lines selecting partially reconstructed decays and eta_momentum for lines selecting fully reconstructed decays.FYI @gligorov