# Reaction in Particle Physics

I'm currently checking some reactions if they are allowed. One of them is $$\nu_\mu p\to\mu^-\Delta^{++}$$

Since this is a weak interaction I've checked the Baryon and Lepton number, Spin and the charge. It seems that the reaction is allowed. Is that really possible?

Some of my colleagues argued that the lepton number is not conserved. But I can not agree with them. Did I make a mistake?

LHS: Lepton number: +1 RHS: Lepton number: +1